A large area efficient trigger scintillator with SiPM read out
D. Grzonka; P. Bergmann; T. Hahnraths von der Gracht; P. Kulessa; W. Parol; T. Sefzick; J. Ritman; M. Zielinski
abstract
A large area plastic scintillator detector system with SiPM read out has been prepared in order to improve the trigger selectivity for reaction studies induced by an intense proton beam with a beam momentum of several GeV/c. The system consists of six trapezoidal modules, each with three plastic scintillator elements that are each equipped with 12 SiPMs. The detection of a charged particle is based on registering coincident signals in several SiPMs. By requiring a signal on at least two of the SiPMs, the noise rate is negligible and a detection efficiency close to 100% is achieved.
Search for the eta mesic 3He in the pd->dppi0 reaction with the WASA-at-COSY facility
P. Adlarson, ..., E. Czerwiński, A. Khreptak, W. Krzemień, P. Moskal, O. Rundel, I. Schätti-Ozerianska, M. Skurzok, M.J. Zieliński, et al.
abstract
The excitation function for the pd -> dppi0 reaction has been measured by WASA-at-COSY experiment with the aim of searching for 3He-eta mesic nuclei. The measurement in the vicinity of eta meson production was performed using a ramped proton beam. The data analysis and interpretation was carried out with the assumption that the eta-mesic Helium decays via the formation of an intermediate N*(1535) resonance. No direct signal of the eta-mesic nucleus is observed in the excitation function. We determine a new improved upper limit for the total cross section for the bound state production and decay in the pd -> (3He-eta)bound -> dppi0 process. It varies between 13 nb to 24 nb for the bound state with width in the range Gamma (5,50) MeV.
Differential Cross Sections for Neutron-Proton Scattering in the Region of the d*(2380) Dibaryon Resonance
P. Adlarson, ..., E. Czerwiński, A. Khreptak, W. Krzemień, P. Moskal, O. Rundel, I. Schätti-Ozerianska, M. Skurzok, M.J. Zieliński, et al.
abstract
Differential cross-sections have been extracted from exclusive and kinematically complete high-statistics measurements of quasifree polarized np scattering performed in the energy region of the d*(2380) dibaryon resonance covering the range of beam energies Tn=0.98?1.29 GeV (s=2.32?2.44 GeV). The experiment was carried out with the WASA-at-COSY setup having a polarized deuteron beam impinged on the hydrogen pellet target and utilizing the quasifree process dp->np + p_spectator. In this way, the np differential cross-section sigma(theta) was measured over a large angular range. The obtained angular distributions complement the corresponding analyzing power Ay(theta) measurements published previously. A SAID partial-wave analysis incorporating the new data strengthens the finding of a resonance pole in the coupled D33-G33 waves
Three-nucleon dynamics in dp breakup collisions using the WASA detector at COSY-Jülich
P. Adlarson, ..., E. Czerwiński, A. Khreptak, W. Krzemień, P. Moskal, M. Skurzok, M.J. Zieliński, et al.
abstract
The differential cross section for the 1 H (d, pp)n breakup reaction at deuteron beam energy of 340 MeV
has been measured with the use of the WASA detector at COSY-Jülich. The set of proton-proton coincidences
registered at the Forward Detector has been analyzed on a dense grid of kinematic variables, giving in total
around 5600 data points. The cross-section data are compared to theoretical predictions based on the state-of-
the-art nucleon-nucleon potentials, combined with a three-nucleon force or the Coulomb interaction or carried
out in a relativistic regime.
Search for eta mesic 3He with the WASA-at-COSY facility in the pd-> 3He 2gamma and pd-> 3He 6gamma reactions
P. Adlarson, ..., E. Czerwiński, O. Khreptak, W. Krzemień, P. Moskal, O. Rundel, I. Schätti-Ozerianska, M. Skurzok, M.J. Zieliński, et al.
abstract
We report on the experimental search for the bound state of an eta meson and 3He nucleus performed using the WASA-at-COSY detector setup. In order to search for the eta-mesic nucleus decay, the pd->3He2gamma and pd->3He6gamma channels have been analysed. These reactions manifest the direct decay of eta meson bound in 3He nucleus. This non-mesonic decay channel has been considered for the first time. When taking into account only statistical errors, the obtained excitation functions reveal a slight indication for a possible bound state signal corresponding to an 3He-eta nucleus width Gamma above 20 MeV and binding energy Bs between 0 and 15 MeV. However, the determined cross sections are consistent with zero in the range of the systematic uncertainty. Therefore, as final result we estimate only the upper limit for the cross section of the eta-mesic 3He nucleus formation followed by the eta meson decay which varies between 2 nb and 15 nb depending on possible bound state parameters.
Simulation studies of annihilation-photon's polarisation via Compton scattering with the J-PET tomograph
N. Krawczyk, B.C. Hiesmayr, J. Chhokar, C. Curceanu, E. Czerwiński, K. Dulski, A. Gajos, M. Gorgol, N. Gupta-Sharma, B. Jasińska, D. Kisielewska, G. Korcyl, P. Kowalski, W. Krzemień, T. Kozik, E. Kubicz, M. Mohammed, Sz. Niedźwiecki, M. Pałka, M. Pawlik-Niedźwiecka, L. Raczyński, J. Raj, K. Rakoczy, Z. Rudy, S. Sharma, Shivani, R.Y. Shopa, M. Silarski, M. Skurzok, W. Wiślicki, B. Zgardzińska, M. Zieliński, P. Moskal
abstract
J-PET is the first positron-emission tomograph (PET) constructed from plastic scintillators. It was optimized for the detection of photons from electron-positron annihilation. Such photons, having an energy of 511 keV, interact with electrons in plastic scintillators predominantly via the Compton effect. Compton scattering is at most probable at an angle orthogonal to the electric field vector of the interacting photon. Thus registration of multiple photon scatterings with J-PET enables to determine the polarization of the annihilation photons. In this contribution we present estimates on the physical limitation in the accuracy of the polarization determination of 511 keV photons with the J-PET detector.
Search for polarized antiproton production
D. Grzonka, D. Alfs, A. Asaturyan, M. Carmignotto, M. Diermaier, W. Eyrich, B. Głowacz, F. Hauenstein, T. Horn, K. Kilian, D. Lersch, S. Malbrunot-Ettenauer, A. Mkrtchyan, H. Mkrtchyan, P. Moskal, P. Nadel-Turonski, W. Oelert, J. Ritman, T. Sefzick, V. Tadevosyan, E. Widmann, M. Wolke, S. Zhamkochyan, M. Zieliński, A. Zink, J. Zmeskal
abstract
The production of antiprotons is studied in view of possible polarization effects as basis for a polarized antiproton beam. If antiprotons are produced with some polarization, a quite simple procedure for the generation of a polarized antiproton beam could be worked out. The experiments are performed at the CERN PS test beam T11 where secondary particles with momenta around 3.5 GeV/c are selected. The polarization analysis is performed by measuring the asymmetry of the elastic pp-scattering in the Coulomb-nuclear interference region. The detection system includes Cherenkov and tracking detectors for the particle identification and the 3d track reconstruction. Details on the detection system and the status of the analysis are given.
Examination of the Production of an Isotensor Dibaryon in the pp->pppi+pi- Reaction
P. Adlarson, ..., E. Czerwiński, O. Khreptak, W. Krzemień, P. Moskal, O. Rundel, I. Schätti-Ozerianska, M. Skurzok, M.J. Zieliński, et al.
abstract
Exclusive measurements of the quasi-free pp->pppi+pi- reaction have been performed by means of pd collisions at Tp = 1.2 GeV using the WASA detector setup at COSY. Total and differential cross sections have been obtained covering the energy region Tp=1.08-1.36 GeV (sqrt(s) = 2.35 - 2.46 GeV), which includes the regions of N*(1440) and Delta(1232)Delta(1232) resonance excitations. Calculations describing these excitations by t-channel meson exchange are at variance with experimental differential cross sections and underpredict substantially the measured total cross section. An isotensor DeltaN dibaryon resonance with I(JP)=2(1+) produced associatedly with a pion is able to overcome these deficiencies. Such a dibaryon was predicted by Dyson and Xuong and more recently calculated by Gal and Garcilazo.
Evaluation of Single-Chip, Real-Time Tomographic Data Processing on FPGA - SoC Devices
G. Korcyl, P. Białas, C. Curceanu, E. Czerwiński, K. Dulski, B. Flak, A. Gajos, B. Głowacz, M. Gorgol, B. C. Hiesmayr, B. Jasińska, K. Kacprzak, M. Kajetanowicz, D. Kisielewska, P. Kowalski, T. Kozik, N. Krawczyk, W. Krzemień, E. Kubicz, M. Mohammed, Sz. Niedźwiecki, M. Pawlik- Niedźwiecka, M. Pałka, L. Raczyński, P. Rajda, Z. Rudy, P. Salabura, N. G. Sharma, S. Sharma, R. Y. Shopa, M. Skurzok, M. Silarski, P. Strzempek, A. Wieczorek, W. Wiślicki, R. Zaleski, B. Zgardzińska, M. Zieliński, P. Moskal
abstract
A novel approach to tomographic data processing
has been developed and evaluated using the Jagiellonian PET (J-
PET) scanner as an example. We propose a system in which there
is no need for powerful, local to the scanner processing facility,
capable to reconstruct images on the fly. Instead we introduce a
Field Programmable Gate Array (FPGA) System-on-Chip (SoC)
platform connected directly to data streams coming from the
scanner, which can perform event building, filtering, coincidence
search and Region-Of-Response (ROR) reconstruction by the
programmable logic and visualization by the integrated
processors. The platform significantly reduces data volume
converting raw data to a list-mode representation, while
generating visualization on the fly.
Lyman-alpha source for laser cooling antihydrogen
G. Gabrielse, B. Glowacz, D. Grzonka, C. D. Hamley, E. A. Hessels, N. Jones, G. Khatri, S. A. Lee, C. Meisenhelder, T. Morrison, E. Nottet, C. Rasor, S. Ronald, T. Skinner, C. H. Storry, E. Tardiff, D. Yost, D. Martinez Zambrano, M. Zieliński
abstract
We present a Lyman-alpha laser developed for cooling trapped antihydrogen. The system is based on a pulsed Ti:sapphire laser operating at 729 nm that is frequency doubled using an LBO crystal and then frequency tripled in a Kr/Ar gas cell. After frequency conversion, this system produces up to 5.7 mW of average power at the Lyman-alpha wavelength. This laser is part of the ATRAP experiment at the antiproton decelerator in CERN.
Backward single-pion production in the pd->3Hepi0 reaction with WASA-at-COSY
P. Adlarson, ..., E. Czerwiński, O. Khreptak, W. Krzemień, P. Moskal, O. Rundel, I. Schätti-Ozerianska, M. Skurzok, M.J. Zieliński, et al.
abstract
New data on the production of single neutral pions in the pd->3Hepi0 reaction are presented. For fifteen proton beam momenta between pp=1.60GeV/c and pp=1.74GeV/c, differential cross sections are determined over a large fraction of the backward hemisphere. Since the only previous systematic measurements of single-pion production at these energies were made in collinear kinematics, the present work constitutes a significant extension of the current knowledge on this reaction. Even this far above the production threshold, significant changes are found in the behaviour of the angular distributions over small intervals in beam momentum.
Feasibility study of the time reversal symmetry tests in decay of metastable positronium atoms with the J-PET detector
A. Gajos, C. Curceanu, E. Czerwinski, K. Dulski, M. Gorgol, N. Gupta-Sharma, B.C. Hiesmayr, B. Jasinska, K. Kacprzak, L. Kaplon, D. Kisielewska, G. Korcyl, P. Kowalski, T. Kozik, W. Krzemien, E. Kubicz, M. Mohammed, Sz Niedzwiecki, M. Paalka, M. Pawlik-Niedzwiecka, L. Raczynski, J. Raj, Z. Rudy, S. Sharma, Shivani, R. Shopa, M. Silarski, M. Skurzok, W. Wislicki, B. Zgardzinska, M. Zielinski, P. Moskal
abstract
This article reports on the feasibility of testing of the symmetry under reversal in time in a purely leptonic system constituted by positronium atoms using the J-PET detector. The present state of T symmetry tests is discussed with an emphasis on the scarcely explored sector of leptonic systems. Two possible strategies of searching for manifestations of T violation in non-vanishing angular correlations of final state observables in the decays of metastable triplet states of positronium available with J-PET are proposed and discussed. Results of a pilot measurement with J-PET and assessment of its performance in reconstruction of three-photon decays are shown along with an analysis of its impact on the sensitivity of the detector for the determination of T -violation sensitive observables.
Estimating the NEMA characteristics of the J-PET tomograph using the GATE package
P. Kowalski, W. Wiślicki, R.Y. Shopa, L. Raczyński, K. Klimaszewski, C. Curcenau, E. Czerwiński, K. Dulski, A. Gajos, M. Gorgol, N. Gupta-Sharma, B. Hiesmayr, B. Jasińska, Ł. Kapłon, D. Kisielewska-Kamińska, G. Korcyl, T. Kozik, W. Krzemień, E. Kubicz, M. Mohammed, S. Niedźwiecki, M. Pałka, M. Pawlik-Niedźwiecka, J. Raj, K. Rakoczy, Z. Rudy, S. Sharma, S. Shivani, M. Silarski, M. Skurzok, B. Zgardzińska, M. Zieliński, P. Moskal
abstract
A novel whole-body positron emission tomography (PET) system based on plastic scintillators is
developed by the J-PET Collaboration. It consists of plastic scintillator strips arranged axially in the
form of a cylinder, allowing the cost-effective construction of the total-body PET system. In order to
determine the properties of the scanner prototype and optimize its geometry, advanced computer
simulations were performed using the GATE (Geant4 application for tomographic emission)
software.
The spatial resolution, sensitivity, scatter fraction and noise equivalent count rate were estimated
according to the National Electrical Manufacturers Association norm, as a function of the length
of the tomograph, the number of detection layers, the diameter of the tomographic chamber and
for various types of applied readout. For the single-layer geometry with a diameter of 85 cm, a strip
length of 100 cm, a cross-section of 4 mm × 20 mm and silicon photomultipliers with an additional
layer of wavelength shifter as the readout, the spatial resolution (full width at half maximum) in
the centre of the scanner is equal to 3 mm (radial, tangential) and 6 mm (axial). For the analogous
double-layer geometry with the same readout, diameter and scintillator length, with a strip crosssection
of 7 mm × 20 mm, a noise equivalent count rate peak of 300 kcps was reached at 40 kBq cc?1
activity concentration, the scatter fraction is estimated to be about 35% and the sensitivity at the
centre amounts to 14.9 cps kBq?1. Sensitivity profiles were also determined.
Isotensor Dibaryon in the pp->pppi+pi- Reaction?
P. Adlarson, ..., E. Czerwiński, O. Khreptak, W. Krzemień, P. Moskal, O. Rundel, I. Schätti-Ozerianska, M. Skurzok, M.J. Zieliński, et al.
abstract
Exclusive measurements of the quasi-free pp->pppi+pi- reaction have been carried out at WASA@COSY by means of pd collisions at Tp = 1.2 GeV. Total and differential cross sections have been extracted covering the energy region Tp=1.08-1.36 GeV, which is the region of N*(1440) and Delta(1232)Delta(1232) resonance excitations. Calculations describing these excitations by t-channel meson exchange are at variance with the measured differential cross sections and underpredict substantially the experimental total cross section. An isotensor DeltaN dibaryon resonance with I(JP)=2(1+) produced associatedly with a pion is able to overcome these deficiencies.
Total and differential cross sections of eta-production in proton-deuteron fusion for excess energies between Q_eta=13MeV and Q_eta=81MeV
P. Adlarson, ...,E. Czerwiński, A. Khreptak, W. Krzemień, P. Moskal, O. Rundel, M. Skurzok, I. Schätti-Ozerianska, M. Zieliński, et al. (WASA-at-COSY Collaboration)
abstract
New data on both total and differential cross sections of the production of eta mesons in proton-deuteron fusion to 3He-eta in the excess energy region 13.6MeV < Q < 80.9 MeV are presented. These data have been obtained with the WASA-at-COSY detector setup located at the Forschungszentrum Julich, using a proton beam at 15 different beam momenta between p_p=1.60GeV/c and p_p=1.74GeV/c. While significant structure of the total cross section is observed in the energy region 20 MeV < Q < 60MeV, a previously reported sharp variation around Q ~ 50MeV cannot be confirmed. Angular distributions show the typical forward-peaking that was reported elsewhere. For the first time, it is possible to study the development of these angular distributions with rising excess energy over a large interval.
Importance of d-wave contributions in the charge symmetry breaking reaction dd->4Hepi0
P. Adlarson, ...,E. Czerwiński, O. Khreptak, W. Krzemień, P. Moskal, O. Rundel, M. Skurzok, M. Zieliński et al. (WASA-at-COSY Collaboration)
abstract
This letter reports the first measurement of the contribution of higher partial waves in the charge symmetry breaking reaction dd->4Hepi0 using the WASA-at-COSY detector setup at an excess energy of Q=60 MeV. The determined differential cross section can be parametrized as dsigma/domega=a+bcos2theta?, where theta? is the production angle of the pion in the center-of-mass coordinate system, and the results for the parameters are a=(1.55+-0.46(stat)+0.32-0.8(syst))pb/sr and b=(13.1+-2.1(stat)+1.0-2.7(syst))pb/sr. The data are compatible with vanishing p-waves and a sizable d-wave contribution. This finding should strongly constrain the contribution of the Delta isobar to the dd->4Hepi0 reaction and is therefore crucial for a quantitative understanding of quark mass effects in nuclear production reactions.
Spin dependence of eta meson production in proton-proton collisions close to threshold
P. Adlarson, ...,E. Czerwiński, O. Khreptak, W. Krzemień, P. Moskal, O. Rundel, M. Skurzok, M. Zieliński et al. (WASA-at-COSY Collaboration)
abstract
Taking advantage of the high acceptance and axial symmetry of the WASA-at-COSY detector, and
the high degree of the polarized proton beam of COSY, the reaction ~pp->pp eta has been measured
close to threshold to explore the analyzing power Ay. The angular distribution of Ay is determined
with the precision improved by more than one order of magnitude with respect to previous results
allowing a first accurate comparison with theoretical predictions. The determined analyzing power
is consistent with zero for an excess energy of Q=15 MeV signaling s wave production with no
evidence for higher partial waves. At Q=72 MeV the data reveals strong interference of Ps and
Pp partial waves and cancellation of (Pp) and Ss?Sd contributions. These results rule out the
presently available theoretical predictions for the production mechanism of the eta meson.
A Method to Produce Linearly Polarized Positrons and Positronium Atoms with the J-PET Detector
M. Mohammed, P. Białas, C. Curceanu, E. Czerwiński, K. Dulski, A. Gajos, B. Głowacz, M. Gorgol, B.C. Hiesmayr, B. Jasińska, D. Kisielewska, G. Korcyl, P. Kowalski, T. Kozik, N. Krawczyk, W. Krzemień, E. Kubicz, M. Pawlik-Niedźwiecka, S. Niedźwiecki, M. Pałka, L. Raczyński, J. Raj, Z. Rudy, N.G. Sharma, S. Sharma, Shivani, M. Skurzok, M. Silarski, A. Wieczorek, W. Wiślicki, B. Zgardzińska, M. Zieliński, P. Moskal
abstract
A method for creating linearly polarized positrons and ortho-positronium (o-Ps) atoms with the J-PET detector is presented. The unique geometry and properties of the J-PET tomography enable one to design a positron source such that the quantization axis for the estimation of the linear polarization of produced o-Ps can be determined on the event by event basis in a direction of the positron motion. We intend to use 22Na or other beta+ decay isotopes as a source of polarized positrons. Due to the parity violation in the beta decay, the emitted positrons are longitudinally polarized. The choice of the quantization axis is based on the known position of the positron emitter and the reconstructed position of the positronium annihilation. We show that the J-PET tomography is equipped with all needed components.
Human Tissue Investigations Using PALS Technique - Free Radicals Influence
B. Jasińska, B. Zgardzińska, G. Chołubek, M. Pietrow, M. Gorgol, K. Wiktor, K. Wysogląd, P. Białas, C. Curceanu, E. Czerwiński, K. Dulski, A. Gajos, B. Głowacz, B.C. Hiesmayr, B. Jodłowska-Jędrych, D. Kamińska, G. Korcyl, P. Kowalski, T. Kozik, N. Krawczyk, W. Krzemień, E. Kubicz, M. Mohammed, M. Pawlik-Niedźwiecka, S. Niedźwiecki, M. Pałka, L. Raczyński, Z. Rudy, N.G. Sharma, S. Sharma, R. Shopa, M. Silarski, M. Skurzok, A. Wieczorek, H. Wiktor, W. Wiślicki, M. Zieliński, P. Moskal
abstract
The positron annihilation lifetime spectroscopy was applied to the samples of the human uterine leiomyomas and the normal myometrium tissues taken from the selected place of the uterus during a surgery. The method indicated differences in values of the measured positron annihilation lifetime spectroscopy parameters (lifetimes and intensities) between healthy and diseased tissue samples. The additional measurements were performed either in darkness or in presence of visible light which influenced the free radicals present in both kind of tissues and, as a result, made changes in free annihilation and o-Ps decay lifetime and intensity values.
