Gas amplification in isobutane and P10 filled gas counters

Gas amplification factors have been measured for isobutane and P10 gases in single wire proportional counter and parallel plate avalanche counter geometries for reduced field strength value ranging from 140 to 1000 V cm −1Torr −1. Data using the SWPC were found to satisfy the Aoyama formula for gas amplification with m = 0 and also the Diethorn formula. The PPAC data are satisfactorily described again, by the Aoyama formula with m = 0 as well as by the Zastawny formula. The values of the relevant parameters in the formulae used have also been extracted from the fits.