SUSTENANCE OF A GAS-FILLED DELTA-E-COUNTER AT SUBATMOSPHERIC PRESSURES FOR MORE THAN 150 DAYS

The long-term sustenance of the performance of a metal body Delta E-ga s counter filled to subatmospheric pressures is extended from our prev ious study. This has been possible by introducing within the counter v olume an iron-oxide based catalyst that can efficiently reduce the pre sence of electronegative impurities. By this means the gas counter can be continuously operated for more than five months with minimal peak channel shift and good resolution. Initially the counter was kept in t he atmospheric environment which led to a slow decrease in peak channe l, but subsequently when it was operated in vacuum environment the pea k channel starts to appreciate and ultimately saturates at the initial value. The resolution (%) also remains steady around 11-13%. Various other factors determining the counter performance viz., efficiency, sh ape of the peak etc., are also studied. The experiment is carried out both for stainless steel and aluminum body counters.