Preliminary Studies of J-PET Detector Spatial Resolution
M. Pawlik-Niedźwiecka, S. Niedźwiecki, D. Alfs, P. Białas, C. Curceanu, E. Czerwiński, K. Dulski, A. Gajos, B. Głowacz, M. Gorgol, B. C. Hiesmayr, B. Jasińska, D. Kisielewska, G. Korcyl, P. Kowalski, T. Kozik, N. Krawczyk, W. Krzemień, E. Kubicz, M. Mohammed, M. Pałka, L. Raczyński, J. Raj, Z. Rudy, Shivani, M. Silarski, M. Skurzok, N.G. Sharma, S. Sharma, R.Y. Shopa, A. Strzelecki, A. Wieczorek, W. Wiślicki, B. Zgardzińska, M. Zieliński, P. Moskal
abstract
The J-PET detector, based on long plastic scintillator strips, was recently constructed at the Jagiellonian University. It consists of 192 modules axially arranged into three layers, read out from both sides by digital constant-threshold front-end electronics. This work presents preliminary results of measurements of the spatial resolution of the J-PET tomograph performed with 22Na source placed at selected position inside the detector chamber.
Analysis procedure of the positronium lifetime spectra for the J-PET detector
K. Dulski , B. Zgardzińska , P. Białas , C. Curceanu E. Czerwiński , A. Gajos , B. Głowacz , M. Gorgol , B. C. Hiesmayr , B. Jasińska , D. Kisielewska-Kamińska , G. Korcyl , P. Kowalski , T. Kozik , N. Krawczyk , W. Krzemień , E. Kubicz , M. Mohammed , M. Pawlik-Niedźwiecka, S. Niedźwiecki , M. Pałka , L. Raczyński , J. Raj , Z. Rudy , N. G. Sharma, S. Sharma, Shivani, R. Y. Shopa, M. Silarski , M. Skurzok , A. Wieczorek , W. Wiślicki , M. Zieliński , P. Moskal
abstract
Positron Annihilation Lifetime Spectroscopy (PALS) has shown to be a powerful tool to study the nanostructures of porous materials. Positron Emissions Tomography (PET) are devices allowing imaging of metabolic processes e.g. in human bodies. A newly developed device, the J-PET (Jagiellonian PET), will allow PALS in addition to imaging, thus combining both analyses providing new methods for physics and medicine. In this contribution we present a computer program that is compatible with the J-PET software. We compare its performance with the standard program LT 9.0 by using PALS data from hexane measurements at different temperatures. Our program is based on an iterative procedure, and our fits prove that it performs as good as LT 9.0.
Introduction of total variation regularization into filtered backprojection algorithm
L. Raczyński, W. Wiślicki, K. Klimaszewski, W. Krzemień, P. Kowalski, R. Shopa, P. Białas, C. Curceanu, E. Czerwiński, K. Dulski A. Gajos, B. Głowacz, M. Gorgol, B. Hiesmayr, B. Jasińska, D. Kisielewska-Kamińska, G. Korcyl, T. Kozik, N. Krawczyk, E. Kubicz, M. Mohammed, M. Pawlik-Niedźwiecka, S. Niedźwiecki, M. Pałka, Z. Rudy, N.G. Sharma, S. Sharma, M. Silarski, M. Skurzok, A. Wieczorek, B. Zgardzińska, M. Zieliński, P. Moskal
abstract
In this paper we extend the state-of-the-art filtered backprojection (FBP) method with application of the concept of Total Variation regularization. We compare the performance of the new algorithm with the most common form of regularizing in the FBP image reconstruction via apodizing functions. The methods are validated in terms of cross-correlation coefficient between reconstructed and real image of radioactive tracer distribution using standard Derenzo-type phantom. We demonstrate that the proposed approach results in higher cross-correlation values with respect
to the standard FBP method.
Time calibration of the J-PET detector
M. Skurzok, M. Silarski, D. Alfs, P. Bialas, Shivani, C. Curceanu , E. Czerwinski , K. Dulski , A. Gajos, B. G lowacz , M. Gorgol, B. C. Hiesmayr, B. Jasinska, D. Kisielewska, G. Korcyl, P. Kowalski, T. Kozik , N. Krawczyk, W. Krzemien, E. Kubicz , M. Mohammed, M. Pawlik-Niedzwiecka, S. Niedzwiecki, M. Palka, L. Raczynski , J. Raj, Z. Rudy, N. G. Sharma, S. Sharma , R. Y. Shopa , A. Wieczorek, W. Wislicki , B. Zgardzinska, M. Zielinski, P. Moskal
abstract
The Jagiellonian Positron Emission Tomograph (J-PET) project carried out in the Institute of Physics of the Jagiellonian University is focused on construction and tests of the first prototype of PET scanner for medical diagnostic which allows for the simultaneous 3D imaging of the whole human body using organic scintillators. The J-PET prototype consists of 192 scintillator strips forming three cylindrical layers which are optimized for the detection of photons from the electron-positron annihilation with high time- and high angular-resolutions. In this article we present time calibration and synchronization of the whole J-PET detection system by irradiating each single detection module with a 22Na source and a small detector providing common reference time for synchronization of all the modules.
Novel scintillating material 2-(4-styrylphenyl)benzoxazole for the fully digital and MRI compatible J-PET tomograph based on plastic scintillators
A. Wieczorek, K. Dulski, Sz. Niedźwiecki, D. Alfs, P. Białas, C. Curceanu, E. Czerwiński, A. Danel, A. Gajos, B. Głowacz, M. Gorgol, B. Hiesmayr, B. Jasińska, K. Kacprzak, D. Kamińska, Ł. Kapłon, A. Kochanowski, G. Korcyl, P. Kowalski, T. Kozik, W. Krzemień, E. Kubicz, M. Kucharek, M. Mohammed, M. Pawlik-Niedźwiecka, M. Pałka, L. Raczyński, Z. Rudy, O. Rundel, N. G. Sharma, M. Silarski, T. Uchacz, W. Wiślicki, B. Zgardzińska, M. Zieliński, P. Moskal
abstract
A novel
plastic
scintillator
is developed
for
the
application
in the
digital
positron
emission
tomography
(PET).
The
novelty
of the
concept
lies
in application
of the
2-(4-styrylphenyl)
benzoxazole
as
a wavelength
shifter.
The
substance
has
not
been
used
as
scintillator
dop-
ant
before.
A dopant
shifts
the
scintillation
spectrum
towards
longer
wavelengths
making
it
more
suitable
for
applications
in scintillators
of long
strips
geometry
and
light
detection
with
digital
silicon
photomultipliers.
These
features
open
perspectives
for
the
construction
of the
cost-effective
and
MRI-compatib
le PET
scanner
with
the
large
field
of view.
In this
article
we
present
the
synthesis
method
and
characterize
performance
of the
elaborated
scintillator
by
determining
its
light
emission
spectrum,
light
emission
efficiency,
rising
and
decay
time
of
the
scintillation
pulses
and
resulting
timing
resolution
when
applied
in the
positron
emission
tomography.
The
optimal
concentratio
n of the
novel
wavelength
shifter
was
established
by
maximizing
the
light
output
and
it was
found
to be
0.05
?
for
cuboidal
scintillator
with
dimen-
sions
of 14
mm
x 14
mm
x 20
mm.
Commissioning of the J-PET Detector for Studies of Decays of Positronium Atoms
E. Czerwiński, K. Dulski, P. Białas, C. Curceanu, A. Gajos, B. Głowacz, M. Gorgol, B.C. Hiesmayr, B. Jasińska, D. Kisielewska, G. Korcyl, P. Kowalski, T. Kozik, N. Krawczyk, W. Krzemień, E. Kubicz, M. Mohammed, Sz. Niedźwiecki, M. Pałka, M. Pawlik-Niedźwiecka, L. Raczyński, Z. Rudy, N.G. Sharma, S. Sharma, R.Y. Shopa, M. Silarski, M. Skurzok, A. Wieczorek, W. Wiślicki, B. Zgardzińska, M. Zieliński, P. Moskal
abstract
The Jagiellonian Positron Emission Tomograph (J-PET) is a detector for medical imaging of the whole human body as well as for physics studies involving detection of electron?positron annihilation into photons. J-PET has high angular and time resolution, and allows for measurement of spin of the positronium and the momenta and polarization vectors of annihilation quanta. In this article, we present the potential of the J-PET system for the background rejection in the decays of positronium atoms.
J-PET: A New Technology for the Whole-body PET Imaging
S. Niedźwiecki, P. Białas, C. Curceanu, E. Czerwiński, K. Dulski, A. Gajos, B. Głowacz, M. Gorgol, B.C. Hiesmayr, B. Jasińska, Ł. Kapłon, D. Kisielewska-Kamińska, G. Korcyl, P. Kowalski, T. Kozik, N. Krawczyk, W. Krzemień, E. Kubicz, M. Mohammed, M. Pawlik-Niedźwiecka, M. Pałka, L. Raczyński, Z. Rudy, N.G. Sharma, S. Sharma, R.Y. Shopa, M. Silarski, M. Skurzok, A. Wieczorek, W. Wiślicki, B. Zgardzińska, M. Zieliński, P. Moskal
abstract
The Jagiellonian Positron Emission Tomograph (J-PET) is the first PET built from plastic scintillators. J-PET prototype consists of 192 detection modules arranged axially in three layers forming a cylindrical diagnostic chamber with the inner diameter of 85 cm and the axial field-of-view of 50 cm. An axial arrangement of long strips of plastic scintillators, their small light attenuation, superior timing properties, and relative ease of the increase of the axial field-of-view opens promising perspectives for the cost effective construction of the whole-body PET scanner, as well as construction of MR and CT compatible PET inserts. Present status of the development of the J-PET tomograph will be presented and discussed.
Three-dimensional Image Reconstruction in J-PET Using Filtered Back-projection Method
R.Y. Shopa, K. Klimaszewski, P. Kowalski, W. Krzemień, L. Raczyński, W. Wiślicki, P. Białas, C. Curceanu, E. Czerwiński, K. Dulski, A. Gajos, B. Głowacz, M. Gorgol, B. Hiesmayr, B. Jasińska, D. Kisielewska-Kamińska, G. Korcyl, T. Kozik, N. Krawczyk, E. Kubicz, M. Mohammed, M. Pawlik-Niedźwiecka, S. Niedźwiecki, M. Pałka, Z. Rudy, N.G. Sharma, S. Sharma, M. Silarski, M. Skurzok, A. Wieczorek, B. Zgardzińska, M. Zieliński, P. Moskal
abstract
We present a method and preliminary results of the image reconstruction in the Jagiellonian PET tomograph. Using GATE (Geant4 Application for Tomographic Emission), interactions of the 511 keV photons with a cylindrical detector were generated. Pairs of such photons, flying back-to-back, originate from e+e? annihilations inside a 1 mm spherical source. Spatial and temporal coordinates of hits were smeared using experimental resolutions of the detector. We incorporated the algorithm of the 3D Filtered Back Projection, implemented in the STIR and TomoPy software packages, which differ in approximation methods. Consistent results for the Point Spread Functions of ? 5 ÷ 7 mm and ? 9 ÷ 20 mm were obtained, using STIR, for transverse and longitudinal directions, respectively, with no time-of-flight information included.
Drift Chamber Calibration and Track Reconstruction in the P349 Antiproton Polarization Experiment
D. Alfs, B. Głowacz, P. Moskal, M. Zieliński, D. Grzonka, F. Hauenstein, K. Kilian, D. Lersch, J. Ritman, T. Sefzick, W. Oelert, M. Diermaier, E. Widmann, J. Zmeskal, M. Wolke, P. Nadel-Turonski, M. Carmignotto, T. Horn, H. Mkrtchyan, A. Asaturyan, A. Mkrtchyan, V. Tadevosyan, S. Zhamkochyan, S. Malbrunot-Ettenauer, W. Eyrich
abstract
The goal of the P349 experiment is to test whether the antiproton production process can be itself a source of antiproton polarization. In this article, we present the motivation and details of the performed measurement. We report on the status of the analysis focusing mainly on calibration of the drift chambers and 3d track reconstruction.
Human Tissues Investigation Using PALS Technique
B. Jasińska, B. Zgardzińska, G. Chołubek, M. Gorgol, K. Wiktor, K. Wysogląd, P. Białas, C. Curceanu, E. Czerwiński, K. Dulski, A. Gajos, B. Głowacz, B.C. Hiesmayr, B. Jodłowska-Jędrych, D. Kamińska, G. Korcyl, P. Kowalski, T. Kozik, N. Krawczyk, W. Krzemień, E. Kubicz, M. Mohammed, M. Pawlik-Niedźwiecka, S. Niedźwiecki, M. Pałka, L. Raczyński, Z. Rudy, N.G. Sharma, S. Sharma, R. Shopa, M. Silarski, M. Skurzok, A. Wieczorek, H. Wiktor, W. Wiślicki, M. Zieliński, P. Moskal
abstract
Samples of uterine leiomyomatis and normal tissues taken from patients
after surgery were investigated using the Positron Annihilation Lifetime
Spectroscopy (PALS). Significant differences in all PALS parameters
between normal and diseased tissues were observed. For all studied patients,
it was found that the values of the free annihilation and orthopositronium
lifetime are larger for the tumorous tissues than for the healthy
ones. For most of the patients, the intensity of the free annihilation and
ortho-positronium annihilation was smaller for the tumorous than for the
healthy tissues. For the first time, in this kind of studies, the 3gamma fraction
of positron annihilation was determined to describe changes in the tissue
porosity during morphologic alteration.
Multichannel FPGA based MVT system for high precision time (20 ps RMS) and charge measurement
M. Palka, P. Strzempek, G. Korcyl, T. Bednarski, S. Niedzwiecki, P. Bialas, E. Czerwinski, K. Dulski, A. Gajos, B. Glowacz, M. Gorgol, B. Jasinska, D. Kaminska, M. Kajetanowicz, P. Kowalski, T. Kozik, W. Krzemien, E. Kubicz, M. Mohhamed, L. Raczynski, Z. Rudy, O. Rundel, P. Salabura, NG. Sharma, M. Silarski, J. Smyrski, A. Strzelecki, A. Wieczorek, W. Wislicki, M. Zielinski, B. Zgardzinska, P. Moskal
abstract
In this article it is presented an FPGA based Multi-Voltage Threshold (MVT) system which allows of sampling fast signals (1-2 ns rising and falling edge) in both voltage and time domain. It is possible to achieve a precision of time measurement of 20 ps RMS and reconstruct charge of signals, using a simple approach, with deviation from real value smaller than 10%. Utilization of the differential inputs of an FPGA chip as comparators together with an implementation of a TDC inside an FPGA allowed us to achieve a compact multi-channel system characterized by low power consumption and low production costs. This paper describes realization and functioning of the system comprising 192-channel TDC board and a four mezzanine cards which split incoming signals and discriminate them. The boards have been used to validate a newly developed Time-of-Flight Positron Emission Tomography system based on plastic scintillators. The achieved full system time resolution of sigma (TOF) approximate to 68 ps is by factor of two better with respect to the current TOF-PET systems.
Measurement of the omega->pi+pi-pi0 Dalitz plot distribution
P. Adlarson, ..., E. Czerwiński, O. Khreptak, W. Krzemień, P. Moskal, O. Rundel, I. Schätti-Ozerianska, M. Skurzok, M.J. Zieliński, et al.
abstract
Using the production reactions pd->3Heomega and pp->pp omega, the Dalitz plot distribution for the omega->pi+pi-pi0 decay is studied with the WASA detector at COSY, based on a combined data sample of (4.408+-0.042)*10^4 events. The Dalitz plot density is parametrised by a product of the P-wave phase space and a polynomial expansion in the normalised polar Dalitz plot variables Z and phi. For the first time, a deviation from pure P-wave phase space is observed with a significance of 4.1 sigma. The deviation is parametrised by a linear term 1+2 alpha Z, with alpha determined to be +0.147+-0.036, consistent with the expectations of rho-meson-type final-state interactions of the P-wave pion pairs.
Calculation of the time resolution of the J-PET tomograph using kernel density estimation
L. Raczyński, W. Wiślicki, W. Krzemień, P. Kowalski, D. Alfs, T. Bednarski, P. Białas, C. Curceanu, E. Czerwiński, K. Dulski, A. Gajos, B. Głowacz, M. Gorgol, B. Hiesmayr, B. Jasińska, D. Kamińska, G. Korcyl, T. Kozik, N. Krawczyk, E. Kubicz, M. Mohammed, M. Pawlik-Niedźwiecka, S. Niedźwiecki, M. Pałka, Z. Rudy, O. Rundel, N. Gupta-Sharma, M. Silarski, J. Smyrski, A. Strzelecki, A. Wieczorek, B. Zgardzińska, M. Zieliński and P. Moskal
abstract
In this paper we estimate the time resolution of the J-PET scanner built from plastic scintillators. We incorporate the method of signal processing using the Tikhonov regularization framework and the kernel density estimation method. We obtain simple, closed-form analytical formulae for time resolution. The proposed method is validated using signals registered by means of the single detection unit of the J-PET tomograph built from a 30?cm long plastic scintillator strip. It is shown that the experimental and theoretical results obtained for the J-PET scanner equipped with vacuum tube photomultipliers are consistent.
Measurement of gamma quantum interaction point in plastic scintillator with WLS strips
J. Smyrski, D. Alfs, T. Bednarski, P. Białas, E. Czerwiński, K. Dulski, A. Gajos, B. Głowacz, N. Gupta-Sharma, M. Gorgol, B. Jasińska, M. Kajetanowicz, D. Kamińska, G. Korcyl, P. Kowalski, W. Krzemień, N. Krawczyk, E. Kubicz, M. Mohammed, Sz. Niedźwiecki, M. Pawlik-Niedźwiecka, L. Raczyński, Z. Rudy, P. Salabura, M. Silarski, A. Strzelecki, A. Wieczorek, W. Wiślicki, J. Wojnarska, B. Zgardzińska, M. Zieliński, P. Moskal
abstract
The feasibility of measuring the aśxial coordinate of a gamma quantum interaction point in a plastic scintillator
bar via the detection of scintillation photons escaping from the scintillator with an array of wavelength-shifting
(WLS) strips is demonstrated. Using a test set-up comprising a BC-420 scintillator bar and an array of sixteen
BC-482A WLS strips we achieved a spatial resolution of 5 mm (?) for annihilation photons from a 22Na isotope.
The studied method can be used to improve the spatial resolution of a plastic-scintillator-based PET scanner
which is being developed by the J-PET collaboration.
Search for eta-mesic 4He in the dd->3He n pi0 and dd->3He p pi- reactions with the WASA-at-COSY facility
P. Adlarson, ..., E. Czerwiński, O. Khreptak, W. Krzemień, P. Moskal, O. Rundel, I. Schätti-Ozerianska, M. Skurzok, M.J. Zieliński, et al.
abstract
The search for 4He-eta bound states was performed with the WASA-at-COSY facility via the measurement of the excitation function for the dd->3Henpi0 and dd->3Hepi- processes. The deuteron beam momentum was varied continuously between 2.127 GeV/c and 2.422 GeV/c, corresponding to the excess energy for the dd-> 4He eta reaction ranging from Q = -70 MeV to Q = 30 MeV. The luminosity was determined based on the dd-> 3Hen reaction and the quasi-free proton-proton scattering via dd -> ppn_spectator n_spectator reactions. The excitation functions, determined independently for the measured reactions, do not reveal a structure which could be interpreted as a narrow mesic nucleus. Therefore, the upper limits of the total cross sections for the bound state production and decay in dd->(4He-eta)bound->3Henpi0 and dd->(4He-eta)bound->3Hepi- processes were determined taking into account the isospin relation between the both of the considered channels. The results of the analysis depend on the assumptions of the N*(1535) momentum distribution in the anticipated mesic-4He. Assuming, as in the previous works, that this is identical with the distribution of nucleons bound with 20 MeV in 4He, we determined that (for the mesic bound state width in the range
from 5 MeV to 50 MeV) the upper limits at 90% confidence level are about 3 nb and about 6 nb for npi0 and p pi- channels, respectively. However, based on the recent theoretical findings of the N*(1535) momentum distribution in the N* -3He nucleus bound by 3.6 MeV, we find that the WASA-at-COSY detector acceptance decreases and hence the corresponding upper limits are 5 nb and 10 nb for n pi0 and p pi- channels respectively.
J-PET: A Novel TOF -PET scanner using Organic Scintillators
N.G. Sharma, M. Silarski, D. Alfs, T. Bednarski, P. Białas, E. Czerwiński, K. Dulski, A. Gajos, B. Głowacz, M. Gorgol, B. Jasińska, D. Kamińska, G. Korcyl, P. Kowalski, W. Krzemień, N. Krawczyk, E. Kubicz, M. Mohammed, Sz. Niedźwiecki, M. Pawlik-Niedźwiecka, L. Raczyński, Z. Rudy, O. Rundel, A. Wieczorek, W. Wislicki, M. Zieliński, B. Zgardzińska, P. Moskal
abstract
Positron Emission Tomography (PET) is one of the most advanced nuclear medicine imaging techniques that
have potential to identify many diseases (like cancers, heart diseases, neurological disorders and other abnormalities) in vivo in the earliest stages. However, production of PET modalities for covering the whole human body is economically unrealistic when applying the current technologies. In order to achieve a goal of more economical PET scanner with large geometrical acceptance and improved time resolution, the Jagiellonian Positron Emission Tomography (J-PET) Collaboration is realizing a new project aiming at construction of TOF-PET detector using plastic scintillators instead of crystals. Novelty of the J-PET scanner lies in: (i) application of plastic scintillators as well as in (ii) its front-end electronics which allows signal sampling in voltage domain, (iii) a trigger-less data acquisition system, and (iv) the new time and hit-position reconstruction methods. Moreover, the proposed solution enables to increase the axial field-of-view of the tomograph by extending the length of the plastic scintillator strips without changing the number of photomultipliers and electronic channels.
