Electric Field Quenching of Metastable2S01Helium

Abstract

We have measured the transition rate of the normally metastable helium $2^{1}S_{0}$ state in the presence of a uniform electric field by observing the attenuation of a metastable beam of helium passing between parallel electric field plates. This attenuation, when combined with our measurement of the velocity distribution of the beam, yields a transition rate of $(0.926\ifmmode\pm\else\textpm\fi{}0.020){F}^{2}$ ${\mathrm{sec}}^{\ensuremath{-}1}$, where $F$ is the field strength in kV/cm. This agrees well with our calculated value of $(0.920\ifmmode\pm\else\textpm\fi{}0.030){F}^{2}$ ${\mathrm{sec}}^{\ensuremath{-}1}$ which is derived from a sum of oscillator strengths published by various workers.