Speaker
Description
Experiments used for rare-event searches have seen an impressive increase of sensitivity over the past decades. Among the most sensitive detector types used in direct dark matter searches are dual-phase xenon time projection chambers (TPCs). To develop a signal model for such detectors, the response of the medium to interactions of different particle types needs to be known to a high accuracy. While several measurements for interactions of electrons, photons and neutrons were reported in the past, the literature is sparse when it comes to the interaction of alpha particles with liquid xenon.
The Heidelberg Xenon (HeXe) dual-phase xenon TPC has been used to study the relative scintillation and ionization yield of low energy electrons from a $\mathrm{^{83m}Kr}$ source, as well as from alpha particles emitted by dissolved $\mathrm{^{222}Rn}$. Furthermore, a measurement of the electron drift velocity has been carried out. The different electric field configurations applied during the measurements were simulated by a detailed three dimensional model of the TPC using COMSOL Multiphysics. The measurements span over a wide range of fields within 7.5$\,$V/cm up to 1.64$\,$kV/cm, whereas special emphasis was put on the low-field regime.