A feasibility study of ortho-positronium decays measurement with the J-PET scanner based on plastic scintillators
D. Kamińska, A. Gajos, E. Czerwiński, D. Alfs, T. Bednarski, P. Białas, C. Curceanu, K. Dulski, B. Głowacz, N. Gupta-Sharma, M. Gorgol, B. C. Hiesmayr, B. Jasińska, G. Korcyl, P. Kowalski, W. Krzemień, N. Krawczyk, E. Kubicz, M. Mohammed, Sz. Niedźwiecki, M. Pawlik-Niedźwiecka, L. Raczyński, Z. Rudy, M. Silarski, A. Wieczorek, W. Wiślicki, B. Zgardzińska, M. Zieliński, P. Moskal
abstract
We present a study of the application of the Jagiellonian Positron Emission Tomograph (J-PET) for the registration of gamma quanta from decays of ortho-positronium (o-Ps). The J-PET is the first positron emission tomography scanner based on organic scintillators in contrast to all current PET scanners based on inorganic crystals. Monte Carlo simulations show that the J-PET as an axially symmetric and high acceptance scanner can be used as a multi-purpose detector well suited to pursue research including e.g. tests of discrete symmetries in decays of ortho-positronium in addition
to the medical imaging. The gamma quanta originating from o-Ps decay interact in the plastic scintillators predominantly via the Compton effect, making the direct measurement of their energy impossible. Nevertheless, it is shown in this paper that the J-PET scanner will enable studies of the o-Ps->3g decays with angular and energy resolution equal to sigma(theta) = 0.4^{circ} and sigma(E) = 4.1 keV, respectively. An order of magnitude shorter decay time of signals from plastic scintillators with respect to the inorganic crystals results not only in better timing properties crucial for the reduction of physical and instrumental background, but also suppresses significantly the pileups, thus enabling compensation of the lower efficiency of the plastic scintillators by performing measurements with higher positron source activities.
Search for an Isospin I =3 Dibaryon
P. Adlarson, ..., E. Czerwiński, O. Khreptak, W. Krzemień, P. Moskal, O. Rundel, I. Schätti-Ozerianska, M. Skurzok, M.J. Zieliński, et al.
abstract
Various theoretical calculations based on QCD or hadronic interactions predict that in addition to the recently observed dibaryon resonance d*(2380) with I(JP)=0(3+) there should also exist a dibaryon resonance with mirrored quantum numbers I(JP)=3(0+). We report here on a search for such a NN-decoupled state in data on the pp -> pp pi+ pi+ pi- pi- reaction.
Determination of the 3gamma Fraction from Positron Annihilation in Mesoporous Materials for Symmetry Violation Experiment with J-PET Scanner
B. Jasińska, M. Gorgol, M. Wiertel, R. Zaleski, D. Alfs, T. Bednarski, P. Białas, E. Czerwiński, K. Dulski, A. Gajos B. Głowacz, D. Kamińska, Ł. Kapłon, G. Korcyl, P. Kowalski, T. Kozik, W. Krzemień, E. Kubicz, M. Mohammed, Sz. Niedźwiecki, M. Pałka, L. Raczyński, Z. Rudy, O. Rundel, N.G. Sharma, M. Silarski, A. Słomski, A. Strzelecki, A. Wieczorek, W. Wiślicki, B. Zgardzińska, M. Zieliński, P. Moskal
abstract
Various mesoporous materials were investigated to choose the best material for experiments requiring high yield of long-lived positronium. We found that the fraction of 3? annihilation determined using ?-ray energy spectra and positron annihilation lifetime spectra (PAL) changed from 20% to 25%. The 3? fraction and o-Ps formation probability in the polymer XAD-4 is found to be the largest. Elemental analysis performed using scanning electron microscope (SEM) equipped with energy-dispersive X-ray spectroscope EDS shows high purity of the investigated materials.
Sampling FEE and Trigger-less DAQ for the J-PET Scanner
G. Korcyl, D. Alfs, T. Bednarski, P. Białas, E. Czerwiński, K. Dulski, A. Gajos, B. Głowacz, B. Jasińska, D. Kamińska Ł. Kapłon, P. Kowalski, T. Kozik, W. Krzemień, E. Kubicz, M. Mohammed, Sz. Niedźwiecki, M. Pałka, M. Pawlik-Niedźwiecka, L. Raczyński, Z. Rudy, O. Rundel, N.G. Sharma, M. Silarski, A. Słomski, K. Stoła, A. Strzelecki, A. Wieczorek, W. Wiślicki, B.K. Zgardzińska, M. Zieliński, P. Moskal
abstract
In this paper, we present a complete Data Acquisition System (DAQ) together with the readout mechanisms for the J-PET tomography scanner. In general, detector readout chain is constructed out of Front-End Electronics (FEE) measurement devices such as Time-to-Digital or Analog-to-Digital Converters (TDCs or ADCs), data collectors and storage. We have developed a system capable for maintaining continuous readout of digitized data without preliminary selection. Such operation mode results in up to 8 Gbps data stream, therefore, it is required to introduce a dedicated module for on-line event building and feature extraction. The Central Controller Module, equipped with Xilinx Zynq SoC and 16 optical transceivers, serves as such true real time computing facility. Our solution for the continuous data recording (trigger-less) is a novel approach in such detector systems and assures that most of the information is preserved on the storage for further, high-level processing. Signal discrimination applies a unique method of using LVDS buffers located in the FPGA fabric.
Beam Profile Investigation of the New Collimator System for the J-PET Detector
E. Kubicz, M. Silarski, A. Wieczorek, D. Alfs, T. Bednarski, P. Białas, E. Czerwiński, A. Gajos, B. Głowacz, B. Jasińska D. Kamińska, G. Korcyl, P. Kowalski, T. Kozik, W. Krzemień, M. Mohammed, I. Moskal, S. Niedźwiecki, M. Pawlik-Niedźwiecka, L. Raczyński, Z. Rudy, A. Strzelecki, W. Wiślicki, M. Zieliński, B. Zgardzińska, P. Moskal
abstract
Jagiellonian Positron Emission Tomograph (J-PET) is a multi-purpose detector which will be used for search for discrete symmetries violations in the decays of positronium atoms and for investigations with positronium atoms in life-sciences and medical diagnostics. In this article, we present three methods for determination of the beam profile of collimated annihilation gamma quanta. Precise monitoring of this profile is essential for time and energy calibration of the J-PET detector and for the determination of the library of model signals used in the hit-time and hit-position reconstruction. We have shown that usage of two lead bricks with dimensions of 5 × 10 × 20 cm3 enables to form a beam of annihilation quanta with Gaussian profile characterized by 1 mm FWHM. Determination of this characteristic is essential for designing and construction the collimator system for the 24-module J-PET prototype. Simulations of the beam profile for different collimator dimensions were performed. This allowed us to choose optimal collimation system in terms of the beam profile parameters, dimensions and weight of the collimator taking into account the design of the 24-module J-PET detector.
Scatter Fraction of the J-PET Tomography Scanner
P. Kowalski, W. Wiślicki, L. Raczyński, D. Alfs, T. Bednarski, P. Białas, E. Czerwiński, A. Gajos, B. Głowacz, J. Jasińska D. Kamińska, G. Korcyl, T. Kozik, W. Krzemień, E. Kubicz, M. Mohammad, Sz. Niedźwiecki, M. Pałka, M. Pawlik-Niedźwiecka, Z. Rudy, M. Silarski, A. Wieczorek, B. Zgardzińska, M. Zieliński, P. Moskal
abstract
A novel Positron Emission Tomography system, based on plastic scintillators, is being developed by the J-PET Collaboration. In this article, we present the simulation results of the scatter fraction, representing one of the parameters crucial for background studies defined in the NEMA-NU-2-2012 norm. We elaborate an event selection methods allowing to suppress events in which gamma quanta were scattered in the phantom or underwent the multiple scattering in the detector. The estimated scatter fraction for the single-layer J-PET scanner varies from 37% to 53% depending on the applied energy threshold.
Application of the compress sensing theory for improvement of the TOF resolution in a novel J-PET instrument
L. Raczyński, P. Moskal, P. Kowalski, W. Wiślicki, T. Bednarski, P. Białas, E. Czerwiński, A. Gajos, Ł. Kapłon, A. Kochanowski, G. Korcyl, J. Kowal, T. Kozik, W. Krzemień, E. Kubicz, Sz. Niedźwiecki, M. Pałka, Z. Rudy, P. Salabura, N. Gupta-Sharma, M. Silarski, A. Słomski, J. Smyrski, A. Strzelecki, A. Wieczorek, M. Zieliński, N. Zoń
abstract
Trilateration-based reconstruction of ortho-positronium decays into three photons with the J-PET detector
A. Gajos, D. Kamińska, E. Czerwiński, D. Alfs, T. Bednarski, P. Białas, B. Głowacz, M. Gorgol, B. Jasińska, Ł. Kapłon, G. Korcyl, P. Kowalski, T. Kozik, W. Krzemień, E. Kubicz, M. Mohammed, Sz. Niedźwiecki, M. Pałka, M. Pawlik-Niedźwiecka, L. Raczyński, Z. Rudy, O. Rundel, N.G. Sharma, M. Silarski, A. Słomski, A. Strzelecki, A. Wieczorek, W. Wiślicki, B. Zgardzińska, M. Zieliński, P. Moskal
abstract
This work reports on a new reconstruction algorithm allowing us to reconstruct the decays of ortho-positronium atoms into three photons using the places and times of photons recorded in the detector. The method is based on trilateration and allows for a simultaneous reconstruction of both location and time of the decay. Results of resolution tests of the new reconstruction in the J-PET detector based on Monte Carlo simulations are presented, which yield a spatial resolution at the level of 2 cm (FWHM) for X and Y and at the level of 1 cm (FWHM) for Z available with the present resolution of J-PET after application of a kinematic fit. Prospects of employment of this method for studying angular correlations of photons in decays of polarized ortho-positronia for the needs of tests of CP and CPT discrete symmetries are also discussed. The new reconstruction method allows for discrimination of background from random three-photon coincidences as well as for application of a novel method for determination of the linear polarization of ortho-positronium atoms, which is also introduced in this work.
Electron-cooled accumulation of 4 × 10^9 positrons for production and storage of antihydrogen atoms
D. W. Fitzakerley, M. C. George, E. A. Hessels, T. D. G. Skinner, C. H. Storry, M. Weel, G. Gabrielse, C. D. Hamley, N. Jones, K. Marable, E. Tardiff, D. Grzonka, W. Oelert and M. Zieliński (ATRAP Collaboration)
abstract
Four billion positrons (e+) are accumulated in a Penning?Ioffe trap apparatus at 1.2 K and <6 × 10?17 Torr. This is the largest number of positrons ever held in a Penning trap. The e+ are cooled by collisions with trapped electrons (e?) in this first demonstration of using e? for efficient loading of e+ into a Penning trap. The combined low temperature and vacuum pressure provide an environment suitable for antihydrogen production, and long antimatter storage times, sufficient for high-precision tests of antimatter gravity and of CPT.
Large numbers of cold positronium atoms created in laser-selected Rydberg states using resonant charge exchange
R. McConnell, G. Gabrielse, W. S. Kolthammer, P. Richerme, A. Müllers, J. Walz, D. Grzonka, M. Zieliński, D. Fitzakerley, M. C. George, E. A. Hessels, C. H. Storry and M. Weel (ATRAP Collaboration)
abstract
Lasers are used to control the production of highly excited positronium atoms (Ps*). The laser light excites Cs atoms to Rydberg states that have a large cross section for resonant charge-exchange collisions with cold trapped positrons. For each trial with 30 million trapped positrons, more than 700 000 of the created Ps* have trajectories near the axis of the apparatus, and are detected using Stark ionization. This number of Ps* is 500 times higher than realized in an earlier proof-of-principle demonstration (2004 Phys. Lett. B 597 257). A second charge exchange of these near-axis Ps* with trapped antiprotons could be used to produce cold antihydrogen, and this antihydrogen production is expected to be increased by a similar factor.
Time resolution of the plastic scintillator strips with matrix photomultiplier readout for J-PET tomograph
P. Moskal, O. Rundel, D. Alfs, T. Bednarski, P. Białas, E. Czerwiński, A. Gajos, K. Giergiel, M. Gorgol, B. Jasińska, D. Kamińska, Ł. Kapłon, G. Korcyl, P. Kowalski, T. Kozik, W. Krzemień, E. Kubicz, Sz. Niedźwiecki, M. Pałka, L. Raczyński, Z. Rudy, N.G. Sharma, A. Słomski, M. Silarski, A. Strzelecki, A. Wieczorek, W. Wiślicki, P. Witkowski, M. Zieliński, N. Zoń
abstract
Recent tests of a single module of the Jagiellonian Positron Emission
Tomography system (J-PET) consisting of 30 cm long plastic scintillator
strips have proven its applicability for the detection of annihilation quanta
(0.511 MeV) with a coincidence resolving time (CRT) of 0.266 ns. The
achieved resolution is almost by a factor of two better with respect to the
current TOF-PET detectors and it can still be improved since, as it is shown
in this article, the intrinsic limit of time resolution for the determination of
time of the interaction of 0.511 MeV gamma quanta in plastic scintillators
is much lower. As the major point of the article, a method allowing to
record timestamps of several photons, at two ends of the scintillator strip,
by means of matrix of silicon photomultipliers (SiPM) is introduced. As a
result of simulations, conducted with the number of SiPM varying from 4 to 42, it is shown that the improvement of timing resolution saturates with
the growing number of photomultipliers, and that the 2×5 configuration at
two ends allowing to read twenty timestamps, constitutes an optimal solution.
The conducted simulations accounted for the emission time distribution,
photon transport and absorption inside the scintillator, as well as quantum
efficiency and transit time spread of photosensors, and were checked based on
the experimental results. Application of the 2×5 matrix of SiPM allows for
achieving the coincidence resolving time in positron emission tomography of
0.170 ns for 15 cm axial field-of-view (AFOV) and 0.365 ns for 100 cm
AFOV. The results open perspectives for construction of a cost-effective TOFPET
scanner with significantly better TOF resolution and larger AFOV with
respect to the current TOF-PET modalities.
Overview of the software architecture and data flow for the J-PET tomography device
W. Krzemień, D. Alfs, P. Białas, E. Czerwiński, A. Gajos, B. Głowacz, B. Jasińska, D. Kamińska, G. Korcyl, P. Kowalski, T. Kozik, E. Kubicz, Sz. Niedźwiecki, M. Pawlik-Niedźwiecka, L. Raczyński, Z. Rudy, M. Silarski, A. Strzelecki, A. Wieczorek, W. Wiślicki, M. Zieliński, P. Moskal
abstract
Modern TOF-PET scanner systems require high-speed computing resources for efficient data processing, monitoring and image reconstruction. In this article we present the data flow and software architecture for the novel TOF-PET scanner developed by the J-PET collaboration. We discuss the data acquisition system, reconstruction framework and some image reconstruction issues. Also, the concept of computing outside hospitals in the remote centers such as 'Swierk Computing Centre in Poland is presented
Potential of the J-PET Detector for Studies of Discrete Symmetries in Decays of Positronium Atom - a Purely Leptonic System
P. Moskal, D. Alfs, T. Bednarski, P. Białas, E. Czerwinski, C. Curceanu, A. Gajos, B. Głowacz, M. Gorgol, B.C. Hiesmayr, B. Jasinska, D. Kaminska, G. Korcyl, P. Kowalski, T. Kozik, W. Krzemien , N. Krawczyk, E. Kubicz, M. Mohammed, Sz. Niedzwiecki, M. Pawlik-Niedzwiecka, L. Raczynski, Z. Rudy, M. Silarski, A. Wieczorek, W. Wislicki, M. Zielinski
abstract
The Jagiellonian Positron Emission Tomograph (J-PET) was constructed
as a prototype of the cost-effective scanner for the simultaneous
metabolic imaging of the whole human body. Being optimized for the detection
of photons from the electron?positron annihilation with high timeand
high angular-resolution, it constitutes a multi-purpose detector providing
new opportunities for studying the decays of positronium atoms.
Positronium is the lightest purely leptonic object decaying into photons.
As an atom bound by a central potential, it is a parity eigenstate, and
as an atom built out of an electron and an anti-electron, it is an eigenstate
of the charge conjugation operator. Therefore, the positronium is
a unique laboratory to study discrete symmetries whose precision is limited,
in principle, by the effects due to the weak interactions expected at the level of (10????14) and photon?photon interactions expected at the
level of (10????9). The J-PET detector enables to perform tests of discrete
symmetries in the leptonic sector via the determination of the expectation
values of the discrete-symmetries-odd operators, which may be constructed
from the spin of ortho-positronium atom and the momenta and polarization
vectors of photons originating from its annihilation. In this article, we
present the potential of the J-PET detector to test the C, CP, T and CPT
symmetries in the decays of positronium atoms.
Measurement of the vec{n} p->d pi0 pi0 Reaction with Polarized Beam in the Region of the d*(2380) Resonance
P. Adlarson, ..., E. Czerwiński, M. Hodana, J. Klaja, W. Krzemień, P. Moskal, I. Ozerianska, O. Rundel, M. Skurzok, M. Zieliński et al.
abstract
We report on a high-statistics measurement of the most basic double pionic fusion reaction vec{n}p -> dpi0pi0 over the energy region of the d*(2380) resonance by use of a polarized deuteron beam and observing the double fusion reaction in the quasifree scattering mode. The measurements were performed with the WASA detector setup at COSY. The data reveal substantial analyzing powers and confirm conclusions about the d? resonance obtained from unpolarized measurements. We also confirm the previous unpolarized data obtained under complementary kinematic conditions.
J-PET: A Novel TOF-PFT Detector based on Plastic Scintillators
P. Moskal, D. Alfs, T. Bednarski, P. Bialas, C. Curceanu, E. Czerwinski, K. Dulski, A. Gajos, B. Glowacz, M. Gorgol, B. Hiesmayr, B. Jasinska, D. Kaminska, G. Korcyl, P. Kowalski, T. Kozik, W. Krzemien, E. Kubicz, M. Mohammed, M. Pawlik-Niedzwiecka, S. Niedzwiecki, M. Palka, L. Raczynski, Z. Rudy, O. Rundel, NG. Sharma, M. Silarski, J. Smyrski, A. Strzelecki, A. Wieczorek, W. Wislicki, B. Zgardzinska, M. Zielinski
abstract
The purpose of the reported research is the elaboration of the method for construction of the cost-effective whole body single-bed positron emission tomography scanner enabling simultaneous PET/CT and PET/MR imaging The Jagiellonian Positron Emission Tomograph (J-PET) is built out of 192 scintillator strips arranged axially in three layers forming a cylindrical diagnostic chamber with the diameter of 85 cm and axial field of-view of 50 cm. The novelty of the concept lies in employing long strips of plastic scintillators instead of crystals as detectors of the annihilation quanta, and in using the timing of signals instead of their amplitudes for the reconstruction of Lines-of Response. To take advantage of the superior timing properties of plastic scintillators a novel multi-voltage-threshold front-end electronics was developed allowing for sampling of signals in a voltage domain. An axial arrangement of long strips of plastic scintillators, and their small light attenuation allows us to make a TOE-PET scanner with a long axial field-of-view. The presented solution opens unique possibilities of combining PET with CT and PET with MRI for scanning the same part of a patient at the same time with both methods. The relative ease of the cost effective increase of the axial field-of-view makes the J-PET tomograph competitive with respect to the current commercial PET scanners as regards sensitivity and time resolution.
Statistical Analysis of Time Resolution of the J-PET Scanner
L. Raczynski, W. Wislicki, P. Kowalski, W. Krzemien, D. Alfs, T. Bednarski, P. Bialas, C. Curceanu, E. Czerwinski, K. Dulski, A. Gajos, B. Glowacz, M. Gorgol, B. Hiesmayr, B. Jasinska, D. Kaminska, G. Korcyl, T. Kozik, N. Krawczyk, E. Kubicz, M. Mohammed, M. Pawlik-Niedzwiecka, S. Niedzwiecki, M. Palka, Z. Rudy, O. Rundel, NG. Sharma, M. Silarski, J. Smyrski, A. Strzelecki, A. Wieczorek, B. Zgardzinska, M. Zielinski, P. Moskal
abstract
The commercial Positron Emission Tomography (PET) scanners use inorganic crystal scintillators for the detection of gamma photons. The Jagiellonian-PET (J-PET) detector exhibits high time resolution due to use of fast plastic scintillators and dedicated electronics circuits. Since the time resolution of PET scanner is influenced by numerous factors, e.g. a type of photomultipliers attached to the scintillators, the optimal selection of components of the J-PET system requires detailed understanding of the method for calculation the time resolution. In this paper we show the idea of this method, based on statistical analysis of the observed signals on the photomultiplier's output. The method is tested using signals registered by means of the single detection module of the J-PET scanner built out from 30 cm long plastic scintillator strips. We investigate two main factors affecting the photon registration probability, photomultipliers quantum efficiency and photomultipliers transit time spread. We demonstrate that the quantum efficiency of photomultipliers represents the most important factor influencing overall performance of the J-PET scanner.
