Development of a computational model of an extrapolation camera for use in beta and gamma dosimetry

With technological advancement in the area of ionizing radiation metrology, several questions have arisen about the absorbed dose due to beta radiation. Several existing radionuclides are beta and electromagnetic (gamma) emitters, and in many cases the absorbed dose due to beta radiation exceeds the dose corresponding to the gamma rays. The search for new methodologies for dose measurement and absorbed dose rate due to beta radiation is necessary. The use of computational tools has allowed significant advances in the optimization of measurement systems, since besides facilitating and accelerating the analysis, it allows simulating and evaluating the influence of different parameters in isolation. In addition, it is possible to study new technologies and/or methodologies for the creation of measurement systems. The Monte Carlo Method (MMC) mathematical method was used to theoretically simulate statistical processes. This mathematical method uses a sequence of random numbers to perform a simulation of the physical phenomenon. Monte Carlo computational code MCNPX (Monte Carlo N-Particle eXtended) was used for modeling and simulation of the extrapolation chamber. This code takes into account radiation-matter interaction libraries and is internationally recognized as an efficient code for transport analysis of various types of radiation. The objective of this work is to develop a computational model of the extrapolation chamber model PTW-23392 and to obtain a validated computational model. Validation will be made by comparing the results obtained published in the literature versus values obtained through computer simulation. The extrapolation chamber was positioned 30 cm in relation to the radiation source. The source used in the simulations was ⁸⁵Kr, which is a beta particle emitter with a maximum energy of 0.687 MeV and a half life of 10.7 years