abstract

The SIDDHARTA-2 experiment at the DA\(\Phi \)NE collider aims to perform precision measurements of kaonic atoms X-ray spectroscopy for the investigation of the antikaon–nucleon strong interaction. To achieve this goal, novel large-area Silicon Drift Detectors (SDDs) have been developed. These devices have special geometry, field configuration, and readout electronics that ensure excellent performance in terms of linearity and stability. The paper presents preliminary results for the linearity determination and stability monitoring of the SDDs system during the measurement of kaonic deuterium carried out in the summer of 2022.

abstract

The existence of CP violation in charm-particle decays has been elusive for a long time in experiments. It was observed in 2019 in the LHCb experiment for the first time. During the LHC Run 1 and 2, the LHCb Collaboration collected a huge data sample on a scale never seen before. These data enable the most sensitive searches for CP violation ever performed. Such measurements are interpreted as precise tests of the Standard Model. The latest results achieved in charm decays are reviewed in this article. Discussion about two innovative model-independent techniques (Kernel Density Estimation and Energy Test) for searching for CP violation in charm baryons is also done.

abstract

In spatially fractionated proton therapy SFPT (also called proton grid therapy), the arrays of parallel and pencil proton beams generated by a grid collimator are applied to reduce the impact of irradiation on a healthy tissue. The irradiated skin benefits from the nonuniform profile of the beam causing faster repair of irradiated tissues. At the same time, due to the Multiple Coulomb Scattering MCS of the proton beam, the deeply situated target volume can be uniformly irradiated. In this paper, an attempt is undertaken to design Spread-Out Bragg Peak (SOBP) at the target depth from the set of beams generated by the grid collimators. Within these studies, the designed grid collimator and energy modulators were tested to form SOBP from spatially fractionated proton beams.

abstract

In this contribution, a concept for a new phantom for positronium imaging with PET scanners is described. The proposed phantom is based on the NEMA IEC phantom in which six high-activity spheres are filled with solutions characterized by a different mean ortho-positronium lifetime. A method for controlling ortho-positronium lifetime is discussed along with preliminary results. The XAD4 suspended in various fractions of water was tested as a potential model of a sample with a controlled mean lifetime of ortho-positronium. The mean lifetime of ortho-positronium for six samples was estimated by means of the Positronium Annihilation Lifetime Spectroscopy (PALS). Obtained spectra were fitted with the PALS Avalanche analysis program and components corresponding to the ortho-positronium annihilation in the XAD4 pores were established. As a result, the correlations between the lifetime and production intensity of ortho-positronium and the concentration of XAD4 in water were determined.

abstract

The biopolymer matrix synthesized from epoxidized soybean oil (AESO) and vanillin dimethacrylate (VDM) in a molar ratio of 1:1 was investigated by the Positron Annihilation Lifetime Spectroscopy (PALS) in the presence of pure water, saline solution, and water contaminated with xenobiotics from a reservoir. The main aim of the research is the construction of a biosensor with a biopolymer matrix for the detection of trace water pollution with xenobiotics, which are carcinogenic and have a negative impact on the human endocrine system. These substances may come from the pharmaceutical industry, households, and are used as plant protection products or food additives. The measurements show that the presence of ions and pollution in water causes the elongation of the absorption process into the matrix. The performance of the biosensor will therefore correlate with the level of ion concentration and pollution.

abstract

The Jagiellonian Positron Emission Tomograph (J-PET) is the first plastic scintillator-based tomographic device used to test discrete symmetries in the charged leptonic sector. One of such tests is for the CPT symmetry, under the combined transformation of charge, parity, and time reversal in the decays of positronium atoms. J-PET performed its first measurement for the CPT symmetry test by searching for non-vanishing CPT-violating angular correlations between the spin and orientation of the decay plane of ortho-positronium (o-Ps) atoms, which is the triplet state of positronium. The sensitivity of testing CPT symmetry with the J-PET detector reaches the precision level of 10\(^{-4}\). Here, we will discuss the prospects of improving the sensitivity of this test beyond the level of 10\(^{-4}\) by enhancing the photon registration efficiency using a new layer of densely packed plastic scintillators and a spherical annihilation chamber as a positronium production medium.

abstract

Positron emission tomography (PET) is essential in medical diagnostics and monitoring therapy. The J-PET Collaboration at Jagiellonian University is developing a new generation of Total-Body PET scanners based on plastic scintillators. One of the Total-Body J-PET designs comprises seven rings, each consisting of 24 modules. A single module is built of 2 layers, each comprises of 16 axially arranged plastic scintillator strips of 330 mm length, read out by silicon photomultiplier (SiPM) arrays from both ends, and an additional layer of 50 wavelength shifter (WLS) bars, placed perpendicular to plastic layers. This study estimates the scatter fraction of the Total-Body J-PET manufactured from plastic scintillator strips according to the NEMA NU 2-2018 standards by using the GATE software. The scatter phantom was simulated as a solid cylinder with a length of 700 mm and an outside diameter equal to 203 mm. At the same time, at a radial distance of 45 mm, we have a hole with a diameter of 6.4 mm where a linear source with total activity of 1 MBq is placed. For data processing, sinograms were generated, and the Single Slice Rebinning (SSRB) algorithm was used for the scatter fraction calculation. As a result, we estimate that addition of the WLS layer is increasing the scatter fraction by 0.67%.

abstract

We present building blocks that make up the software stack being developed as part of the Dose-3D project that aims at constructing a next-generation active medical phantom for spatial therapeutic dose distribution reconstruction. The architecture of the custom G4RT application is discussed, and Python-based packages for high-level data processing and analysis are introduced.

abstract

We present an analysis of the characteristics of a therapeutic photon beam simulated by the G4RT simulator which is based on the Monte Carlo method. Development of the G4RT is a part of the Dose-3D project. In order to verify the reliability of the implemented simulator, spatial dose distributions were compared with the real measurements and results from the PRIMO simulator. For the purpose of assessment, the primary photons analysis was performed. Results show the reliability of the G4RT. Therefore, the simulator can be used in further research.

abstract

The positronium atom, a bound state of electron and positron, is a suitable leptonic test site for Charge-Parity (CP) discrete symmetry research. According to the Standard Model, the photon–photon interaction in the final state due to the vacuum polarization may mimic CP violation of the order of \(10^{-9}\), while weak interaction effects lead to a violation of the order of \(10^{-14}\). So far, the experimental limits on CP symmetry violation in the decay of o-Ps are set at the level of \(10^{-3}\). The J-PET detector can be used to explore discrete symmetries by looking for probable non-zero expectation values of the symmetry-odd operators, constructed from spin of ortho-Positronium (o-Ps) and momentum, and polarization vectors of gamma (\(\gamma \)) quanta resulting from o-Ps annihilation. The upgraded version of the J-PET detector, with an additional fourth layer of detection modules increases signal acceptance, which allows to triple the efficiency of \(\gamma \) quanta detection for CP discrete symmetry studies.