Studies of discrete symmetries in a purely leptonic system using the Jagiellonian Positron Emission Tomograph
P. Moskal, D. Alfs, T. Bednarski, P. Bialas, C. Curceanu, E. Czerwinski, K. Dulski, A. Gajos, B. Glowacz, N. Gupta-Sharma, M. Gorgol, BC. Hiesmayr, B. Jasinska, D. Kaminska, O. Khreptak, G. Korcyl, P. Kowalski, W. Krzemien, N. Krawczyk, E. Kubicz, M. Mohammed, S. Niedzwiecki, M. Pawlik-Niedzwiecka, L. Raczynski, Z. Rudy, M. Silarski, J. Smyrski, A. Wieczorek, W. Wislicki, B. Zgardzinska, M. Zielinski
abstract
Discrete symmetries such as parity (P), charge-conjugation (C) and time reversal (T) are of fundamental importance in physics and cosmology. Breaking of charge conjugation symmetry (C) and its combination with parity (CP) constitute necessary conditions for the existence of the asymmetry between matter and antimatter in the observed Universe. The presently known sources of discrete symmetries violations can account for only a tiny fraction of the excess of matter over antimatter. So far CP and T symmetries violations were observed only for systems involving quarks and they were never reported for the purely leptonic objects. In this article we describe briefly an experimental proposal for the test of discrete symmetries in the decays of positronium atom which is made exclusively of leptons. The experiments are conducted by means of the Jagiellonian Positron Emission Tomograph (J-PET) which is constructed from strips of plastic scintillators enabling registration of photons from the positronium annihilation. J-PET tomograph together with the positronium target system enable to measure expectation values for the discrete symmetries odd operators constructed from (i)spin vector of the ortho-positronium atom, (ii) momentum vectors of photons originating from the decay of positronium, and (iii) linear polarization direction of annihilation photons. Linearly polarized positronium will be produced in the highly porous aerogel or polymer targets, exploiting longitudinally polarized positrons emitted by the sodium Na-22 isotope. Information about the polarization vector of ortho-positronium will be available on the event by event basis and will be reconstructed from the known position of the positron source and the reconstructed position of the ortho-positronium annihilation. In 2016 the first tests and calibration runs are planned, and the data collection with high statistics will commence in the year 2017.
Searches for discrete symmetries violation in ortho-positronium decay using the J-PET detector
D. Kamińska, A. Gajos, E. Czerwiński, T. Bednarski, P. Białas, M. Gorgol, B. Jasińska, Ł. Kapłon, G. Korcyl, P. Kowalski, T. Kozik, W. Krzemień, E. Kubicz, S. Niedźwiecki, M. Pałka, L. Raczyński, Z. Rudy, O. Rundel, N. Gupta-Sharma, M. Silarski, A. Słomski, A. Strzelecki, A. Wieczorek, W. Wiślicki, M. Zieliński, B. Zgardzińska, P. Moskal
abstract
In this paper, we present prospects for using the Jagiellonian positron emission tomograph (J-PET)
detector to search for discrete symmetries violations in a purely leptonic system of the positronium atom. We
discuss tests of CP and CPT symmetries by means of ortho-positronium decays into three photons. No zero
expectation values for chosen correlations between ortho-positronium spin and momentum vectors of photons
would imply the existence of physics phenomena beyond the standard model. Previous measurements resulted
in violation amplitude parameters for CP and CPT symmetries consistent with zero, with an uncertainty of
about 10?3. The J-PET detector allows to determine those values with better precision, thanks to the unique
time and angular resolution combined with a high geometrical acceptance. Achieving the aforementioned is possible
because of the application of polymer scintillators instead of crystals as detectors of annihilation quanta.
Studies of unicellular microorganisms Saccharomyces cerevisiae by means of positron annihilation lifetime spectroscopy
E. Kubicz, B. Jasińska, B. Zgardzińska, T. Bednarski, P. Białas, E. Czerwiński, A. Gajos, M. Gorgol, D. Kamińska, Ł. Kapłon, A. Kochanowski, G. Korcyl, P. Kowalski, T. Kozik, W. Krzemień, S. Niedźwiecki, M. Pałka, L. Raczyński, Z. Rajfur, Z. Rudy, O. Rundel, N. Gupta-Sharma, M. Silarski, A. Słomski, A. Strzelecki, A. Wieczorek, W. Wiślicki, M. Zieliński, P. Moskal
abstract
Results of positron annihilation lifetime spectroscopy (PALS) and microscopic studies on simple microorganisms,
brewing yeasts, are presented. Lifetime of ortho-positronium (o-Ps) were found to change from 2.4 to 2.9 ns
(longer-lived component) for lyophilized and aqueous yeasts, respectively. Also hygroscopicity of yeasts in time was
examined, allowing to check how water ? the main component of the cell ? affects PALS parameters, thus lifetime
of o-Ps were found to change from 1.2 to 1.4 ns (shorter-lived component) for the dried yeasts. The time suffi cient
to hydrate the cells was found below 10 hours. In the presence of liquid water, an indication of reorganization of
yeast in the molecular scale was observed. Microscopic images of the lyophilized, dried, and wet yeasts with best
possible resolution were obtained using inverted microscopy (IM) and environmental scanning electron microscopy
(ESEM) methods. As a result, visible changes to the surface of the cell me mbrane were observed in ESEM images.
Reconstruction of hit time and hit position of annihilation quanta in the J-PET detector usi ng the Mahalanobis distance
N. G. Sharma, M. Silarski, T. Bednarski, P. Białas, E. Czerwiński, A. Gajos, M. Gorgol, B. Jasińska, D. Kamińska, Ł. Kapłon, G. Korcyl, P. Kowalski, T. Kozik, W. Krzemień, E. Kubicz, Sz. Niedźwiecki, M. Pałka, L. Raczyński, Z. Rudy, O. Rundel, A. Słomski, A. Strzelecki, A. Wieczorek, W. Wiślicki, M. Zieliński, B. Zgardzińska, P. Moskal
abstract
The J-PET detector being developed at Jagiellonian University, is a Positron Emission Tomograph composed of the long strips of polymer scintillators. At the same time it is a detector system which will be used for studies of the decays of positronium atoms. The shape of photomultiplier signals depends on the hit-time and hit-position of the gamma quantum. In order to take advantage of this fact a dedicated sampling front-end electronics which enables to sample signals in voltage domain with the time precision of about 20 ps and novel reconstruction method based on the comparison of examined signal with the model signals stored in the library has been developed. As a measure of the similarity we use the Mahalanobis distance. The achievable position and time-resolution depends on number and values of the threshold levels at which the signal is sampled. A reconstruction method, as well as preliminary results are presented and discussed.
PALS investigations of free volumes thermal expansion of J-PET plastic scintillator synthesized in polystyrene matrix
A. Wieczorek, B. Zgardzińska, B. Jasińska, M. Gorgol, T. Bednarski, P. Białas, E. Czerwiński, A. Gajos, D. Kamińska, Ł. Kapłon, A. Kochanowski, G. Korcyl, P. Kowalski, T. Kozik, W. Krzemień, E. Kubicz, Sz. Niedźwiecki, M. Pałka, L. Raczyński, Z. Rudy, O. Rundel, N.G. Sharma, M. Silarski, A. Słomski, A. Strzelecki, W. Wiślicki, M. Zieliński, P. Moskal
abstract
The polystyrene dopped with 2,5-diphenyloxazole as a primary fluor and 2-(4-styrylphenyl)benzoxazole as a wavelength shifter, prepared as a plastic scintillator was investigated using positronium probe in wide range of temperatures from 123 to 423 K. Three structural transitions at 260 K, 283 K and 370 K were found in the material. In the o-Ps intensity dependence on temperature, the significant hysteresis is observed. Heated to 370 K, the material exhibits the o-Ps intensity variations in time.
Processing optimization with parallel computing for the J-PET scanner
W. Krzemień, M. Bała, T. Bednarski, P. Białas, E. Czerwiński, A. Gajos, M. Gorgol, B. Jasińska, D. Kamińska, Ł. Kapłon, G. Korcyl, P. Kowalski, T. Kozik, E. Kubicz, Sz. Niedźwiecki, M. Pałka, L. Raczyński, Z. Rudy, O. Rundel, N.G. Sharma, M. Silarski, A. Słomski, K. Stola, A. Strzelecki, D. Trybek, Anna Wieczorek, W. Wiślicki, M. Zieliński, B. K. Zgardzińska, P. Moskal
abstract
The Jagiellonian-PET (J-PET) collaboration is developing a prototype TOF-PET detector based on long polymer scintillators. This novel approach exploits the excellent time properties of the plastic scintillators, which permit very precise time measurements. The very fast, FPGA-based front-end electronics and the data acquisition system, as well as, low- and high-level reconstruction algorithms were specially developed to be used with the J-PET scanner. The TOF-PET data processing and reconstruction are time and resource demanding operations, especially in case of a large acceptance detector, which works in triggerless data acquisition mode. In this article, we discuss the parallel computing methods applied to optimize the data processing for the J-PET detector. We begin with general concepts of parallel computing and then we discuss several applications of those techniques in the J-PET data processing.
Multiple Scattering and Accidental Coincidences in the J-PET Detector Simulated Using GATE Package
P. Kowalski, P. Moskal, W. Wislicki, L. Raczynski, T. Bednarski, P. Bialas, J. Bulka, E. Czerwinski, A. Gajos, A. Gruntowski, D. Kaminska, L. Kaplon, A. Kochanowski, G. Korcyl, J. Kowal, T. Kozik, W. Krzemien, E. Kubicz, S. Niedzwiecki, M. Palka, Z. Rudy, P. Salabura, NG. Sharma, M. Silarski, A. Slomski, J. Smyrski, A. Strzelecki, A. Wieczorek, I. Wochlik, M. Zielinski, N. Zon
abstract
Novel positron emission tomography system, based on plastic scintillators, is developed by the J-PET collaboration. In order to optimize geometrical configuration of built device, advanced computer simulations are performed. Detailed study is presented of background given by accidental coincidences and multiple scattering of gamma quanta.
A pilot study of the novel J-PET plastic scintillator with 2-(4-styrylphenyl)benzoxazole as a wavelength shifter
A. Wieczorek, P. Moskal, Sz. Niedźwiecki, T. Bednarski, P. Białas, E. Czerwiński, A. Danel, A. Gajos, A. Gruntowski, D. Kamińska, Ł. Kapłon, A. Kochanowski, G. Korcyl, J. Kowal, P. Kowalski, T. Kozik, W. Krzemień, E. Kubicz, M. Molenda, M. Pałka, L. Raczyński, Z. Rudy, O. Rundel, P. Salabura, N.G. Sharma, M. Silarski, A. Słomski, J. Smyrski, A. Strzelecki, T. Uchacz, W. Wiślicki, M. Zieliński, N. Zoń
abstract
For the first time a molecule of 2-(4-styrylphenyl)benzoxazole containing benzoxazole and stilbene groups is applied as a scintillator dopant acting as a wavelength shifter. In this article a light yield of the plastic scintillator, prepared from styrene doped with 2 wt% of 2,5-diphenylbenzoxazole and 0.03 wt% of 2-(4-styrylphenyl)benzoxazole, is determined to be as large as 60% ? 2% of the anthracene light output. There is a potential to improve this value in the future by the optimization of the additives concentrations.
Compressive sensing of signals generated in plastic scintillators in a novel J-PET instrument
L. Raczyński, P. Moskal, P. Kowalski, W. Wiślicki, T. Bednarski, P. Białas, E. Czerwiński, A. Gajos, Ł. Kapłon, A. Kochanowski, G. Korcyl, J. Kowal, T. Kozik, W. Krzemień, E. Kubicz, Sz. Niedźwiecki, M. Pałka, Z. Rudy, O. Rundel, P. Salabura, N.G. Sharma, M. Silarski, A. Słomski, J. Smyrski, A. Strzelecki, A. Wieczorek, M. Zieliński, N. Zoń
abstract
The J-PET scanner, which allows for single bed imaging of the whole human body, is currently under development at the Jagiellonian University. The discussed detector offers improvement of the Time of Flight (TOF) resolution due to the use of fast plastic scintillators and dedicated electronics allowing for sampling in the voltage domain of signals with durations of few nanoseconds. In this paper we show that recovery of the whole signal, based on only a few samples, is possible. In order to do that, we incorporate the training signals into the Tikhonov regularization framework and we perform the Principal Component Analysis decomposition, which is well known for its compaction properties. The method yields a simple closed form analytical solution that does not require iterative processing. Moreover, from the Bayes theory the properties of regularized solution, especially its covariance matrix, may be easily derived. This is the key to introduce and prove the formula for calculations of the signal recovery error. In this paper we show that an average recovery error is approximately inversely proportional to the number of acquired samples.
Analysis framework for the J-PET scanner
W. Krzemień, A. Gajos, A. Gruntowski, K. Stola, D. Trybek, T. Bednarski, P. Białas, E. Czerwiński, D. Kamińska, L. Kapłon, A. Kochanowski, G. Korcyl, J. Kowal, P. Kowalski, T. Kozik, E. Kubicz, P. Moskal, Sz. Niedźwiecki, M. Pałka, L. Raczyński, Z. Rudy, P. Salabura, N. G. Sharma, M. Silarski, A. Słomski, J. Smyrski, A. Strzelecki, A. Wieczorek, W. Wiślicki, M. Zieliński, N. Zoń
abstract
J-PET analysis framework is a flexible, lightweight, ROOT-based software package which provides the tools to develop reconstruction and calibration procedures for PET tomography. In this article we present the implementation of the full data-processing chain in the J-PET framework which is used for the data analysis of the J-PET tomography scanner. The Framework incorporates automated handling of PET setup parameters' database as well as high level tools for building data reconstruction procedures. Each of these components is briefly discussed.
Hit time and hit position reconstruction in the J-PET detector based on a library of averaged model signals
P. Moskal, N.G.Sharma, M.Silarski, T. Bednarski, P. Białas, J. Bułka, E. Czerwiński, A. Gajos, D. Kamińska, L. Kapłon, A. Kochanowski, G. Korcyl, J. Kowal, P. Kowalski, T. Kozik, W. Krzemień, E. Kubicz, Sz. Niedźwiecki, M. Pałka, L. Raczyński, Z. Rudy, O. Rundel, P. Salabura, A. Słomski, J. Smyrski, A. Strzelecki, A. Wieczorek, W. Wiślicki, I. Wochlik, M. Zieliński, N. Zoń
abstract
In this article we present a novel method of hit time and hit position reconstruction in long scintillator detectors. We take advantage of the fact that for this kind of detectors amplitude and shape of registered signals depends strongly on the position where particle hit the detector. The reconstruction is based on determination of the degree of similarity between measured and averaged signals stored in a library for a set of well-defined positions along the scintillator. Preliminary results of validation of the introduced method with experimental data obtained by means of the double strip prototype of the J-PET detector are presented.
GPU accelerated image reconstruction in a two-strip J-PET tomograph
P. Białas, J. Kowal, A. Strzelecki, T. Bednarski, E. Czerwiński, A. Gajos, D. Kamińska, Ł. Kapłon, A. Kochanowski, G. Korcyl, P. Kowalski, T. Kozik, W. Krzemień, E. Kubicz, P. Moskal, Sz. Niedźwiecki, M. Pałka, L. Raczyński, Z. Rudy, O. Rundel, P. Salabura, N.G. Sharma, M. Silarski, A. Słomski, J. Smyrski, A. Wieczorek, W. Wiślicki, M. Zieliński, N. Zoń
abstract
We present a fast GPU implementation of the image reconstruction routine, for a novel two strip PET detector that relies solely on the time of flight measurements.
Determination of the COSY Proton Beam Polarization Using the WASA Detector
I. Schätti-Ozerianska, P. Moskal, M. Zieliński
abstract
The dynamics of ?-meson production and the interaction of ? mesons with nucleons can be studied using the pp ? pp? reaction via measurements of the analyzing power Ay. To this end, we have performed a measurement of the pp ? pp? reaction using the WASA-at-COSY detector, which provides large acceptance and is ?-symmetric. The experiment was carried out for the beam momenta of 2026 MeV/c and 2188 MeV/c. In this article, we present a method and results for the determination of the degree of the beam polarization.
Search for polarization effects in the antiproton production process
D. Grzonka, K. Kilian, J. Ritman, T. Sefzick, W. Oelert, M. Diermaier, E. Widmann, J. Zmeskal, B. Glowacz, P. Moskal, M. Zielinski, M. Wolke, P. Nadel-Turonski, M. Carmignotto, T. Horn, H. Mkrtchyan, A. Asaturyan, A. Mkrtchyan, V. Tadevosyan, S. Zhamkochyan, S. Malbrunot-Ettenauer, W. Eyrich, F. Hauenstein, A. Zink
abstract
For the production of a polarized antiproton beam various methods have been suggested including the possibility that antiprotons may be produced polarized which will be checked experimentally. The polarization of antiprotons produced under typical conditions for antiproton beam preparation will be measured at the CERN/PS. If the production process creates some polarization a polarized antiproton beam could be prepared by a rather simple modification of the antiproton beam facility. The detection setup and the expected experimental conditions are described.
ABC Effect and Resonance Structure in the Double-Pionic Fusion to 3He
P. Adlarson, ..., E. Czerwiński, M. Hodana, W. Krzemień, P. Moskal, I. Ozerianska, M. Skurzok, M. Zielinski, et al.
abstract
Exclusive and kinematically complete measurements of the double pionic fusion to 3He have been performed in the energy region of the so-called ABC effect, which denotes a pronounced low-mass enhancement in the pi pi-invariant mass spectrum. The experiments were carried out with the WASA detector setup at COSY. Similar to the observations in the basic pn->dpi0pi0 reaction and in the dd->4Hepi0pi0 reaction, the data reveal a correlation between the ABC effect and a resonance-like energy dependence in the total cross section. Differential cross sections are well described by the hypothesis of d* resonance formation during the reaction process in addition to the conventional t-channel Delta Delta mechanism. The deduced d* resonance width can be understood from collision broadening due to Fermi motion of the nucleons in initial and final nuclei.
A novel method for the line-of-response and time-of-flight reconstruction in TOF-PET detectors based on a library of synchronized model signals
P. Moskal, N. Zoń, T. Bednarski, P. Białas, E. Czerwiński, A. Gajos, D. Kamińska, Ł. Kapłon, A. Kochanowski, G. Korcyl, J. Kowal, P. Kowalski, T. Kozik, W. Krzemień, E. Kubicz, Sz. Niedźwiecki, M. Pałka, L. Raczyński, Z. Rudy, O. Rundel, P. Salabura, N.G. Sharma, M. Silarski, A. Słomski, J. Smyrski, A. Strzelecki, A. Wieczorek, W. Wiślicki, M. Zieliński
abstract
A novel method of hit time and hit position reconstruction in scintillator detectors is described. The method is based on comparison of detector signals with results stored in a library of synchronized model signals registered for a set of well-defined positions of scintillation points. The hit position is reconstructed as the one corresponding to the signal from the library which is most similar to the measurement signal. The time of the interaction is determined as a relative time between the measured signal and the most similar one in the library. A degree of similarity of measured and model signals is defined as the distance between points representing the measurement- and model-signal in the multi-dimensional measurement space. Novelty of the method lies also in the proposed way of synchronization of model signals enabling direct determination of the difference between time-of-flights (TOF) of annihilation quanta from the annihilation point to the detectors. The introduced method was validated using experimental data obtained by means of the double strip prototype of the J-PET detector and 22Na sodium isotope as a source of annihilation gamma quanta.The detector was built out from plastic scintillator strips with dimensions of 5 mm x 19 mm x 300 mm, optically connected at both sides to photomultipliers,from which signals were sampled by means of the Serial Data Analyzer.Using the introduced method, the spatial and TOF resolution of about 1.3 cm (?) and 125 ps (?) were established, respectively.
Test of a single module of the J-PET scanner based on plastic scintillators
P. Moskal, S. Niedzwiecki, T. Bednarski, E. Czerwinski, L. Kaplon, E. Kubicz, I. Moskal, M. Pawlik-Niedzwiecka, NG. Sharma, M. Silarski, M. Zielinski, N. Zon, P. Bialas, A. Gajos, A. Kochanowski, G. Korcyl, J. Kowal, P. Kowalski, T. Kozik, W. Krzemien, M. Molenda, M. Palka, L. Raczynski, Z. Rudy, P. Salabura, A. Slomski, J. Smyrski, A. Strzelecki, A. Wieczorek, W. Wislicki
abstract
A Time of Flight Positron Emission Tomography scanner based on plastic scintillators is being developed at the Jagiellonian University by the J-PET collaboration. The main challenge of the conducted research lies in the elaboration of a method allowing application of plastic scintillators for the detection of low energy gamma quanta. In this paper we report on tests of a single detection module built out from the BC-420 plastic scintillator strip (with dimensions of 5 x 19 x 300 mm(3)) read out at two ends by Hamamatsu R5320 photomultipliers. The measurements were performed using collimated beam of annihilation quanta from the Ge-68 isotope and applying the Serial Data Analyzer (Lecroy SDA6000A) which enabled sampling of signals with 50 ps intervals. The time resolution of the prototype module was established to be better than 80 ps (sigma) for a single level discrimination. The spatial resolution of the determination of the hit position along the strip was determined to be about 0.93 cm (sigma) for the annihilation quanta. The fractional energy resolution for the energy E deposited by the annihilation quanta via the Compton scattering amounts to sigma(E)/E approximate to 0.044/root E(MeV) and corresponds to the (sigma(E)/E of 7.5% at the Compton edge. (C) 2014 Elsevier B.V. All rights reserved.
