Simulation of Experiments with Pressurized-Xenon γ-Ray Detectors

Abstract

A γ-ray detector based on pressurized xenon is described, and the characteristics of the processing of the spectrum of the detector are examined. It is shown that the SpectraLine computer program, where these characteristics are taken into account, makes it possible to process successfully the spectra measured with a pressurized-xenon detector, which greatly expands the possibilities of instruments of this class for performing spectrometric measurements. The possibilities of using pressurized-xenon detectors to solve complex problems of gamma-spectrometric analysis using the GammaLab program system are analyzed. The results obtained show that it is indeed possible, in principle, to use a pressurized-xenon detector together with the SpectraLine computer program for quantitative analysis of samples with a complex radionuclide composition, specifically, to determine the isotopic composition of plutonium.For a long time now, the Monte Carlo method has been used successfully to simulate spectra. One application developed on the basis of this method is the virtual gamma-spectrometric laboratory GammaLab [1, 2], which makes it possible to simulate the spectra obtained for point and volume sources with an arbitrary radionuclide composition using semiconductor and scintillation detectors. The resolution of the new detectors, based on LaBr, LaCl, or pressurized xenon and developed at the Moscow Engineering Physics Institute [3,4], is lower than that of detectors based on ultrapure germanium, but they are free of drawbacks such as the need for low-temperature cooling and high cost, and their resolution is approximately 5 times higher than that of NaI scintillation detectors.The present article analyzes the possibilities of using gamma spectrometers based on pressurized xenon for quantitative analysis of samples with a complex radionuclide composition using the GammaLab program system and presents the principles and results of the simulation of experiments using a pressurized-xenon gamma-ray detector.The simulation consists in calculating the radiation spectrum of a source at the position of the detector, converting the spectrum taking account of instrumental effects, and transferring it into an external program for display and further processing. A possible variant of a solution of this problem is to use the Monte Carlo method to play out the decay chain of the radionuclide and radiation transfer in the container and detector materials. This method leads to long calculations of the spec-

Determination of the response function of the NaI detector for g-quanta with an energy of 4.43 MeV, formed during inelastic scattering of neutrons with an energy of 14.1 MeV on carbon nuclei

“…Experimental acquisition of the response function requires a significant number of sources of monoenergetic gamma radiation and takes a long time. Therefore, in recent years, the Monte Carlo method has become widespread for calculating the response function of detectors [1][2][3][4][5]. Determination of the detector response function in a wide range of gamma-radiation energies is necessary for the correct interpretation of experimental data and for calculating the characteristics of the devices being developed for recording nuclear radiation [6].…”