Energy resolution of xenon proportional counters: Monte Carlo simulation and experimental results

The gas multiplication factor M and energy resolution R of xenon gas cylindrical proportional counters are investigated experimentally and calculated theoretically using a Monte Carlo technique to simulate the growth of single-electron-initiated avalanches. A good agreement is found between calculated and experimental data. The experimental and the calculated results are presented as a function of the reduced voltage K and the reduced anode radius Na, where N is the number density and a the anode radius. The Monte Carlo results for the intrinsic energy resolution Rint are discussed in terms of the parameter f which characterizes the statistical fluctuations of the avalanche gains. The present calculations have revealed that there is an intrinsic dependence of f on the critical value Sc of the reduced electric field at the onset of multiplication. This has enabled the parameterization of f and of the intrinsic energy resolution Rint in terms of the reduced voltage K only and has explained why, for a given range of operating values for M, energy resolution in a cylindrical proportional counter is improved for thinner anode wires and lower pressure

Simulation and experimental results for the detection of conversion electrons with gas proportional scintillation counters

The application of gas proportional scintillation counters (GPSC) to the detection and identification of conversion electrons in the medium energy range is investigated. Experimental and Monte Carlo results are presented for the response of a xenon GPSC, filled at atmospheric pressure, to the decay of a 109Cd source. This source emits 88.0 keV [gamma]-rays, eL=84.6 keV and eK=62.5 keV conversion electrons, as well as fluorescence X-rays and Auger electrons. Good agreement is found between the measured and the calculated energy spectra. The response to higher-energy electrons is investigated by Monte Carlo simulation, by considering a hypothetical GPSC filled with xenon at 10 atm and doped with the 133mXe metastable isotope. The calculated energy spectra for the absorption of the 133mXe 233.2 keV [gamma]-rays, eK=198.6 keV and eL=228.4 keV conversion electrons, as well as fluorescence X-rays and Auger electrons, are presented and discussed.http://www.sciencedirect.com/science/article/B6TJM-3YS91CB-J/1/4b48a2a89f10ac68be0e04c4537a9d5