Measurement of the np->npi0i0 Reaction in Search for the Recently Observed d*(2380) Resonance
P. Adlarson,..., E. Czerwiński, M. Hodana, W. Krzemień, P. Moskal, I. Ozerianska, M. Skurzok, M. Zielinski, et al.
abstract
Exclusive measurements of the quasi-free np->nppi0pi0 reaction have been performed by means of dp collisions at Td = 2.27 GeV using the WASA detector setup at COSY. Total and differential cross sections have been obtained covering the energy region sqrt_s = (2.35 - 2.46) GeV, which includes the region of the ABC effect and its associated d*(2380) resonance. Adding the d* resonance amplitude to that for the conventional processes leads to a reasonable description of the data. The observed resonance effect in the total cross section is in agreement with the predictions of Faeldt and Wilkin as well Albadajedo and Oset. The ABC effect, {it i.e.} the low-mass enhancement in the pi0pi0-invariant mass spectrum, is found to be very modest - if present at all, which might pose a problem to some of its interpretations.
Neutron-Proton Scattering in the Context of the d*(2380) Resonance
P. Adlarson, ..., E. Czerwiński, M. Hodana, W. Krzemień, P. Moskal, I. Ozerianska, M. Skurzok, M. Zielinski, et al.
abstract
New data on quasifree polarized neutron-proton scattering, in the region of the recently observed d* resonance structure, have been obtained by exclusive and kinematically complete high-statistics measurements with WASA at COSY. This paper details the determination of the beam polarization, checks of the quasifree character of the scattering process, on all obtained Ay angular distributions and on the new partial-wave analysis, which includes the new data producing a resonance pole in the 3D3-3G3 coupled partial waves at (2380+-10-i40+-5) MeV -- in accordance with the d* dibaryon resonance hypothesis. The effect of the new partial-wave solution on the description of total and differential cross section data as well as specific combinations of spin-correlation and spin-transfer observables available from COSY-ANKE measurements at Td = 2.27 GeV is discussed.
Determination of the eta '-Proton Scattering Length in Free Space
E. Czerwinski, P. Moskal, M. Silarski, SD. Bass, D. Grzonka, B. Kamys, A. Khoukaz, J. Klaja, W. Krzemien, W. Oelert, J. Ritman, T. Sefzick, J. Smyrski, A. Taschner, M. Wolke, M. Zielinski
abstract
Taking advantage of both the high mass resolution of the COSY-11 detector and the high energy resolution of the low-emittance proton beam of the cooler synchrotron COSY, we determine the excitation function for the pp --> pp eta' reaction close to threshold. Combining these data with previous results, we extract the scattering length for the eta'-proton potential in free space to be Re(alpha(p eta)') = 0 +/- 0.43 fm and Im(alpha(p eta)') = 0.37(-0.16)(+0.40) fm.
Test of a single module of the J-PET scanner based on plastic scintillators
P. Moskal, Sz. Niedźwiecki, T. Bednarski, E. Czerwiński, Ł. Kapłon, E. Kubicz, I. Moskal, M. Pawlik-Niedźwiecka, N.G. Sharma, M. Silarski, M. Zieliński, N. Zoń, P. Białas, A. Gajos, A. Kochanowski, G. Korcyl, J. Kowal, P. Kowalski, T. Kozik, W. Krzemień, M. Molenda, M. Pałka, L. Raczyński, Z. Rudy, P. Salabura, A. Słomski, J. Smyrski, A. Strzelecki, A. Wieczorek, W. Wiślicki
abstract
Time of Flight Positron Emission Tomography scanner based on plastic scintillators is being developed at the Jagiellonian University by the J-PET collaboration. The main challenge of the conducted research lies in the elaboration of a method allowing application of plastic scintillators for the detection of low energy gamma quanta. In this article we report on tests of a single detection module built out from BC-420 plastic scintillator strip (with dimensions of 5x19x300mm^3) read out at two ends by Hamamatsu R5320 photomultipliers. The measurements were performed using collimated beam of annihilation quanta from the 68Ge isotope and applying the Serial Data Analyzer (Lecroy SDA6000A) which enabled sampling of signals with 50ps intervals. The time resolution of the prototype module was established to be better than 80ps (sigma) for a single level discrimination. The spatial resolution of the determination of the hit position along the strip was determined to be about 0.93cm (sigma) for the annihilation quanta. The fractional energy resolution for the energy E deposited by the annihilation quanta via the Compton scattering amounts to sigma(E)/E = 0.044/sqrt(E[MeV]) and corresponds to the sigma(E)/E of 7.5% at the Compton edge.
Novel method for hit-position reconstruction using voltage signals in plastic scintillators and its application to Positron Emission Tomography
L. Raczyński, P. Moskal, P. Kowalski, W. Wiślicki, T. Bednarski, P. Białas, E. Czerwiński, Ł. Kapłon, A. Kochanowski, G. Korcyl, J. Kowal, T. Kozik, W. Krzemień, E. Kubicz, M. Molenda, I. Moskal, Sz. Niedźwiecki, M. Pałka, M. Pawlik-Niedźwiecka, Z. Rudy, P. Salabura, N.G. Sharma, M. Silarski, A. Słomski, J. Smyrski, A. Strzelecki, A. Wieczorek, M. Zieliński, N. Zoń
abstract
Currently inorganic scintillator detectors are used in all commercial Time of Flight Positron Emission Tomograph (TOF-PET) devices. The J-PET collaboration investigates a possibility of construction of a PET scanner from plastic scintillators which would allow for single bed imaging of the whole human body. This paper describes a novel method of hit-position reconstruction based on sampled signals and an example of an application of the method for a single module with a 30 cm long plastic strip, read out on both ends by Hamamatsu R4998 photomultipliers. The sampling scheme to generate a vector with samples of a PET event waveform with respect to four user-defined amplitudes is introduced. The experimental setup provides irradiation of a chosen position in the plastic scintillator strip with an annihilation gamma quanta of energy 511 keV. The statistical test for a multivariate normal (MVN) distribution of measured vectors at a given position is developed, and it is shown that signals sampled at four thresholds in a voltage domain are approximately normally distributed variables. With the presented method of a vector analysis made out of waveform samples acquired with four thresholds, we obtain a spatial resolution of about 1 cm and a timing resolution of about 80 ps (sigma).
Charge Symmetry Breaking in dd->4Hepi0 with WASA-at-COSY
P. Adlarson, ..., E. Czerwiński, M. Hodana, W. Krzemień, P. Moskal, I. Ozerianska, M. Skurzok, M. Zielinski, et al.
abstract
Charge symmetry breaking (CSB) observables are a suitable experimental tool to examine effects induced by quark masses on the nuclear level. Previous high precision data from TRIUMF and IUCF are currently used to develop a consistent description of CSB within the framework of chiral perturbation theory. In this work the experimental studies on the reaction dd->4He{pi}0 have been extended towards higher excess energies in order to provide information on the contribution of p-waves in the final state. For this, an exclusive measurement has been carried out at a beam momentum of p=1.2 GeV/c using the WASA-at-COSY facility. The total cross section amounts to sigma(tot) = (118 +- 18(stat) +- 13(sys) +- 8(ext)) pb and first data on the differential cross section are consistent with s-wave pion production.
Cross section ratio and angular distributions of the reaction p + d -> (3)He + eta at 48.8 MeV and 59.8 MeV excess energy
P. Adlarson, E. Czerwiński, M. Hodana, W. Krzemień, P. Moskal, I. Ozerianska, M. Skurzok, M. Zielinski, et al.
abstract
We present new data for angular distributions and on the cross section ratio of the p+d -> (3)He + eta reaction at excess energies of Q = 48.8 MeV and Q = 59.8 MeV. The data have been obtained at the WASA-at-COSY experiment (Forschungszentrum Jülich) using a proton beam and a deuterium pellet target. While the shape of obtained angular distributions show only a slow variation with the energy, the new results indicate a distinct and unexpected total cross section fluctuation between Q = 20 MeV and Q = 60 MeV, which might indicate the variation of the production mechanism within this energy interval.
Measurement of the eta -> pi + pi - pi0 Dalitz plot distribution
P. Adlarson,..., E. Czerwiński, M. Hodana, W. Krzemień, P. Moskal, I. Ozerianska, M. Skurzok, M. Zieliński, et al.
abstract
Dalitz plot distribution of the eta-> pi+pi-pi0 decay is determined using a data sample of 1.2*10^7 eta mesons from pd->3He eta reaction at 1 GeV collected by the WASA detector at COSY.
Evidence for a New Resonance from Polarized Neutron-Proton Scattering
P. Adlarson, ..., E. Czerwiński, M. Hodana, J. Klaja, W. Krzemień, P. Moskal, I. Ozerianska, M. Skurzok, M. Zieliński et al.
abstract
Exclusive and kinematically complete high-statistics measurements of quasifree polarized vec_n p scattering have been performed in the energy region of the narrow resonance structure d* with I(JP)=0(3+), M ~2380 MeV/c2 and Gamma 70 MeV observed recently in the double-pionic fusion channels pn->dpi0pi0 and pn->dpi+pi-. The experiment was carried out with the WASA detector setup at COSY having a polarized deuteron beam impinged on the hydrogen pellet target and utilizing the quasifree process d p->np+p_spectator. That way the np analyzing power Ay was measured over a large angular range. The obtained Ay angular distributions deviate systematically from the current SAID SP07 NN partial-wave solution. Incorporating the new Ay data into the SAID analysis produces a pole in the 3D3->3G3 waves as expected from the d* resonance hypothesis.
Determination of the eta prime - proton scattering length in free space
E. Czerwiński, P. Moskal, M. Silarski, S. D. Bass, D. Grzonka, B. Kamys, A. Khoukaz, J. Klaja, W. Krzemień, W. Oelert, J. Ritman, T. Sefzick, J. Smyrski, A. Täschner, M. Wolke, M. Zieliński
abstract
Taking advantage of both the high mass resolution of the COSY--11 detector and the high energy resolution of the low-emittance proton-beam of the Cooler Synchrotron COSY we determine the excitation function for the pp --> pp eta' reaction close-to-threshold. Combining these data with previous results we extract the scattering length for the eta'-proton potential in free space to be Re (a p eta') = 0 +/- 0.43 fm and Im a_(p eta') = 0.37^{+0.40}_{-0.16} fm.
Computing support for advanced medical data analysis and imaging
W. Wiślicki, T. Bednarski, P. Białas, E. Czerwiński, Ł. Kapłon, A. Kochanowski, G. Korcyl, J. Kowal, P. Kowalski, T. Kozik, W. Krzemień, M. Molenda, P. Moskal, S. Niedźwiecki, M. Pałka, M. Pawlik, L. Raczyński, Z. Rudy, P. Salabura, N.G. Sharma, M. Silarski, A. Słomski, J. Smyrski, A. Strzelecki, A. Wieczorek, M. Zieliński, N. Zoń
abstract
We discuss computing issues for data analysis and image reconstruction of PET-TOF medical scanner or other medical scanning devices producing large volumes of data. Service architecture based on the grid and cloud concepts for distributed processing is proposed and critically discussed.
A novel method based solely on FPGA units enabling measurement of time and charge of analog signals in Positron Emission Tomography
M. Pałka, T. Bednarski, P. Białas, E. Czerwiński, Ł. Kapłon, A. Kochanowski, G. Korcyl, J. Kowal, P. Kowalski, T. Kozik, W. Krzemień, M. Molenda, P. Moskal, Sz. Niedźwiecki, M. Pawlik, L. Raczyński, Z. Rudy, P. Salabura, N.G. Sharma, M. Silarski, A. Słomski, J. Smyrski, A. Strzelecki, W. Wiślicki, M. Zieliński, N. Zoń
abstract
This article presents a novel technique for precise measurement of time and charge based solely on FPGA (Field Programmable Gate Array) device and few satellite discrete electronic components used in Positron Emission Tomography (PET). Described approach simplifies electronic circuits, reduces the power consumption, lowers costs, merges front-end electronics with digital electronics and also makes more compact final design. Furthermore, it allows to measure time when analog signals cross a reference voltage at different threshold levels with a very high precision of ? 10ps (rms) and thus enables sampling of signals in a voltage domain.
A novel method for calibration and monitoring of time synchronization of TOF-PET scanners by means of cosmic rays
M. Silarski, E. Czerwiński, T. Bednarski, P. Moskal, P. Białas, Ł. Kapłon, A. Kochanowski, G. Korcyl, J. Kowal, P. Kowalski, T. Kozik, W. Krzemień, M. Molenda, Sz. Niedźwiecki, M. Pałka, M. Pawlik, L. Raczyński, Z. Rudy, P. Salabura, N.G. Sharma, A. Słomski, J. Smyrski, A. Strzelecki, W. Wiślicki, M. Zieliński, N. Zoń
abstract
All of the present methods for calibration and monitoring of TOF-PET scanner detectors utilize radioactive isotopes such as e.g. 22Na or 68Ge, which are placed or rotate inside the scanner. In this article we describe a novel method based on the cosmic rays application to the PET calibration and monitoring methods. The concept allows to overcome many of the drawbacks of the present methods and it is well suited for newly developed TOF-PET scanners with a large longitudinal field of view. The method enables also monitoring of the quality of the scintillator materials and in general allows for the continuous quality assurance of the PET detector performance.
3D PET image reconstruction based on the maximum likelihood estimation method (MLEM) algorithm
A. Słomski, Z. Rudy, T. Bednarski, P. Białas, E. Czerwiński, Ł. Kapłon, A. Kochanowski, G. Korcyl, J. Kowal, P. Kowalski, T. Kozik, W. Krzemień, M. Molenda, P. Moskal, Sz. Niedźwiecki, M. Pałka, M. Pawlik, L. Raczyński, P. Salabura, N. G. Sharma, M. Silarski, J. Smyrski, A. Strzelecki, W. Wiślicki, M. Zieliński, N. Zoń
abstract
A positron emission tomography (PET) scan does not measure an image directly. Instead, a PET scan measures a sinogram at the boundary of the field-of-view that consists of measurements of the sums of all the counts along the lines connecting the two detectors. Because there is a multitude of detectors built in a typical PET structure, there are many possible detector pairs that pertain to the measurement. The problem is how to turn this measurement into an image (this is called imaging). Significant improvement in PET image quality was achieved with the introduction of iterative reconstruction techniques. This was realized approximately 20 years ago (with the advent of new powerful computing processors). However, three-dimensional imaging still remains a challenge. The purpose of the image reconstruction algorithm is to process this imperfect count data for a large number (many millions) of lines of response and millions of detected photons to produce an image showing the distribution of the labeled molecules in space.
Trigger-less and reconfigurable data acquisition system for positron emission tomography
G. Korcyl, P. Moskal, T. Bednarski, P. Białas, E. Czerwiński, Ł. Kapłon, A. Kochanowski, J. Kowal, P. Kowalski, T. Kozik, W. Krzemień, M. Molenda, Sz. Niedźwiecki, M. Pałka, M. Pawlik, L. Raczyński, Z. Rudy, P. Salabura, N. G. Sharma, M. Silarski, A. Słomski, J. Smyrski, A. Strzelecki, W. Wiślicki, M. Zieliński, N. Zoń
abstract
This article is focused on data acquisition system (DAQ) designed especially to be used in positron emission tomography (PET) or single-photon emission computed tomography. The system allows for continuous registration of analog signals during measurement. It has been designed to optimize registration and processing of the information carried by signals from the detector system in PET scanner. The processing does not require any rejection of data with a trigger system. The proposed system possesses also an ability to implement various data analysis algorithms that can be performed in real time during data collection.
Determination of the map of efficiency of the Jagiellonian Positron Emission Tomograph (J-PET) detector with the GATE package
P. Kowalski, L. Raczyński, T. Bednarski, P. Białas, E. Czerwiński, K. Giergiel, Ł. Kapłon, A. Kochanowski, G. Korcyl, J. Kowal, T. Kozik, W. Krzemień, M. Molenda, I. Moskal, P. Moskal, Sz. Niedźwiecki, M. Pałka, M. Pawlik-Niedźwiecka, Z. Rudy, P. Salabura, N.G. Sharma, M. Silarski, A. Słomski, J. Smyrski, A. Strzelecki, K. Szymański, W. Wiślicki, P. Witkowski, M. Zieliński, N. Zoń
abstract
A novel PET detector consisting of strips of polymer scintillators is being developed by the J-PET Collaboration. The map of efficiency and the map of geometrical acceptance of the 2-strip J-PET scanner are presented. Map of efficiency was determined using the Monte Carlo simulation software GATE based on GEANT4. Both maps were compared using method based on the chi2 test.
Plastic scintillators for positron emission tomography obtained by the bulk polymerization method
Ł. Kapłon, A. Kochanowski, M. Molenda, P. Moskal, A. Wieczorek, T. Bednarski, P. Białas, E. Czerwiński, G. Korcyl, J. Kowal, P. Kowalski, T. Kozik, W. Krzemień, Sz. Niedźwiecki, M. Pałka, M. Pawlik, L. Raczyński, Z. Rudy, P. Salabura, N. G. Sharma, M. Silarski, A. Słomski, J. Smyrski, A. Strzelecki, W. Wiślicki, M. Zieliński, N. Zoń
abstract
This paper describes three methods regarding the production of plastic scintillators. One method appears to be suitable for the manufacturing of plastic scintillators, revealing properties which fulfill the requirements of novel positron emission tomography scanners based on plastic scintillators. The key parameters of the manufacturing process are determined and discussed.
J-PET analysis framework for the prototype TOF-PET detector
W. Krzemień, M. Silarski, K. Stola, D. Trybek, T. Bednarski, P. Białas, E. Czerwiński, Ł. Kapłon, A. Kochanowski, G. Korcyl, J. Kowal, P. Kowalski, T. Kozik, M. Molenda, P. Moskal, Sz. Niedźwiecki, M. Pałka, M. Pawlik, L. Raczyński, Z. Rudy, P. Salabura, N.G. Sharma, A. Słomski, J. Smyrski, A. Strzelecki, W. Wiślicki, M. Zieliński, N. Zoń
abstract
Novel TOF-PET scanner solutions demand, apart from the state of the art detectors, software for fast processing of the gathered data, monitoring of the whole scanner and reconstruction of the PET image. In this article we present an analysis framework for the novel STRIP-PET scanner developed by the J-PET collaboration in the Institute of Physics of the Jagiellonian University. This software is based on the ROOT package used in many particle physics experiments.
Database and data structure for the novel TOF-PET detector developed for J-PET project
E. Czerwiński, M. Zieliński, T. Bednarski, P. Białas, Ł. Kapłon, A. Kochanowski, G. Korcyl, J. Kowal, P. Kowalski, T. Kozik, W. Krzemień, E. Kubicz, M. Molenda, P. Moskal, Sz. Niedźwiecki, M. Pałka, M. Pawlik, L. Raczyński, Z. Rudy, P. Salabura, N. G. Sharma, M. Silarski, A. Słomski, J. Smyrski, A. Strzelecki, A. Wieczorek, W.Wiślicki, N. Zoń
abstract
The complexity of the hardware and the amount of data collected during the PET imaging process require application of modern methods of efficient data organization and processing. In this article we will discuss the data structures and the flow of collected data from the novel TOF-PET medical scanner which is being developed at the Jagiellonian University. The developed data format reflects: registration process of the gamma quanta emitted from positron-electron annihilation, Front-End Electronic (FEE) structure and required input information for the image reconstruction. In addition, the system database fulfills possible demands of the evolving J-PET project.
Calibration of photomultipliers gain used in the J-PET detector
T. Bednarski, E. Czerwiński, P. Moskal, P. Białas, K. Giergiel, Ł. Kapłon, A. Kochanowski, G. Korcyl, J. Kowal, P. Kowalski, T. Kozik, W. Krzemień, M. Molenda, I. Moskal, Sz. Niedźwiecki, M. Pałka, M. Pawlik, L. Raczyński, Z. Rudy, P. Salabura, N.G. Sharma, M. Silarski, A. Słomski, J. Smyrski, A. Strzelecki, K. Szymański, W. Wiślicki, P. Witkowski, M. Zieliński, N. Zoń
abstract
Photomultipliers are commonly used in commercial PET scanner as devices which convert light produced in scintillator by gamma quanta from positron-electron annihilation into electrical signal. For proper analysis of obtained electrical signal, a photomultiplier gain curve must be known, since gain can be significantly different even between photomultipliers of the same model. In this article we describe single photoelectron method used for photomultipliers calibration applied for J-PET scanner, a novel PET detector being developed at the Jagiellonian University. Description of calibration method, an example of calibration curve and gain of few R4998 Hamamatsu photomultipliers are presented.
Study of the eta meson production with polarized proton beam
M. Hodana, P. Moskal, I. Ozerianska, M. Zieliński
abstract
The pp-> pp eta reaction was investigated at excess energies of 15 MeV and 72 MeV using the azimuthally symmetric WASA detector and a polarized proton beam of the Cooler Synchrotron COSY. The aim of the studies is the determination of partial wave contributions to the production process of the eta meson in nucleon-nucleon collisions. Here we present preliminary results of the extraction of the position of the interaction region with respect to the WASA detector and preliminary results on the degree of polarization of the COSY proton beam used in the experiment.
