The effect of electron multiplication on the electroluminescence yield of pure xenon and xenon-neon gas proportional scintillation counters: experimental and simulation results

In applications of the gas proportional scintillation counter to the detection of very low energy X-rays, the addition of the light noble gas neon to the usual xenon filling improves the collection of primary electrons that would have originated near the detector window. However, xenon-neon mixtures produce lower electroluminescence yields than pure xenon. The highest electroluminescence yield that can be achieved without jeopardizing the energy resolution is limited by the additional fluctuations introduced by electron multiplication and, consequently these detectors are usually operated at reduced electric fields below the ionization threshold. In this work, a compromise between electroluminescence output and energy resolution is investigated for xenon-neon mixtures at a total pressure of 800 Torr (with 5%, 10%, 20%, 40%, 70%, 90% and 100%Xe), and for 5.9 keV X-rays. Using experimental and Monte Carlo studies, the effects of introducing a limited amount of charge multiplication on the electroluminescence yield and on the detector energy resolution are analysed and discussed, and the optimum operating conditions for gas proportional scintillation work are established