Measurements of photoelectron extraction efficiency from CsI into mixtures of Ne with CH4, CF4, CO2 and N2

Experimental measurements of the extraction efficiency f of the UV-induced photoelectrons emitted from a CsI photocathode into gas mixtures of Ne with CH4, CF4, CO2 and N2 are presented; they are compared with model-simulation results. Backscattering of low- energy photoelectrons emitted into noble gas is significantly reduced by the admixture of molecular gases, with direct impact on the effective quantum efficiency. Data are provided on the dependence of f on the type and concentration of the molecular gas in the mixtures and on the electric field.