Speaker
Description
The J- PET detector, which consists of inexpensive plastic scintillators, has demonstrated its potential in the studies of fundamental symmetries [1,2] and in applications to medical physics [3,4]. In recent years, a prototype with 192 plastic scintillators arranged in 3 layers has been optimized to register the multiple annihilation photons emitted in the decays of positronium atoms (Ps) [5]. This allows performing precision tests of the discrete symmetries (C, P, T) in the decays of ortho-positronium atoms (o-Ps: triplet state of Ps) by measuring the expectation value of the odd symmetry operators consisting of the momentum vector of photons and the spin of o-Ps [2,6]. Moreover, the geometric acceptance of J- PET allows the measurement of the polarization direction of the photon based on Compton scatterings and thus, for the first time, the study of a new set of operators including the polarization of photons. Since it can measure the lifetime of o-Ps atoms, it also enables positronium imaging, which has direct applications in the medical field [3,7].
Recently, a new prototype was put into operation based on a modular design consisting of 24 individual units [8]. Each module consists of 13 plastic scintillators and can be used as a stand-alone, compact and portable detection unit. Data acquisition is performed in triggerless mode and is based on real-time data processing using the Field Programmable Gate Array (FPGA), which can process 48 data streams, each at a rate of 5Gbps [9].
At the University of Trento, a facility for the production of a bunched positron beam and positronium into vacuum has been commissioned at the Anti-Matter Laboratory (AML). With the know-how to produce transmission targets [10] (which convert positrons into positronium atoms in the forward direction) and to manipulate positronium atoms into a metastable state with increased lifetime [11], the production of Ps beam is envisaged. It is planned to move the portable modules of the J- PET detector to the AML facility to perform studies with positrons and metastable positronium atoms in defined quantum states.
The presentation will cover the main features of the J- PET detector, the modular prototype, and preliminary plans to perform studies with positron and positronium beams.
References:
[1] P. Moskal et al., Nature Communications 12 ((2021) 5658
[2] P. Moskal et al., Acta. Phys. Polo. B 47, 509 (2016)
[3] P. Moskal et al., Science Advances 7 (2021) eabh4394
[4] P. Moskal et al., Pet Clinics 15 (2020) 439
[5] K. Dulski et al., Nucl. Instrum. And Meth. A 1008 (2021) 175015
[6] A. Gajos et al., Nucl. Instrum. And Meth. A 819 (2016) 54-59s
[7] P. Moskal et al., Eur. Phys. J. C 78 (2018) 970
[8] P. Moskal et al., Phys. Med. Biol. 66 (2021) 175015
[9] G. Korcyl et al., IEEE Trans. On Medical Imaging 37 (2018) 2526
[10] S. Mariazzi et al., Phys. Rev. B 105 (11) 5422
[11] C. Amsler et al., Phys. Rev. A 99 (2019) 033405
The authors gratefully acknowledge support from the Foundation for Polish Science through programmes TEAM POIR.04.04.00-00-4204/17; the National Science Centre of Poland through grant nos. 2019/35/B/ST2/03562; the Ministry of Education and Science through grant no. SPUB/SP/490528/2021 and Jagiellonian University through project no. CRP/0641.221.2020. The authors also gratefully acknowledge the support of Q@TN, the joint laboratory of the University of Trento, FBK- Fondazione Bruno Kessler, INFN- National Institute of Nuclear Physics, and CNR- National Research Council, the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie Grant Agreement No.754496 – FELLINI and Canaletto project for the Executive Programme for Scientific and Technological Cooperation between Italian Republic and the Republic of Poland 2019-2021.
