A feasibility study of ortho-positronium decays measurement with the J-PET scanner based on plastic scintillators

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 decays with angular and energy resolution equal to and , 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 pile-ups, thus enabling compensation of the lower efficiency of the plastic scintillators by performing measurements with higher positron source activities.

QED and Fundamental Symmetries in Positronium Decays

“…The large relative error on the experimental decay rates in Eqs. (3,4) for o-Ps and Eq. (9) for p-Ps compared to the QED theory uncertainties in Eqs.…”

“…with the o-Ps produced in SiO 2 powder, whereas Vallery et al [31] found Γ = 7.0404 ± 0.0010 ± 0.0008 × 10 6 s −1 (4) working in vacuum. These results are consistent with the QED theory prediction, Eq.…”

“…With a new generation of positronium experiments coming on-line [1,2,3] it is valuable to review the present status of theory and constraints from other processes on the key observables. This we present here, with main emphasis on physics experiments [1,4,5] that can be performed using the new J-PET detector, Jagiellonian Positron Emission Tomograph, being built in Cracow [6]. The J-PET is a new PET device based on plastic scintillators designed for total body scanning in medicine as well as biological applications [7] and fundamental physics research [1] with detection of positronium and (from its decay products) Compton rescattered photons in the detector.…”

Feasibility of Ortho-positronium Lifetime Studies with the J-PET Detector in Context of Mirror Matter Models

“…The J-PET (Jagiellonian-Positron Emission Tomography scanner) is a high acceptance multi-purpose detector optimized for the detection of photons from positron-electron annihilation. Originally designed as a medical scanner, the J-PET detector has several advantages such as very good timing resolution [31], possibility of data taking in the continuous mode (triggerless) [32,33], fully digital front-end electronics [34], and efficient discrimination between different Ps decay channels [35]. These make it suitable in a broad scope of interdisciplinary investigation, e.g.…”

New Porosimetric Method Based on the 3γ Annihilation Rate. Applications to Materials Science and Medical Imaging

“…In order to apply the proposed 3γ fraction to follow changes in material structure, the PET scanners should be equipped with the 3γ coincidences system. The innovative tomography PET scanner allowing for the multi photon measurements is nowadays constructed by J-PET collaboration [21,22]. It enables the diagnosis based on positron and positronium lifetime [23] as well as the one based on the ratio of 3γ and 2γ annihilation rates [24].…”