Properties of liquid xenon scintillation for dark matter searches

The scintillation yields and decay shapes for recoil Xe ions produced by WIMPs in liquid xenon have been examined. A quenching model based on a biexcitonic diffusion-reaction mechanism is proposed for electronic quenching. The total predicted quenching, nuclear and electronic, is compared with experimental results reported for nuclear recoils from neutrons. Model calculations give the average energy to produce a vuv photon, Wph, to be ∼75 eV for 60 keV recoil Xe ions. Some aspects of ionization relating to liquid xenon WIMP detectors are also discussed.