Persistent Metastable States and the Inhibited Scintillation of He II

Abstract

The scintillation of liquid helium produced by $\alpha$ particles has been measured with particular emphasis on the temperature region below 1.25°K which had not been studied previously. An interpretation of the observed inhibition of the scintillation below $T_{\lambda }$ is proposed which attributes the effect to a reduced radiative destruction rate of metastable states in He II.