engleski

Comparative study of TE gases and DME in a proportional counter

We performed a comparative study of propane, propane-based TE gas, isobutane, isobutane-based TE gas and DME in a proportional counter. The mean gas amplification factor and the statistical fluctuations of the gas amplification, the energy resolution, the W value and the Fano factor were measured. From the measured gas gain data, the first Townsend ionization coefficient was determined. It is shown that in a cylindrical proportional counter electrons do not reach the equilibrium with the electric field at rather moderate electric field strengths. The relative variance of the single electron spectra increases with the gas gain, but remains <1 over the whole gas gain range. The W value for photons in DME (24.6 eV) is presented for the first time. In pure DME the count rate was much lower and the energy resolution worse than in other gases. DME was also much more sensitive to small contamination due to outgassing than other gases were.

DME; TE gas mixtures; proportional counter; single electron spectra; gas amplification; W value; energy resolution; Fano factor

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