Energy resolution of xenon proportional counters: Monte Carlo and experimental results for 5.9 keV X-rays

The energy resolution, R, of xenon filled cylindrical proportional counters is investigated experimentally for 5.9 keV X-rays and 10 and 47.5 /spl mu/m anode wires, and calculated theoretically using a Monte Carlo simulation technique based on first principles with no adjustable parameters. The gas multiplication factor, M, is also measured experimentally and calculated using the same Monte Carlo technique. Good agreement is in general found between the experimental and the calculated values for R and M. It is shown that better energy resolutions are achieved for the thinner anode wire. The Monte Carlo results for R are expressed in terms of a parameter that characterizes the statistical fluctuations in the number of electrons in single-electron initiated avalanches, the parameter f. These calculations have given evidence that f depends mainly on the critical reduced electric field, S/sub 0/, at the onset of multiplication.