Study of Metastable Population Density in a Hollow Cathode Helium Discharge

Abstract

The population density of metastable helium atoms is experimentally investigated in a hollow cathode discharge. The metastable population density measured using laser absorption spectroscopy is proportional to the square root of electron density under conditions of constant electron temperature and a constant neutral density. Calculation based on a collisional-radiative model and diffusion loss indicates that metastable population density is linearly proportional to electron density.