Monte Carlo simulation study of the characteristics of Xe-Ne gas mixtures as detection media in gas proportional ionization counters

A Monte Carlo simulation has been developed in order to assess the use of Xe-Ne gas mixtures as detection media in gas proportional ionization counters, examining in particular the parameter most relevant for the performance of a detection medium: the intrinsic energy resolution R/sub int/. This parameter, which establishes a theoretical limit to the detection capability of a detector, has been calculated as a function of the mixtures composition. The Monte Carlo simulation code developed fully reproduces the growth of single-electron-initiated avalanches in cylindrical geometry and results for R/sub int/ are discussed in terms of the parameter f, the statistical fluctuations parameter characterizing single-electron-avalanches. This parameter is calculated for each mixture as a function of the reduced anode voltage K=V/ln(c/a), where V is the voltage applied to the anode-wire and c/a is the cathode-to-anode radius ratio. Results for the gas multiplication factor M, characterizing each mixture composition at a given applied electric field, were also obtained.