Plastic scintillators are widely used in various radiation measurement applications, and the use of plastic scintillators for nuclear applications including decommissioning, such as gamma-ray detection and measurement, is an important concern. With regard to efficient and effective gamma-ray detection, the optimization for thickness of plastic scintillator is strongly needed. Here, we elucidate optimization of the thickness of high-performance plastic scintillator using high atomic number material. Moreover, the EJ-200 of commercial plastic scintillators with the same thickness was compared. Two computational simulation codes (MCNP, GEANT4) were used for thickness optimization and were compared with experimental results to verify data obtained by computational simulation. From the obtained results, it was confirmed that the difference in total counts was less than 10% in the thickness of the scintillator of 50 mm or more, which means optimized thickness for high efficiency gamma-ray detection such as radioactive 137Cs and 60CO. Finally, simulated results, along with experimental data, were discussed in this study. The results of this study can be used as basic data for optimizing the thickness of plastic scintillators using high atomic number elements for radiation detection and monitoring.
The Secondary Photoelectron Effect: Gamma Ray Ionisation Enhancement in Tissues from High Atomic Number Elements