List-mode reconstruction in 2D strip PET
P. Białas, J. Kowal, A. Strzelecki, T. Bednarski, E. Czerwiński, K. Giergiel, Ł. Kapłon, A. Kochanowski, G. Korcyl, P. Kowalski, T. Kozik, W. Krzemień, M. Molenda, I. Moskal, P. Moskal, S. Niedźwiecki, M. Pałka, M. Pawlik, L. Raczyński, Z. Rudy, P. Salabura, N.G. Sharma, M. Silarski, A. Słomski, J. Smyrski, K. Szymański, W. Wiślicki, P. Witkowski, M. Zieliński, N. Zoń
abstract
Using a theory of list-mode maximum likelihood
expectation-maximization (MLEM) algorithm, in this contribution,
we present a derivation of the system response
kernel for a novel positron emission tomography (PET)
detector based on plastic scintillators.
Simulations of gamma quanta scattering in a single module of the J-PET detector
K. Szymański, P. Moskal, T. Bednarski, P. Białas, E. Czerwiński, K. Giergiel, Ł. Kapłon, A. Kochanowski, G. Korcyl, J. Kowal, P. Kowalski, T. Kozik, W. Krzemień, M. Molenda, I. Moskal, Sz. Niedźwiecki, M. Pałka, M. Pawlik, L. Raczyński, Z. Rudy, P. Salabura, N.G. Sharma, M. Silarski, A. Słomski, J. Smyrski, A. Strzelecki, P. Witkowski, W. Wiślicki, M. Zieliński, N. Zoń
abstract
This article describes simulations of scattering of annihilation gamma quanta in a strip of plastic scintillator. Such strips constitute basic detection modules in a newly proposed Positron Emission Tomography which utilizes plastic scintillators instead of inorganic crystals. An algorithm simulating chain of Compton scatterings was elaborated and series of simulations have been conducted for the scintillator strip with the cross section of 5 mm x 19 mm. Obtained results indicate that secondary interactions occur only in the case of about 8% of events and out of them only 25% take place in the distance larger than 0.5 cm from the primary interaction. It was also established that light signals produced at primary and secondary interactions overlap with the delay which distribution is characterized by FWHM of about 40 ps.
Application of WLS strips for position determination in Strip PET tomograph based on plastic scintillators
J. Smyrski, P. Moskal, T. Bednarski, P. Białas, E. Czerwiński, Ł. Kapłon, A. Kochanowski, G. Korcyl, J. Kowal, P. Kowalski, T. Kozik, W. Krzemień, M. Molenda, Sz. Niedźwiecki, M. Pałka, M. Pawlik, L. Raczyński, Z. Rudy, P. Salabura, N.G. Sharma, M. Silarski, A. Słomski, A. Strzelecki, W. Wiślicki, M. Zieliński, N. Zoń
abstract
A method of determination of a gamma quantum absorption point in a plastic scintillator block using a matrix of wavelength-shifting (WLS) strips is proposed. Application of this method for improvement of position resolution in newly proposed PET detectors based on plastic scintillators is presented. The method enables to reduce parallax errors in reconstruction of images which occurs in the presently used Positron Emission Tomography scanners.
Measurement of the pn->pp pi0pi- Reaction in Search for the Recently Observed Resonance Structure in dpi0pi0 and dpi+pi-systems
P. Adlarson, ..., E. Czerwiński, M. Hodana, J. Klaja, W. Krzemień, P. Moskal, I. Ozerianska, M. Skurzok, M. Zieliński et al.
abstract
Exclusive measurements of the quasi-free $pn o pppi^0pi^-$ reaction have been performed by means of $pd$ collisions at $T_p$ = 1.2 GeV using the WASA detector setup at COSY. Total and differential cross sections have been obtained covering the energy region $sqrt s$ = (2.35 - 2.46) GeV, which includes the region of the ABC effect and its associated resonance structure. No ABC effect, {it i.e.} low-mass enhancement is found in the $pi^0pi^-$-invariant mass spectrum -- in agreement with the constraint from Bose statistics that the isovector pion pair can not be in relative s-wave. At the upper end of the covered energy region $t$-channel processes for Roper, $Delta(1600)$ and $DeltaDelta$ excitations provide a reasonable description of the data, but at low energies the measured cross sections are much larger than predicted by such processes. Adding a resonance amplitude for the resonance at $m$=~2.37 GeV with $Gamma$ =~70 MeV and $I(J^P)=~0(3^+)$ observed recently in $pn o dpi^0pi^0$ and $pn o dpi^+pi^-$ reactions leads to an agreement with the data also at low energies.
Investigation of the dd -> 3henpi0 reaction with the FZ Jülich WASA-at-COSY facility
P. Adlarson, ..., W. Bardan, I. Ciepał, E. Czerwiński, M. Hodana, J. Klaja, W. Krzemień, I. Ozerianska, P. Moskal, M. Skurzok,M. Zieliński, et al.
abstract
An exclusive measurement of the dd?3Hen?0 reaction was carried out at a beam momentum of pd= 1.2 GeV/c using the WASA-at-COSY facility. Information on the total cross section as well as differential distributions was obtained. The data are described by a phenomenological approach based on a combination of a quasifree model and a partial wave expansion for the three-body reaction. The total cross section is found to be ?tot=(2.89?0.01stat?0.06sys?0.29norm) ?b. The contribution of the quasifree processes (with the beam or target neutron being a spectator) accounts for 38% of the total cross section and dominates the differential distributions in specific regions of phase space. The remaining part of the cross section can be described by a partial wave decomposition indicating the significance of p-wave contributions in the final state.
Search for a dark photon in the pi0->e+e-gamma decay
P. Adlarson, ..., M. Hodana, W. Krzemień, P. Moskal, I. Ozerianska, M. Skurzok, M. Zieliński et al.
abstract
The presently world largest data sample of pi0 --> gamma e+e- decays containing nearly 5E5 events was collected using the WASA detector at COSY. A search for a dark photon U produced in the pi0 --> gamma U --> gamma e+e- decay from the pp-->pppi^0 reaction was carried out. An upper limit on the square of the U-gamma mixing strength parameter epsilon^2 of 5e-6 at 90% CL was obtained for the mass range 30 MeV
TOF-PET detector concept based on organic scintillators
P. Moskal, T. Bednarski, P. Białas, M. Ciszewska, E. Czerwiński, A. Heczko, M. Kajetanowicz, Ł. Kapłon, A. Kochanowski, G. Konopka-Cupiał, G. Korcyl, W. Krzemień, K. Łojek, J. Majewski, W. Migdał, M. Molenda, S. Niedźwiecki, M. Pałka, Z. Rudy, P. Salabura, M. Silarski, A. Słomski, J. Smyrski, J. Zdebik, M. Zieliński
abstract
In this contribution we present a new concept of the large acceptance detector systems based on organic scintillators which may allow for simultaneous diagnostic of large fraction of the human body. Novelty of the concept lies in employing large blocks of polymer scintillators instead of crystals as detectors of annihilation quanta, and in using predominantly the timing of signals instead of their amplitudes.
Strip-PET: a novel detector concept for the TOF-PET scanner
P. Moskal, T. Bednarski, P. Białas, M. Ciszewska, E. Czerwiński, A. Heczko, M. Kajetanowicz, Ł. Kapłon, A. Kochanowski, G. Konopka-Cupiał, G. Korcyl, W. Krzemień, K. Łojek, J. Majewski, W. Migdał, M. Molenda, S. Niedźwiecki, M. Pałka, Z. Rudy, P. Salabura, M. Silarski, A. Słomski, J. Smyrski, J. Zdebik, M. Zieliński
abstract
We briefly present a design of a new PET scanner based on
strips of polymer scintillators arranged in a barrel constituting
a large acceptance detector. The solution proposed is based on
the superior timing properties of the polymer scintillators. The
position and time of the reaction of the gamma quanta in the
detector material will be determined based on the time of arrival
of light signals to the edges of the scintillator strips.
Trapped Antihydrogen in Its Ground State
G. Gabrielse, R. Kalra, W. S. Kolthammer, R. McConnell, P. Richerme, D. Grzonka, W. Oelert, T. Sefzick, M. Zieliński, D. W. Fitzakerley, M. C. George, E. A. Hessels, C. H. Storry, M. Weel, A. Müllers, J. Walz
abstract
Antihydrogen atoms are confined in an Ioffe trap for 15 to 1000 seconds -- long enough to ensure that they reach their ground state. Though reproducibility challenges remain in making large numbers of cold antiprotons and positrons interact, 5 +/- 1 simultaneously-confined ground state atoms are produced and observed on average, substantially more than previously reported. Increases in the number of simultaneously trapped antithydrogen atoms are critical if laser-cooling of trapped antihydrogen is to be demonstrated, and spectroscopic studies at interesting levels of precision are to be carried out.
Novel detector systems for the Positron Emission Tomography
P. Moskal, P. Salabura, M. Silarski, J. Smyrski, J. Zdebik, M. Zieliński
abstract
In this contribution we describe a novel solution for the construction of Positron Emission Tomograph. We present
the device allowing for determination of the impact position as well as time and depth of interaction of the annihilation gamma
quanta. The device is comprised of scintillation chamber consisting of organic scintillators surrounding the body of the patient.
We discuss two possible solutions: (i) the tomograph built out of scintillator strips, and (ii) the tomograph built out of the scintillator
plates. The application of the fast scintillators will enable to take advantage of the difference between time of the registration of
the annihilation quanta. The invented method will permit to use a thick layers of detector material with the possibility of measuring
the depth of the gamma quantum interaction (DOI) and the determination of their time of fl ight (TOF), and will allow for increasing
the size of the diagnostic chamber without a signifi cant increase of costs. The method is a subject of two patent applications
[1, 2] which are based on the techniques used in the particle physics experiments [3, 4].
Reaction pp->pp pi pi pi as a background for hadronic decay of the eta-prime meson
M. Zieliński, P. Moskal, A. Kupść
abstract
Isospin violating hadronic decays of the eta and eta' mesons into 3pi mesons are driven by a term in the QCD Lagrangian proportional to the mass difference of the d and u quarks. The source giving large yield of the mesons for such decay studies are pp interactions close to the respective kinematical thresholds. The most important physics background for eta,eta' opipipi is coming from direct three pion production reactions. In case of the eta meson the background for the decays is relatively low (approx 10%). The purpose of this article is to provide an estimate of the direct pion production background for the eta' o 3pi decays. Using the inclusive data from COSY-11 experiment we have extracted differential cross section for the pp->pp-multipion production reactions with the invariant mass of the pions equal to the eta' meson mass and estimated an upper limit for the signal to background ratio for studies of the eta' opi^+pi^-pi^0 decay.
Pumped helium system for cooling positron and electron traps to 1.2K
J. Wrubel, G. Gabrielse, W. S. Kolthammer, P. Larochelle, R. McConell, P. Richerme, D. Grzonka, W. Oelert, T. Sefzick, M. Zieliński, J. S. Borbely, M. C. George, E. A. Hassels, C. H. Storry, M. Weel, A. Muellers, J. Walz, A. Speck
abstract
Extremely precise tests of fundamental particle symmetries should be possible via laser spectroscopy of trapped antihydrogen () atoms. atoms that can be trapped must have an energy in temperature units that is below 0.5 K?the energy depth of the deepest magnetic traps that can currently be constructed with high currents and superconducting technology. The number of atoms in a Boltzmann distribution with energies lower than this trap depth depends sharply upon the temperature of the thermal distribution. For example, ten times more atoms with energies low enough to be trapped are in a thermal distribution at a temperature of 1.2 K than for a temperature of 4.2 K. To date, atoms have only been produced within traps whose electrode temperature is 4.2 K or higher. A lower temperature apparatus is desirable if usable numbers of atoms that can be trapped are to eventually be produced. This report is about the pumped helium apparatus that cooled the trap electrodes of an apparatus to 1.2 K for the first time. Significant apparatus challenges include the need to cool a 0.8 m stack of 37 trap electrodes separated by only a mm from the substantial mass of a 4.2 K Ioffe trap and the substantial mass of a 4.2 K solenoid. Access to the interior of the cold electrodes must be maintained for antiprotons, positrons, electrons and lasers.
Adiabatic Cooling of Antiprotons
G. Gabrielse, W. S. Kolthammer, R. McConell, P. Richerme, R. Kalra, E. Novitski, D. Grzonka, W. Oelert, T. Sefzick,M. Zieliński, D. Fitzakerley, M. C. George, E. A. Hassels, C. H. Storry, M. Weel, A. Müllers, J. Walz
abstract
Adiabatic cooling is shown to be a simple and effective method to cool many charged particles in a trap to very low temperatures. Up to 3×106 antiprotons are cooled to 3.5 K - 10^3 times more cold antiprotons and a 3 times lower antiproton temperature than previously reported. A second cooling method cools antiproton plasmas via the synchrotron radiation of embedded e- (with many fewer e- than antiproton ) in preparation for adiabatic cooling. No antiprotons are lost during either process - a significant advantage for rare particles.
Measurement of the eta->pi+pi-pi0 decay with WASA-at-COSY detector
P. Adlarson, M. Zieliński
abstract
One of the objectives of the physics programme of the WASA-at-COSY facility is to study the isospin violating eta hadronic decays into pi+pi-pi0 systems driven by the term of QCD Lagrangian which depends on the d and u quark mass difference. These studies can be made in terms of the Dalitz plot parameters describing the density population which is proportional to the square of the amplitude |A(x, y)|2. This contribution describes the current status of the analysis of the eta->pi+pi-pi0 decay in the pd->3He-eta and as well in the pp->pp-eta reaction with WASA-at-COSY.
Centrifugal separation of antiprotons and electrons
G. Gabrielse, W. S. Kolthammer, R. McConell, P. Richerme, J. Wrubel, R. Kalra, E. Novitski, D. Grzonka, W. Oelert, T. Sefzick, M. Zieliński, J. S. Borbely, D. Fitzakerley, M. C. George, E. A. Hassels, C. H. Storry, M. Weel, A. Müllers, J. Walz, A. Speck
abstract
Centrifugal separation of antiprotons and electrons is observed, the first such demonstration with particles that cannot be laser cooled or optically imaged. The spatial separation takes place during the electron cooling of trapped antiprotons, the only method available to produce cryogenic antiprotons for precision tests of fundamental symmetries and for cold antihydrogen studies. The centrifugal separation suggests a new approach for isolating low energy antiprotons and for producing a controlled mixture of antiprotons and electrons.
Determination of the total width of the eta-prime meson
E. Czerwiński, P. Moskal, D. Grzonka, R. Czyżykiewicz, D. Gil, B. Kamys, A. Khoukaz, J. Klaja, P. Klaja, W. Krzemień, W. Oelert, J. Ritman, T. Sefzick, M. Siemaszko, M. Silarski, J. Smyrski, A. Täschner, M. Wolke, P. Wüstner, J. Zdebik, M. Zieliński, W. Zipper
abstract
Taking advantage of both the low-emittance proton beam of the cooler synchrotron COSY and the high momentum precision of the COSY-11 detector system, the mass distribution of the eta-prime meson was measured with a resolution of 0.33??MeV/c2 (FWHM), improving the experimental mass resolution by almost an order of magnitude with respect to previous results. Based on the sample of more than 2300 reconstructed pp->pp eta-prime events, the total width of the eta-prime meson was determined to be Gamma(eta-prime) = 0.226+-0.017(stat)+-0.014(syst)??MeV/c2.
Two-proton correlation function for the pp -> pp + eta and pp to pp + pions reactions
P. Klaja, P. Moskal, E. Czerwiński, R. Czyżykiewicz, A. Deloff, D. Gil, D. Grzonka, B. Kamys, A. Khoukaz, J. Klaja, W. Krzemień, W. Oelert, J. Ritman, T. Sefzick, M. Siemaszko, M. Silarski, J. Smyrski, A. Täschner, M. Wolke, J. Zdebik, M. Zieliński, W. Zipper
abstract
For the very first time, the correlation femtoscopy method is applied to a kinematically complete measurement of meson production in the collisions of hadrons. A two-proton correlation function was derived from the data for the pp -> ppX reaction, measured near the threshold of eta meson production. A technique developed for the purpose of this analysis permitted the correlation function to be established separately for the production of the pp + eta and of the pp + pions systems. The shape of the two-proton correlation function for pp-eta differs from that for pp(pions) and both do not show a peak structure, opposite to the results determined for inclusive measurements of heavy ion collisions.
Two-proton correlation function for the pp -> pp plus eta and pp -> pp plus pions reactions
P. Klaja, P. Moskal, E. Czerwinski, R. Czyzykiewicz, A. Deloff, D. Gil, D. Grzonka, B. Kamys, A. Khoukaz, J. Klaja, W. Krzemien, W. Oelert, J. Ritman, T. Sefzick, M. Siemaszko, M. Silarski, J. Smyrski, A. Taschner, M. Wolke, J. Zdebik, M. Zielinski, W. Zipper
abstract
For the very first time, the correlation femtoscopy method is applied to a kinematically complete measurement of meson production in the collisions of hadrons. A two-proton correlation function was derived from the data for the pp -> ppX reaction, measured near the threshold of eta meson production. A technique developed for the purpose of this analysis permitted the correlation function to be established separately for the production of the pp + eta and of the pp + pions systems. The shape of the two-proton correlation function for pp eta differs from that for pp(pions) and both do not show a peak structure, opposite to the results determined for inclusive measurements of heavy ion collisions.
Upper limit of the total cross section for the pn->pn eta-prime reaction
J. Klaja, P. Moskal, S. D. Bass, E. Czerwiński, R. Czyżykiewicz, D. Gil, D. Grzonka, T. Johansson, B. Kamys, A. Khoukaz, P. Klaja, W. Krzemień, W. Oelert, B. Rejdych, J. Ritman, T. Sefzick, M. Siemaszko, M. Silarski, J. Smyrski, A. Täschner, M. Wolke, P. Wüstner, J. Zdebik, M. Zieliński, W. Zipper
abstract
The upper limit of the total cross section for the pn->pneta-prime reaction has been determined near the kinematical threshold in the excess energy range from 0 to 24 MeV. The measurement was performed using the COSY-11 detector setup, a deuteron cluster target, and the proton beam of COSY with a momentum of 3.35 GeV/c. The energy dependence of the upper limit of the cross section was extracted exploiting the Fermi momenta of nucleons inside the deuteron. Comparison of the determined upper limit of the ratio R(eta-prime)=sigma(pn->pneta-prime)/sigma(pp->ppeta-prime) with the corresponding ratio for eta-meson production does not favor the dominance of the N*(1535) resonance in the production process of the eta-prime meson and suggests nonidentical production mechanisms for eta and eta-prime mesons.
Measurement of the invariant mass distributions fot he pp->pp eta-prime reaction at excess energy of Q = 16.4 MeV
P. Klaja, P. Moskal, E. Czerwiński, R. Czyżykiewicz, A. Deloff, D. Gil, D. Grzonka, L. Jarczyk, B. Kamys, A. Khoukaz, J. Klaja, K. Nakayama, W. Oelert, J. Ritman, T. Sefzick, M. Siemaszko, M. Silarski, J. Smyrski, A. Täschner, M. Wolke, J. Zdebik, M. Zieliński, W. Zipper
abstract
The proton?proton and proton? invariant mass distributions have been determined for the reaction at an excess energy of . The measurement was carried out using the COSY-11 detector setup and the proton beam of the cooler synchrotron COSY. The shapes of the determined invariant mass distributions are similar to those of the reaction and reveal an enhancement for large relative proton?proton momenta. This result, together with the fact that the proton?? interaction is much stronger that the proton? interaction, excludes the hypothesis that the observed enhancement is caused by the interaction between the proton and the meson.
Upper limit of the total cross section for the pn -> pn eta' reaction
J. Klaja, P. Moskal, SD. Bass, E. Czerwinski, R. Czyzykiewicz, D. Gil, D. Grzonka, T. Johansson, B. Kamys, A. Khoukaz, P. Klaja, W. Krzemien, W. Oelert, B. Rejdych, J. Ritman, T. Sefzick, M. Siemaszko, M. Silarski, J. Smyrski, A. Taschner, M. Wolke, P. Wustner, J. Zdebik, M. Zielinski, W. Zipper
abstract
The upper limit of the total cross section for the pn -> pn eta' reaction has been determined near the kinematical threshold in the excess energy range from 0 to 24 MeV. The measurement was performed using the COSY-11 detector setup, a deuteron cluster target, and the proton beam of COSY with a momentum of 3.35 GeV/c. The energy dependence of the upper limit of the cross section was extracted exploiting the Fermi momenta of nucleons inside the deuteron. Comparison of the determined upper limit of the ratio R-eta' = sigma(pn -> pn eta')/sigma(pp -> pp eta') with the corresponding ratio for eta-meson production does not favor the dominance of the N*(1535) resonance in the production process of the eta' meson and suggests nonidentical production mechanisms for eta and eta' mesons.
