Generation of SQS in quenching gas (CH/sub 4/) of proportional counter and related problems

Two topics on the phenomena in proportional counters are reported. One is the observation of the SQS transition in pure methane gas under irradiation by 4.5-keV X-rays. The effect of a small amount of argon on the SQS transition was investigated with gas mixtures (CH/sub 4/:Ar) at various mixing ratios. The SQS transition was not observed in pure methane gas, although it was observed still in the gas mixture of 99.8:0.2. The other was the measurement of electron drift characteristics with a single-wire gas counter operated in the SQS transition regions. The counter gas used was a mixture of argon and methane to which ethanol vapor was added. From a comparison with the proportional mode, the use of the SQS mode is recommended to obtain a better time resolution in the application of drift counters.<
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