Studies of light and charge produced by alpha-particles in high-pressure xenon

The results of measurements of scintillation light induced by alpha-particles in high-pressure Xe are presented. The ratio of Nex/Ni, and the intensity and time characteristics of the luminescence signal have been measured for different densities up to 0.74 g/cm3. The role and mechanisms of the electron-ion recombination in high-pressure gas have been investigated. The existence of clusters and self-trapped excitons above 0.6 g/cm3 has been observed and discussed. This work is a part of a development program of high-pressure Xe detectors for low-energy gamma rays