A study of the scintillation light induced in liquid xenon by electrons and alpha particles

The time dependence and the intensity of the primary scintillation light in liquid xenon excited by ²⁴¹Am alpha particles and ²⁰⁷Bi internal conversion electrons were measured at different electric field strengths. High-purity liquid xenon was used to fill a parallel-plate ionization chamber equipped with a CaF₂ window coupled to a UV (ultraviolet) sensitive photomultiplier tube. The effect of the specific ionization density on the scintillation light as well as the time correlation between the light signal and the charge signal is reported. It is demonstrated that the fast scintillation signal produced in liquid xenon by an ionizing particle provides an ideal trigger in a detector aiming at a complete three-dimensional event reconstruction with an excellent background rejection capability