Geant4 code for simulation attenuation of gamma rays through scintillation detectors

Response characteristics of MAPbBr3 direct conversion X-ray detectors based on measurements and Monte Carlo simulation

In recent years, higher requirements have been placed on the response characteristics of X-ray detectors in the field of medical diagnostic imaging. Due to this, high sensitivity, high attenuation coefficient and low cost detection materials need to be developed. In this paper, the geometric model of a detector was established by Geant4 code. The absorption efficiency and mass attenuation coefficient of MAPbBr3 crystals were calculated in the energy range of 30 keV to 100 keV. Compared with the mass attenuation coefficient of the NIST database, the deviation was within 1.39%. The signal charge number and detection sensitivity of the X-ray interaction with the MAPbBr3 crystal ware calculated. Compared with the CdTe crystal and α-Se, the MAPbBr3 crystal still had a larger detection sensitivity under a smaller applied electric field, which was approximately 9 times higher than that of α-Se. This result indicated that the detection sensitivity could be greatly improved by using a high atomic number and high charge mobility-lifetime product. Based on the simulation results, the 2 mm thick MAPbBr3 crystal exhibited the highest detection sensitivity at 60 keV X-rays, which was in agreement with the experimental results.

Investigation of gamma shielding and liquid permeability properties of kaolin for liquid radioactive waste management

Gamma radiation shielding and liquid permeability coefficient of baked and unbaked kaolin powder were experimentally and theoretically investigated. A NaI(Tl) detector was used to measure attenuation properties of the samples. The experimental values for the linear coefficient were validated by theoretical values using WinXCOM software. The results established that unbaked kaolin with density 2.65 g/cm³ yielded highest mass attenuation coefficients of 0.0736 cm²/g, 0.0561 cm²/g and 0.0527 cm²/g for 661.7, 1173.2 and 1332.5 keV respectively and liquid permeability coefficient of 2.33 x 10 ^-12 m/s. The study concludes that compacted unbaked kaolin be considered a valid alternative for radiation shielding due to its low liquid permeability coefficient for liquid radioactive waste management.

The Influence of Titanium Dioxide on Silicate-Based Glasses: An Evaluation of the Mechanical and Radiation Shielding Properties

The mechanical and radiation shielding features were reported for a quaternary Na₂O-CaO-SiO₂-TiO₂ glass system used in radiation protection. The fundamentals of the Makishima-Mazinize model were applied to evaluate the elastic moduli of the glass samples. The elastic moduli, dissociation energy, and packing density increased as TiO₂ increased. The glasses' dissociation energy increased from 62.82 to 65.33 kJ/cm³, while the packing factor slightly increased between 12.97 and 13.00 as the TiO₂ content increased. The MCNP-5 code was used to evaluate the gamma-ray shielding properties. The best linear attenuation coefficient was achieved for glass samples with a TiO₂ content of 9 mol%: the coefficient decreased from 5.20 to 0.14 cm^-1 as the photon energy increased from 0.015 to 15 MeV.