Speaker
Description
Primary scintillation in Xe for electrons and alpha-particles Content Gaseous xenon (GXe) is playing an increasingly significant role in important areas of neutrino physics such as double beta decay and double electron capture experiments and is a potential alternative to MeV-region γ-ray imaging. The precise knowledge of the xenon response to radiation interactions in both scintillation and ionization channels is of utmost importance for the exact understanding and modulation of xenon radiation detectors. The primary scintillation yield, i.e. the mean energy required to produce a scintillation photon, wsc, of GXe is far less understood than the ionization yield due to the limited number of studies in the literature. While for 5.5-MeV α-particle interactions the wsc-value was measured to be in the 34-60 eV range, for electrons, measuring the primary scintillation produced by x- and γ-ray interactions, the wsc-value was measured to be in the 61 - 111 eV range. The average energy expended per excited atom in GXe is expected to be similar for x-, γ-rays or electrons and almost equal to that obtained for α-particles. However, the results presented in the literature are inconsistent with that expectation and not fully understood, as can be only partially ascribed to the different gas density and/or drift field conditions. One may also pose the question of a dependence of wsc with photon energy. We carried out a systematic study on the absolute primary scintillation yield in Xe under reduced electric fields in the 70–300 V/cm/bar range and near atmospheric pressure, 1.2 bar, using a Gas Proportional Scintillation Counter. Our results are supported by a robust geometrical efficiency simulation model. Our experimental wsc-values agree with both state-of-art simulations and literature data obtained for α-particles.
