IMPROVED PHYSICAL AND MATHEMATICAL MODEL OF A SEMICONDUCTOR GAMMA RADIATION DETECTOR BASED ON THE USE OF THE STATISTICAL TESTS METHOD
Relevance of research. The relevance of the study is due to the fact that neutron activation analysis (NAA) is one of the convenient ways to determine the composition of samples of natural and man-made origin. Among such objects are unique samples of rocks, minerals, condensates, dust, "hot" particles, etc. In this case, the effectiveness of the analysis depends on the applied methods and techniques. NAA is highly sensitive (up to 10<sup>-14</sup> g), multi-element, non-destructive, less dependent on the mass and composition of the sample, on the forms of finding the elements. The main aim: the main purpose of the study was to obtain an HPG model of the detector using Monte Carlo simulation of the interaction of gamma-rays with the detector crystal. Research objects: the detector response was obtained experimentally and with the help of a neutron-physical model. Research Methods. The main tool used for instrumental neutron activation analysis is a semiconductor detector based on highly pure germanium crystals under the general label HPGe (HPG). This paper is devoted to modeling one of these detectors using the Monte Carlo method and the MCNP program that implements it. Results. In the course of research, in particular: a) a large number of experimental measurements were made with a Canberra GC1518 semiconductor detector using a set of standard sources at various distances and angles of rotation, b) variant models were created, c) parametric modeling was performed, d) analysis was performed and conclusion was made on the sensitive crystal volume of the detector. A model has been developed that repeats the parameters of a real gamma-spectrometer, which makes it possible to calculate the efficiency of recording gamma-rays in a wide range of energies up to 1.5 MeV.