Absolute Energy to Produce an Ion Pair in Various Gases by Beta Particles fromS35

A repetition has been carried out of recent experiments in which the absolute average energy $W_{\beta }$ required to form an ion pair in various gases was determined for the beta particles from ${\mathrm{S}}^{35}$. The present experiments employ a new procedure, which eliminates almost entirely large correction terms necessary in the former ionization measurements. The two experiments are in good agreement and yield the modified values of 35.0, 24.6, and 33.9 ev/ion pair for $W_{\beta }$ for ${\mathrm{N}}_2$, ${\mathrm{C}}_2$ ${\mathrm{H}}_6$, and air, respectively.