Experimental study of non-linear effects of photomultiplier gain

Abstract

The experimental apparatus and the results of a study on the gain variation of photomultipliers at high average anode current are described. This gain variation was found to depend on the secondary emission process on dynodes; the last dynode gives the largest contribution to the overall photomultiplier effect. This contribution has been isolated and measured. The phenomenon may be due to more than one physical effect. The dominant one turns out to depend on the power released on the dynode by the incident electrons. A physical model is discussed which can take into account the observed phenomena.