Measurement of the invariant mass distributions for the pp -> pp eta ' reaction at excess energy of Q=16.4 MeV
P. Klaja, P. Moskal, E. Czerwinski, R. Czyzykiewicz, A. Deloff, D. Gil, D. Grzonka, L. Jarczyk, B. Kamys, A. Khoukaz, J. Klaja, K. Nakayama, W. Oelert, J. Ritman, T. Sefzick, M. Siemaszko, M. Silarski, J. Smyrski, A. Taschner, M. Wolke, J. Zdebik, M. Zielinski, W. Zipper
abstract
The proton-proton and proton-eta' invariant mass distributions have been determined for the pp -> pp eta' reaction at an excess energy of Q = 16.4 MeV. The measurement was carried Out using the COSY-11 detector setup and the proton beam of the cooler synchrotron COSY. The shapes of the determined invariant mass distributions are similar to those of the pp -> pp eta reaction and reveal an enhancement for large relative proton-proton momenta. This result, together with the fact that the proton-eta interaction is Much stronger that the proton-eta' interaction, excludes the hypothesis that the observed enhancement is caused by the interaction between the proton and the meson. (C) 2010 Elsevier B.V. All rights reserved.
Invariant mass distributions for the pp->pp eta reaction at Q = 10 MeV
P. Moskal, R. Czyżykiewicz, E. Czerwiński, D. Gil, D. Grzonka, L. Jarczyk, B. Kamys, A. Khoukaz, J. Klaja, P. Klaja, W. Krzemień, W. Oelert, J. Ritman, T. Sefzick, M. Siemaszko, M. Silarski, J. Smyrski, A. Taschner, M. Wolke, P. Wustner, J. Zdebik, M. Zieliński, W. Zipper
abstract
Proton-proton and proton-eta invariant-mass distributions and the total cross-section for the pp -> pp h reaction have been determined near the threshold at an excess energy of Q = 10 MeV. The experiment has been conducted using the COSY-11 detector setup and the cooler synchrotron COSY. The determined invariant-mass spectra reveal significant enhancements in the region of low proton-proton relative momenta, similarly as observed previously at higher excess energies of Q = 15.5 MeV and Q = 40 MeV.
Generalized Dalitz plot analysis of the near-threshold pp -> ppK(+)K(-) reaction in view of the K+K- final state interaction
M. Silarski, P. Moskal, E. Czerwinski, R. Czyzykiewicz, D. Gil, D. Grzonka, L. Jarczyk, B. Kamys, A. Khoukaz, J. Klaja, P. Klaja, W. Krzemien, W. Oelert, J. Ritman, T. Sefzick, M. Siemaszko, J. Smyrski, A. Taschner, P. Winter, M. Wolke, P. Wustner, M. Zielinski, W. Zipper, J. Zdebik
abstract
The excitation function for the pp -> ppK(+)K(-) reaction revealed a significant enhancement close to threshold that may plausibly be assigned to the influence of the pK(-) and K+K- final-state interactions. In an improved reanalysis of COSY-11 data for the pp -> ppK(+)K(-) reaction at excess energies of Q = 10 and 28 MeV, including the proton-K- interaction, the enhancement is confirmed. Invariant mass distributions for the two- and three-particle subsystems allow us to test at low excess energies the ansatz and parameters for the description of the interaction in the ppK(+)K(-) system as derived from the COSY-ANKE data. Finally, based for the first time on the low-energy K+K- invariant mass distributions and the generalized Dalitz plot analysis, we estimate the scattering length for the K+K- interaction to be vertical bar Re(a(K+K-))vertical bar = 0.5(-0.5)(+4.0) fm and Im(a(K+K-)) = 3.0 +/- 3.0 fm.
Generalized Dalitz plot analysis of the near-threshold pp->ppK+K- reaction in view of the K+K- final state interaction
M. Silarski, P. Moskal, E. Czerwiński, R. Czyżykiewicz, D. Gil, D. Grzonka, L. Jarczyk, B. Kamys, A. Khoukaz, J. Klaja, P. Klaja, W. Krzemień, W. Oelert, J. Ritman, T. Sefzick, M. Siemaszko, J. Smyrski, A. Täschner, P. Winter, M. Wolke, P. Wüstner, M. Zieliński, W. Zipper, J. Zdebik
abstract
The excitation function for the pp->ppK+K- reaction revealed a significant enhancement close to threshold which may plausibly be assigned to the influence of the pK- and K+K- final state interactions. In an improved reanalysis of COSY-11 data for the pp-> ppK+K- reaction at excess energies of Q = 10 MeV and 28 MeV including the proton-K- interaction the enhancement is confirmed. Invariant mass distributions for the two- and three-particle subsystems allow to test at low excess energies the ansatz and parameters for the description of the interaction in the ppK+K- system as derived from the COSY-ANKE data. Finally, based for the first time on the low energy K+K- invariant mass distributions and the generalized Dalitz plot analysis, we estimate the scattering length for the K+K- interaction to be |Re(a_K+K-)| = 0.5 + 4.0 -0.5 fm and Im(a_K+K-) = 3.0 +- 3.0 fm.
Measurement of the eta->3pi0 Dalitz plot distribution with the WASA detector at COSY
WASA-at-COSY Collaboration: C. Adolph, ..., E. Czerwiński, R. Czyżykiewicz, M. Hodana, M. Janusz, J. Klaja, P. Klaja, W. Krzemień, P. Moskal, M. Zieliński, et al.
abstract
In the first production run of the WASA experiment at COSY, the eta decay into three neutral pions was measured in proton?proton interactions at a proton beam kinetic energy of 1.4 GeV. The Dalitz plot of the three pions was studied using fully reconstructed events, and the quadratic slope parameter ? was determined to be . The result is consistent with previous measurements and further corroborates the importance of pion?pion final state interactions.
Near-threshold production of the eta meson via the quasi-free pn->pneta reaction
P. Moskal, R. Czyżykiewicz, H.-H. Adam, S. D. Bass, A. Budzanowski, E. Czerwiński, D. Gil, D. Grzonka, M. Janusz, L. Jarczyk, T. Johansson, B. Kamys, A. Khoukaz, K. Kilian, P. Klaja, J. Majewski, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, B. Rejdych, J. Ritman, T. Rozek, T. Sefzick, M. Siemaszko, M. Silarski, J. Smyrski, A. Taeschner, M. Wolke, P. Wuestner, M. Zieliński, W. Zipper, J. Zdebik
abstract
Total cross sections for the quasifree pn->pn? reaction in the range from the kinematical threshold up to 20 MeV excess energy have been determined. At threshold they exceed corresponding cross sections for the pp?pp? reaction by a factor of about 3 in contrast to the factor of 6 established for higher excess energies. To large extent, the observed decrease of the ratio sigma(pn->pn?)/sigma(pp->pp?) toward threshold may be assigned to the different energy dependence of the proton-proton and proton-neutron final-state interactions. The experiment was conducted using a proton beam of the cooler synchrotron COSY and a cluster jet deuteron target. The proton-neutron reactions were tagged by the spectator proton whose momentum was measured for each event. Protons and neutron outgoing from the pn?pn? reaction have been registered by means of the COSY-11 facility, an apparatus dedicated for threshold meson production.
Isospin dependence of the eta-prime meson production in nucleon-nucleon collisions
J. Przerwa, P. Moskal, A. Budzanowski, E. Czerwiński, R. Czyżykiewicz, D. Gil, D. Grzonka, L. Jarczyk, T. Johansson, B. Kamys, A. Khoukaz, P. Klaja, W. Krzemień, W. Oelert, C. Piskor-Ignatowicz, J. Ritman, B. Rejdych, T. Sefzick, M. Siemaszko, M. Silarski, J. Smyrski, A. Taschner, M. Wolke, P. Wustner, J. Zdebik, M. Zieliński, W. Zipper
abstract
A comparison of the close-to-threshold total cross section for the eta prime production in pp -> pp eta prime and pn -> pn eta prime reactions constitutes a tool to investigate the eta prime meson structure and the reaction mechanism in the channels of isospin I=0 and I=1 and may provide insight into the flavour-singlet (perhaps also into gluonium) content of the eta prime meson. In this contribution we present preliminary results of measurement of the quasi-free production of the eta prime meson in the proton-neutron collisions conducted using the COSY-11 facility.
Search for the 3He-eta bound state at COSY-11
W. Krzemien, J. Smyrski, A. Budzanowski, E. Czerwiński, R. Czyżykiewicz, D. Gil, D. Grzonka, L. Jarczyk, B. Kamys, A. Khoukaz, P. Klaja, P. Moskal, W. Oelert, J. Przerwa, J. Ritman, T. Sefzick, M. Siemaszko, M. Silarski, A. Taeschner, M. Wolke, P. Wuestner, J. Zdebik, M. Zieliński, W. Zipper
abstract
We have measured excitation function for dp -> ppp_pi- reaction near the eta production threshold. We observe an enhancement of the counting rate above the threshold which can originate from the production of the eta meson in the reaction dp -> 3He eta and its subsequent absorption on neutron in the 3He nucleus leading to creation of the p_pi- pair.
Near-threshold production of the eta meson via the quasifree pn -> pn eta reaction
P. Moskal, R. Czyzykiewicz, HH. Adam, SD. Bass, A. Budzanowski, E. Czerwinski, D. Gil, D. Grzonka, M. Janusz, L. Jarczyk, T. Johansson, B. Kamys, A. Khoukaz, K. Kilian, P. Klaja, J. Majewski, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, B. Rejdych, J. Ritman, T. Rozek, T. Sefzick, M. Siemaszko, M. Silarski, J. Smyrski, A. Taschner, M. Wolke, P. Wustner, M. Zielinski, W. Zipper, J. Zdebik
abstract
Total cross sections for the quasifree pn -> pn eta reaction in the range from the kinematical threshold up to 20 MeV excess energy have been determined. At threshold they exceed corresponding cross sections for the pn -> pn eta reaction by a factor of about 3 in contrast to the factor of 6 established for higher excess energies. To large extent, the observed decrease of the ratio s(pn -> pn eta)/s=sigma(pn -> pn eta) toward threshold may be assigned to the different energy dependence of the proton-proton and proton-neutron final-state interactions. The experiment was conducted using a proton beam of the cooler synchrotron COSY and a cluster jet deuteron target. The proton- neutron reactions were tagged by the spectator proton whose momentum was measured for each event. Protons and neutron outgoing from the pn -> pn eta reaction have been registered by means of the COSY-11 facility, an apparatus dedicated for threshold meson production.
Near threshold production of the pseudoscalar mesons at the COSY-11 facility
P. Moskal, R. Czyzykiewicz, HH. Adam, A. Budzanowski, E. Czerwinski, D. Gil, D. Grzonka, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, X. Kilian, P. Klaja, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, B. Rejdych, J. Ritman, T. Sefzick, M. Siemaszko, M. Silarski, J. Smyrski, A. Taschner, M. Wolke, P. Winter, P. Wustner, M. Zielinski, W. Zipper
abstract
We summarise measurements of the COSY-11 collaboration concerning the excitation functions of the near threshold pseudoscalar meson production in the proton-proton interaction. The results are discussed in the context of the meson-nucleon and hyperon-nucleon interactions. We conclude that the eta-proton interaction is significantly stronger than the eta'-proton interaction. Similarly, we found that the hyperon Lambda interacts with the nucleon considerably stronger than the hyperon Sigma, and that the interaction of K--proton is much stronger than this of the K+-proton.
Dynamics of the near threshold eta meson production in proton-proton interaction
R. Czyzykiewicz, P. MoSkal, HH. Adam, A. Budzanowski, E. Czerwinski, D. Gil, D. Grzonka, M. Hodana, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, K. Kilian, P. Klaja, B. Lorentz, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, B. Rejdych, J. Ritman, T. Sefzick, M. Siemaszko, M. Silarski, J. Smyrski, A. Taschner, K. Ulbrich, P. Winter, M. Wolke, P. Wustner, M. Zielinski, W. Zipper
abstract
We present the results of measurements of the analysing power for the pp -> pp eta reaction at the excess energies of Q = 10 and 36 MeV, and interpret these results within the framework of the meson exchange models. The determined values of the analysing power at both excess energies are consistent with zero implying that the eta meson is produced predominantly in s-wave.
Study of the low energy interaction of hadrons at COSY-11
P. Moskal, R. Czyżykiewicz, E. Czerwiński, D. Grzonka, A. Budzanowski, D. Gil, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, P. Klaja, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, B. Rejdych, J. Ritman, T. Sefzick, M. Siemaszko, M. Silarski, J. Smyrski, A. Täschner, M. Wolke, P. Wüstner, M. Zieliński, W. Zipper
abstract
We summarize the studies of the low energy hadronic interaction of the KK and pK system performed by the COSY-11 collaboration. We discuss also the question of the existence of the ??3He bound state in the context of the experiments conducted by means of the COSY-11 facility
Direct measurement of the total width of the eta prime meson
E. Czerwiński, P. Moskal, D. Grzonka, A. Budzanowski, R. Czyżykiewiczy, D. Gil, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, P. Klaja, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, B. Rejdych, J. Ritman, T. Sefzick, M. Siemaszko, M. Silarski, J. Smyrski, A. Täschner, M. Wolke, P. Wüstner, M. Zieliński, W. Zipper
abstract
Using stochastically cooled proton beam of the cooler synchrotron COSY and the COSY-11 apparatus we have measured the mass distribution of the eta prime meson producing it via the pp->ppeta' reaction. The preliminary analysis shows that the achieved experimental mass resolution amounts to about 0.3 MeV (FWHM). Such precision with about 2300 events gathered at five excess energies should permit for the extraction of the width of the eta' meson with an accuracy of about 10 keV. In this article we describe the method of the mea-surement and present preliminary results.
Study of Three-Nucleon Dynamics in the dp breakup collisions using the WASA detector
P. Adlarson, ..., E. Czerwiński, O. Khreptak, W. Krzemień, P. Moskal, O. Rundel, I. Schätti-Ozerianska, M. Skurzok, M.J. Zieliński, et al.
published in: Springer Proc. Phys. 238 (2020) 455
Differential cross section for the 1H(d,pp)n breakup reaction at deuteron beam energy of 340 MeV has been measured with the use of WASA detector at COSY-Juelich. The set of proton-proton coincidences registered at Forward Detector has been analysed on dense grid of kinematic variables, giving in total around 5600 data points. The cross section data are compared to theoretical predictions based on the state-of-the-art nucleon-nucleon potentials, combined with three-nucleon force, Coulomb interaction or carried out in a relativistic regime.
Drift chamber calibration and particle identification in the P-349 experiment
D. Alfs, A. Asaturyan, M. Carmignotto, M. Diermaier, W. Eyrich, B. Głowacz, D. Grzonka, F. Hauenstein, T. Horn, K. Kilian, D. Lersch, S. Malbrunot-Ettenauer, A. Mkrtchyan, H. Mkrtchyan, P. Moskal, P. Nadel-Turonski, W. Oelert, J. Ritman, T. Sefzick, V. Tadevosyan, E. Widmann, M. Wolke, S. Zhamkochyan, M. Zieliński, A. Zink and J. Zmeskal
published in: EPJ Web Conf. 199 (2019) 05017
The goal of the P-349 experiment is to test whether 3.5 GeV/c antiprotons produced in high-energy proton-proton collisions are polarized in view of the preparation of a polarized antiproton beam. In this article, we present the details of the ongoing analysis focused on the drift chambers calibration and particle identification with DIRC.
Polarization analysis of antiprotons produced in pA collisions
D. Alfs, A. Asaturyan, M. Carmignotto, M. Diermaier, W. Eyrich, B. Głowacz, D. Grzonka, F. Hauenstein, T. Horn, K. Kilian, D. Lersch, S. Malbrunot-Ettenauer, A. Mkrtchyan, H. Mkrtchyan, P. Moskal, P. Nadel-Turonski, W. Oelert, J. Ritman, T. Sefzick, V. Tadevosyan, E. Widmann, M. Wolke, S. Zhamkochyan, M. Zieliński, A. Zink and J. Zmeskal
published in: EPJ Web Conf. 199 (2019) 05013
A quite simple procedure for the generation of a polarized antiproton beam could be worked out if antiprotons are produced with some polarization. In order to investigate this possibility measurements of the polarization of produced antiprotons have been started at a CERN/PS test beam. The polarization will be determined from the asymmetry of the elastic antiproton scattering at a liquid hydrogen target in the CNI region for which the analyzing power is well known. The data are under analysis and an additional measurement is done in 2018. Details on the experiment and the ongoing data analysis will be given.
Studies of discrete symmetries in decays of positronium atoms
E. Czerwiński, C. Curceanu, K. Dulski, A. Gajos, M. Gorgol, A. Heczko, B. C. Hiesmayr, B. Jasińska, D. Kisielewska, G. Korcyl, B. Korzeniak, P. Kowalski, T. Kozik, W. Krzemień, E. Kubicz, W. Migdał, M. Mohammed, S. Niedźwiecki, M. Pałka, M. Pawlik-Niedźwiecka, L. Raczyński, J. Raj, Z. Rudy, S. Sharma, S. Shivani, R. Y. Shopa, M. Silarski, M. Skurzok, W. Wiślicki, B. Zgardzińska, M. Zieliński and P. Moskal
published in: EPJ Web Conf. 181 (2018) 01019
A positronium - a bound state of electron and positron - is an eigenstate of parity and charge conjugation operators which decays into photons. It is a unique laboratory to study discrete symmetries whose precision is limited, in principle, by the effects due to the weak interactions expected at the level of 10?14 and photon-photon interactions expected at the level of 10-9.
The Jagiellonian Positron Emission Tomograph (J-PET) is a detector for medical imaging as well as for physics studies involving detection of electronpositron annihilation into photons. The physics case covers the areas of discrete symmetries studies and genuine multipartite entanglement. The J-PET detector has high angular and time resolution and allows for determination of spin of the positronium and the momenta and polarization vectors of annihilation quanta. In this article, we present the potential of the J-PET system for studies of discrete symmetries in decays of positronium atoms.
J-PET: A novel TOF-PET detector based on plastic scintillators
Paweł Moskal, Dominika Alfs, Tomasz Bednarski, Piotr Białas, Catalina Curceanu, Eryk Czerwiński, Kamil Dulski, Aleksander Gajos, Bartosz Głowacz, Marek Gorgol, Beatrix Hiesmayr, Bożena Jasińska, Daria Kamińska, Grzegorz Korcyl, Paweł Kowalski, Tomasz Kozik, Wojciech Krzemień, Ewelina Kubicz, Muhsin Mohammed, Monika Pawlik-Niedźwiecka, Szymon Niedźwiecki, Marek Pałka, Lech Raczyźski, Zbigniew Rudy, Oleksandr Rundel, Neha Gupta Sharma, Michał Silarski, Jerzy Smyrski, Adam Strzelecki, Anna Wieczorek, Wojciech Wiślicki, Bożena Zgardzińska, Marcin Zieliński
published in: IEEE Xplore: Nucl. Sci. Symp., Med. Imag. Conf. and Room-Temp. Semiconductor Detector Workshop, DOI:10.1109/NSSMIC.2016.8069617
Statistical Analysis of Time Resolution of the J-PET Scanner
L. Raczyński, W. Wiślicki, P. Kowalski, W. Krzemień, D. Alfs, T. Bednarski, P. Białas, C. Curceanu, E. Czerwiński, K. Dulski, A. Gajos, B. Głowacz, M. Gorgol, B. Hiesmayr, B. Jasińska, D. Kamińska, G. Korcyl, T. Kozik, N. Krawczyk, E. Kubicz, M. Mohammed, M. Pawlik-Niedźwiecka, S. Niedźwiecki, M. Pałka, Z. Rudy, O. Rundel, N. Gupta Sharma, M. Silarski, J. Smyrski, A. Strzelecki, A. Wieczorek, B. Zgardzińska, M. Zieliński, P. Moskal
published in: IEEE Xplore: Nucl. Sci. Symp., Med. Imag. Conf. and Room-Temp. Semiconductor Detector Workshop, DOI:10.1109/NSSMIC.2016.8069407
Determination of the analysing power for the vec{p} p ->pp eta reaction using WASA-at-COSY detector system
P. Adlarson, ...,E. Czerwiński, O. Khreptak, W. Krzemień, P. Moskal, O. Rundel, M. Skurzok, M. Zieliński et al. (WASA-at-COSY Collaboration)
published in: PoS BORMIO2016 (2016) 016
We report on the measurement of the analyzing power for the ~ pp -> pp eta reaction with beam
momenta of 2026 MeV/c and 2188 MeV/c performed with the WASA-at-COSY detector at the
Cooler Synchrotron COSY. The eta meson from the pp -> pp eta reaction was identified by the tech-
niques of missing mass and invariant mass. The angular distribution of the determined analyzing
power strongly disagrees with theoretical predictions. A comparison of the obtained A y angular
distribution with a series of associated Legendre polynomials revealed negligible contribution of
the Sd partial wave at Q = 15 MeV. However, at Q = 72 MeV, a significant interference of the Ps
and Pp partial waves was observed.
Studies of discrete symmetries in a purely leptonic system using the Jagiellonian Positron Emission Tomograph
P. Moskal, D. Alfs, T. Bednarski, P. Białas, C. Curceanu, E. Czerwiński, K. Dulski, A. Gajos, B. Głowacz, N. Gupta-Sharma, M. Gorgol, B. C. Hiesmayr, B. Jasińska, D. Kamińska, O. Khreptak, G. Korcyl, P. Kowalski, W. Krzemień, N. Krawczyk, E. Kubicz, M. Mohammed, Sz. Niedźwiecki, M. Pawlik-Niedźwiecka, L. Raczyński, Z. Rudy, M. Silarski, J. Smyrski, A. Wieczorek, W. Wiślicki, B. Zgardzińska, and M. Zieliński
published in: EPJ Web Conf. 130 (2016) 07015
Discrete symmetries such as parity (P), charge-conjugation (C) and time reversal (T) are of fundamental importance in physics and cosmology. Breaking of charge conjugation symmetry (C) and its combination with parity (CP) constitute necessary conditions for the existence of the asymmetry between matter and antimatter in the observed Universe. The presently known sources of discrete symmetries violations can account for only a tiny fraction of the excess of matter over antimatter. So far CP and T symmetries violations were observed only for systems involving quarks and they were never reported for the purely leptonic objects. In this article we describe briefly an experimental proposal for the test of discrete symmetries in the decays of positronium atom which is made exclusively of leptons. The experiments are conducted by means of the Jagiellonian Positron Emission Tomograph (J-PET) which is constructed from strips of plastic scintillators enabling registration of photons from the positronium annihilation. J-PET tomograph together with the positronium target system enable to measure expectation values for the discrete symmetries odd operators constructed from (i) spin vector of the ortho-positronium atom, (ii) momentum vectors of photons originating from the decay of positronium, and (iii) linear polarization direction of annihilation photons. Linearly polarized positronium will be produced in the highly porous aerogel or polymer targets, exploiting longitudinally polarized positrons emitted by the sodium 22Na isotope. Information about the polarization vector of orthopositronium will be available on the event by event basis and will be reconstructed from the known position of the positron source and the reconstructed position of the orthopositronium annihilation. In 2016 the first tests and calibration runs are planned, and the
data collection with high statistics will commence in the year 2017.
Status of the analysis for the search of polarization in the antiproton production process
D. Alfs, A. Asaturyan, M. Carmignotto, M. Diermaier, W. Eyrich, B. Głowacz, D. Grzonka, F. Hauenstein, T. Horn, K. Kilian, S. Malbrunot-Ettenauer, A. Mkrtchyan, H. Mkrtchyan, P. Moskal, P. Nadel-Turonski, W. Oelert, J. Ritman, T. Sefzick, V. Tadevosyan, E. Widmann, M. Wolke, S. Zhamkochyan, M. Zieliński, A. Zink, and J. Zmeskal
published in: EPJ Web Conf. 130 (2016) 07002
The P-349 experiment aims to test whether for antiprotons the production process itself can be a source of polarization in view of the preparation of a polarized antiproton beam. In this article we present the details of performed measurements and report on the status of the ongoing analysis.
J-PET detector system for studies of the electron-positron annihilations
M. Pawlik-Niedźwiecka, O. Khreptak, A. Gajos, A. Wieczorek, D. Alfs, T. Bednarski, P. Białas, C. Curceanu, E. Czerwiński, K. Dulski, B. Głowacz, N. Gupta-Sharma, M. Gorgol, B. C. Hiesmayr, B. Jasińska, D. Kamińska, G. Korcyl, P. Kowalski, W. Krzmień, N. Krawczyk, E. Kubicz, M. Mohammed, Sz. Niedźwiecki, L. Raczyński, Z. Rudy, M. Silarski, W. Wiślicki, B. Zgardzińska, M. Zieliński, and P. Moskal
published in: EPJ Web Conf. 130 (2016) 07020
Jagiellonian Positron Emission Tomograph (J-PET) has been recently constructed at the Jagiellonian University as a prototype of a cost-effective scanner for the metabolic imaging of the whole human body. J-PET detector is optimized for the measurement of momentum and polarization of photons from the electron-positron annihilations. It is built out of strips of plastic scintillators, forming three cylindrical layers. As detector of gamma quanta it will be used for studies of discrete symmetries and multiparticle entanglement of photons originating from the decays of ortho-positronium atoms.
Production and interaction of the eta meson with nucleons and nuclei
W. Krzemień, O. Khreptak, P. Moskal, I. Ozyrianska-Schaetti, O. Rundel, M. Skurzok and M. Zieliński
published in: EPJ Web Conf. 130 (2016) 03004
We report on the status of the search for eta-mesic nuclei and the studies of the interaction of the eta meson with nucleons. Recently we have completed the analysis of the new WASA-at-COSY data on the production of the eta meson with polarized proton beam. New results on the analyzing power for the p?p -> pp? reaction with more than an order of magnitude improved precision shed a new light on the production mechanism of the eta meson in nucleon-nucleon collisions. Also, the latest results of the search for eta-mesic nuclei are discussed.
A novel TOF-PET detector based on plastic scintillators
W. Krzemien, D. Alfs, T. Bednarski, P. Białas, E. Czerwiński, K. Dulski, A. Gajos, B. Głowacz, M. Gorgol, ´ B. Jasińska, D. Kamińska, Ł. Kapłon, G. Korcyl, P. Kowalski, T. Kozik, E. Kubicz, M. Mohammed, ´ Sz. Niedźwiecki, M. Pałka, M. Pawlik-Niedźwiecka, L. Raczyński, Z. Rudy, O. Rundel, N.G. Sharma, M. Silarski, A. Słomski, K. Stola, A. Strzelecki, A. Wieczorek, W. Wiślicki, B. K. Zgradzińska, M. Zieliński, P. Moskal
published in: Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC) (2015) IEEE
The Jagiellonian-PET (J-PET) collaboration is developing
a novel TOF-PET tomography scanner based mainly
on the timing of signals instead of their amplitudes for the
reconstruction of Lines-of-Response, therefore a very precise time
resolution is one of the main challenges of the project. The
novelty of the concept lies in employing long strips of plastic
scintillators instead of crystals as detectors of the annihilation
quanta. The diagnostic chamber consists of plastic scintillator
strips readout by pairs of photomultipliers arranged axially
around a cylindrical surface. To take advantage of the superior
timing properties of plastic scintillators, the signals are sampled
in the voltage domain with an accuracy of 20 ps by novel ultrafast
electronics, and the data are collected by the FPGA-based
trigger-less data acquisition system. The hit-position and hittime
are reconstructed by the dedicated reconstruction methods
based on the compressing sensing theory and a library of
synchronized model signals. The solutions are subject of sixteen
patent applications. So far, a time-of-flight resolution of 125 ps
(?) was achieved for a double-strip prototype with 30 cm fieldof-view
(FOV). It is by more than a factor of two better than the
TOF resolution achievable in current TOF-PET modalities and
at the same time, the FOV of 30 cm long prototype is significantly
larger with respect to typical commercial PET devices. The axial
geometry gives unique possibilities of combining J-PET with
Computed Tomography or with Magnetic Resonance Imaging,
allowing to perform the simultaneous scan of the patient with
both methods.
Polarization determination for the studies of the eta meson production
I. Ozerianska, P. Moskal, M. Zieliński
published in: EPJ Web Conf. 81 (2014) 02013
The dynamics of ? meson production and the interaction of ? mesons with nucleons can be studied using the ?p p?pp? reaction via measurements of the analyzing power Ay. To this end, we have performed a measurement of the ?p p ?pp? reaction using the large acceptance and ? symmetric WASA-at-COSY detector, for beam momenta of 2026 MeV/c and 2188 MeV/c.
System Response Kernel Calculation for List-mode Reconstruction in Strip PET Detector
P. Białas, J. Kowal, A. Strzelecki, T. Bednarski, E. Czerwiński, Ł. Kapłon, A. Kochanowski, G. Korcyl, P. Kowalski, T. Kozik, W. Krzemień, M. Molenda, P. Moskal, Sz. Niedźwiecki, M. Pałka, M. Pawlik, L. Raczyński, Z. Rudy, P. Salabura, N. Gupta-Sharma, M. Silarski, A. Słomski, J. Smyrski, W. Wiślicki, M. Zieliński
published in: Acta Phys. Polon. B Suppl. 6 (2013) 1027-1036
Reconstruction of the image in Positron Emission Tomographs (PET) requires the knowledge of the system response kernel which describes the contribution of each pixel (voxel) to each tube of response (TOR). This is especially important in list-mode reconstruction systems, where an efficient analytical approximation of such function is required. In this contribution, we present a derivation of the system response kernel for a novel 2D strip PET.
Studies on Antihydrogen Atoms with the ATRAP Experiment at CERN
M. Zieliński, et al.
published in: Acta Phys. Polon. B Suppl. 6 (2013) 1093-1099
The CPT theorem predicts the same properties of matter and antimatter, however, in the nearby Universe, we observe a huge imbalance of matter and antimatter. Therefore, it is intriguing to measure the properties of particles and antiparticles in order to contribute to an explanation of this phenomena. In this article, we will describe the experimental efforts of the ATRAP Collaboration in order to test the CPT theorem using antihydrogen atoms.
Application of Compressive Sensing Theory for the Reconstruction of Signals in Plastic Scintillators
L. Raczyński, P. Kowalski, T. Bednarski, P. Białas, E. Czerwiński, Ł. Kapłon, A. Kochanowski, G. Korcyl, J. Kowal, T. Kozik, W. Krzemień, M. Molenda, P. Moskal, Sz. Niedźwiecki, M. Pałka, M. Pawlik, Z. Rudy, P. Salabura, N.G. Sharma, M. Silarski, A. Słomski, J. Smyrski, A. Strzelecki, W. Wiślicki, M. Zieliński
published in: Acta Phys. Polon. B Suppl. 6 (2013) 1121-1127
Compressive Sensing theory says that it is possible to reconstruct a measured signal if an enough sparse representation of this signal exists in comparison to the number of random measurements. This theory was applied to reconstruct signals from measurements of plastic scintillators. Sparse representation of obtained signals was found using SVD transform.
Test of charge conjugation invariance in the decay of the eta meson into pi(+)pi(-)pi(0)
M. Zieliński, P. Moskal
published in: EPJ Web Conf. 37 (2012) 09037
In this work we present the preliminary results of the analysis of the pp->pp
eta(->pp pi(+)pi(-)pi(0) reaction aiming to test the charge conjugation
symmetry C in strong interactions. Based on approximately $10^5$ identified
eta->pi(+)pi(-)pi(0) decay events we have extracted asymmetry parameters
sensitive to C symmetry violation for different isospin values of the final
state and we have established that all are consistent with zero within the
obtained accuracy.
MATRIX-PET: A novel PET detector concept based on large blocks of organic scintillators
P. Moskal, T. Bednarski, A. Heczko, M. Kajetanowicz, Ł. Kapłon, A. Kochanowski, G. Konopka - Cupiał, G. Korcyl, W. Krzemień, K. Łojek, W. Migdał, M. Molenda, S. Niedzwiecki, P. Salabura. M. Silarski, A. Słomski, J. Smyrski, Z. Rudy, J. Zdebik, M. Zieliński
published in: Nuclear Medicine Review 15 (2012) A47-A48
Matrix-PET is a novel detector solution for the Positron Emission Tomography. It is one of the
two methods which is developed at present at the Jagiellonian University.
STRIP-PET: Concept of TOF-PET scanner based on polymer scintillator strips
P. Moskal, T. Bednarski, A. Heczko, M. Kajetanowicz, Ł. Kapłon, A. Kochanowski, G. Konopka - Cupiał, G. Korcyl, W. Krzemień, K. Łojek, W. Migdał, M. Molenda, S. Niedźwiecki, P. Salabura. M. Silarski, A. Słomski, J. Smyrski, Z. Rudy, J. Zdebik, M. Zieliński
published in: Nuclear Medicine Review 15 (2012) A61-A63
The aim of the poster is to present an idea of a new PET scanner based on strips of polymer scintillators
arranged in a large acceptance detector system which may allow a simultaneous diagnostic
of a large fraction of (or even the whole) human body.
Polymer Scintillator Detectors for TOF-PET with Large Longitudinal Field of View
P. Moskal, T. Bednarski, A. Heczko, M. Kajetanowicz, Ł. Kapłon, A. Kochanowski, G. Konopka - Cupiał, G. Korcyl, W. Krzemień, K. Łojek, W. Migdał, M. Molenda, S. Niedzwiecki, P. Salabura. M. Silarski, A. Słomski, J. Smyrski, Z. Rudy, J. Zdebik, M. Zieliński
published in: Nuclear Medicine Review 15 (2012) A25-A26
In this contribution we present a concept of the large acceptance detector systems based on
the organic scintillators which in the future may allow for simultaneous diagnostic of large fraction
of the human body.
Fortschritte bei ATRAP hin zu gespeichertem Antiwasserstoff
W. Oelert, D. Grzonka, T. Sefzick, M. Zieliński
published in: Verhandlungen der Deutschen Physikalischen Gesellschaft 2, 140 (2010)
Für die Überprüfung einer möglichen CPT Verletzung im komplexen
Lepton-Hadron System sind gespeicherte kalte Antiwasserstoffatome
am Besten geeignet, um vergleichende Spektroskopie und Gravitationswechselwirkung studieren zu können.
Um dieses Ziel zu erreichen, ist es notwendig, die Eigenschaften der
zur Synthese von Antiwasserstoff genutzten Wolken aus Antiprotonen
und Positronen zu charakterisieren und diese für die Erzeugung kalter tief gebundener Atome zu optimieren. Die Atrap-Kollaboration am
AD des CERN hat entsprechende Versuche durchgeführt, wobei Studien zur Temperatur dieser Teilchenwolken sowie ihrer Stabilität für
unterschiedliche Konfigurationen vorgenommen wurden.
Obwohl eingehende Versuche zum Nachweis von eingefangenen Antiwasserstoffatomen erfolgten, die innerhalb einer Ioffe-Falle produziert
wurden, konnten bislang keine statistisch signifikanten Signale detektiert werden.
Die Ergebnisse der Studien sowie die untersuchten Produktionsabläufe zum Antiwasserstoff-Einfang werden präsentiert.
Dynamics of the near threshold eta meson production in proton-proton interaction
P. Moskal, R. Czyżykiewicz, H.-H. Adam, A. Budzanowski, E. Czerwiński, D. Gil, D. Grzonka, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, K. Kilian, P. Klaja, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, B. Rejdych, J. Ritman, T. Sefzick, M. Siemaszko, M. Silarski, J. Smyrski, A. Täschner, P. Winter, M. Wolke, P. Wüstner, M. Zieliński, W. Zipper
published in: Proceedings of The 11th Workshop on The Physics of Excited Nucleons, 5?8 September 2007, Bonn, Germany
We present the results of measurements of the analysing power for the p(pol)p --> pp eta reaction at the excess energies of Q=10 and 36 MeV, and interpret these results within the framework of the meson exchange models. The determined values of the analysing power at both excess energies are consistent with zero implying that the eta meson is produced predominantly in s-wave.
Near threshold production of the pseudoscalar mesons at the COSY-11 facility
P. Moskal, R. Czyżykiewicz, H.-H. Adam, A. Budzanowski, E. Czerwiński, D. Gil, D. Grzonka, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, K. Kilian, P. Klaja, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, B. Rejdych, J. Ritman, T. Sefzick, M. Siemaszko, M. Silarski, J. Smyrski, A. Täschner, P. Winter, M. Wolke, P. Wüstner, M. Zieliński, W. Zipper
published in: Proceedings of The 11th Workshop on The Physics of Excited Nucleons, 5?8 September 2007, Bonn, Germany
We summarise measurements of the COSY-11 collaboration concerning the excitation functions of the near threshold pseudoscalar meson production in the proton-proton interaction. The results are discussed in the context of the meson-nucleon and hyperon-nucleon interactions. We conclude that the $eta$-proton interaction is significantly stronger than the eta'-proton interaction. Similarly, we found that the hyperon Lambda interacts with the nucleon considerably stronger than the hyperon Sigma, and that the interaction of (K-)-proton is much stronger than this of the (K+)-proton
Study of the hadronic production of kaon pairs below the threshold for the phi meson
P. Moskal, M. Silarski, A. Budzanowski, E. Czerwiński, R. Czyżykiewicz, D. Gil, D. Grzonka, M. Janusz, L. Jarczyk, B. Kamys, A. Khoukaz, P. Klaja, W. Oelert, C. Piskor-Ignatowicz, J. Przerwa, B. Rejdych, J. Ritman, T. Sefzick, M. Siemaszko, J. Smyrski, A. Taschner, P. Winter, M. Wolke, P. Wustner, M. Zieliński, W. Zipper, J. Zdebik
published in: Nucl. Phys. Proc. Suppl. 194 (2008) 181-182
The near threshold production of K+K- pairs in proton-proton collisions has been investigated at the cooler synchrotron COSY below and above the threshold for the phi meson using the COSY-11 and ANKE facilities, respectively. The excitation function determined for the pp ->ppK+K- reaction revealed a statistically significant enhancement close to the threshold which may plausibly be assigned to the influence of the K-p interaction. In addition, observed consistently by both groups, a strong enhancement at low values of the ratio of the K-p to K+p invariant mass distributions shows that the proton interacts much stronger with K- than with K+. In this report we focus on the measurements performed by the COSY-11 collaboration. We explain the experimental method used and present main results of completed analyses as well as a new qualitative elaboration of the ppK+K- events population on the Goldhaber plot. We conclude with the observation that event densities increase at the region where the influence from the K+K- interaction is expected.
Multimeson production in pp interactions as a background for eta and eta' decays
A. Kupść, P. Moskal, M. Zieliński
published in: Proceedings of MENU07 Conference (2008)
Multimeson production in pp interactions comprises important background for eta, omega and eta' mesons production experiments and for the studies of their decays planned with WASA detector at COSY. The available information about the reactions is summarized and the need for efforts to describe the processes is stressed.
Luminosity determination for the quasi-free nuclear reactions.
R. Czyżykiewicz, P. Moskal, E. Czerwiński, J. Klaja, P. Klaja, M. Zieliński, M. Silarski et al.
published in: AIP Conf. Proc. 950 (2007) 118-124
A method for the calculation of the luminosity for the proton-nucleus collisions based on the quasi-free proton-proton scattering is presented. As an example of application the integrated luminosity for the scattering of protons off the deuteron target is determined for the experiment of the quasi-free pn --> pneta reaction performed by means of the COSY-11 facility.
Tomografia PET/MRI przy zastosowaniu innowacyjnego mobilnego wkładu TOF-PET
B. Głowacz, M. Zieliński
published in: Inżynier i Fizyk Medyczny 5 Vol. 4 (2015) 241-244
Antimatter reveals cancer
T. Bednarski, P. Białas, E. Czerwiński, A. Gajos, T. Gruntowski, A. Gruntowski, T. Gucwa-Ryś, A. Heczko, M. Kajetanowicz, D. Kamińska, Ł. Kapłon, A. Kochanowski, G. Korcyl, J. Kowal, G. Konopka-Cupiał, T. Kozik, W. Krzemień, E. Kubicz, W. Migdał, M. Molenda, I. Moskal, P. Moskal, Sz. Niedźwiecki, M. Niedźwiecka-Pawlik, O. Rundel, Z. Rudy, P. Salabura, N. G. Sharma, M. Silarski, A. Słomski, J. Smyrski, A. Strzelecki, A. Wieczorek, M. Zieliński, N. Zoń
published in: Projektor Jagielloński 2
Mobile PET insert for simultaneous PET/MR imaging
M. Zieliński, B. Głowacz and P. Moskal
International Conference on Translational Research in Radio-Oncology | Physics for Health in Europe, 15-19 Luty 2016, Genewa, Sz
Hybrid TOF-PET/MRI local transceiver coil
B. Głowacz, M. Zieliński and P. Moskal
International Conference on Translational Research in Radio-Oncology | Physics for Health in Europe, 15-19 Luty 2016, Genewa
Study of the eta-> pi+pi-pi0 decays in p-p interactions in view of the charge conjugation invariance
M. Zieliński
12th International Workshop on Meson Production, Properties and Interaction KRAKÓW, POLAND 31 May - 5 June 2012
Matrix-PET: A novel PET detector concept based on large blocks of organic scintillators
P. Moskal, T. Bednarski, A. Heczko, M. Kajetanowicz, Ł. Kapłon, A. Kochanowski, G. Konopka-Cupiał, G. Korcyl, W. Krzemień, K. Łojek, W. Migdał, M. Molenda, S. Niedzwiecki, Z. Rudy, P. Salabura, M. Silarski, A. Słomski, J. Smyrski, J. Zdebik, M. Zieliński
PETRAD, Conference on Positron Emission Tomography in Research and Diagnostics 2012
STRIP-PET: Concept of TOF-PET scanner based on polymer scintillator strips.
P. Moskal, T. Bednarski, A. Heczko, M. Kajetanowicz, Ł. Kapłon, A. Kochanowski, G. Konopka - Cupiał, G. Korcyl, W. Krzemień, K. Łojek, W. Migdał, M. Molenda, S. Niedzwiecki, P. Salabura. M. Silarski, A. Słomski, J. Smyrski, Z. Rudy, J. Zdebik, M. Zieliński
PETRAD, Conference on Positron Emission Tomography in Research and Diagnostics 2012
Measurement of the eta->pi+pi-pi0 decay with WASA-at-COSY in pd and pp interactions
P. Adlarson, M. Zielinski
MESON 2010 - International Workshop on Meson Production, Properties and Interaction, Kraków, Poland
Title: Mobilny wkład tomograficzny TOF-PET o rekonfigurowalnej geometrii do tomografi MRI
Title in English: Mobile TOF-PET insert
Author(s): B. Głowacz, P. Moskal, M. Zieliński
Polish patent number: PL 228003
Polish patent filing date: 2015-07-16
Polish patent grant date: 2018-02-28
European patent number: EP 3323001
European patent filing date: 2018-01-14
European patent grant date: 2018-12-26
US patent number: US 10,670,737
US patent filing date: 2018-01-09
US patent grant date: 2020-06-02
