Proportional light in a dual-phase xenon chamber

A dual-phase xenon chamber was tested to measure the yield of electrons extracted from the liquid to the gas and their subsequent amplification via proportional light. The light yield was studied as a function of electric field and gas pressure. A UV-sensitive compact metal channel photomultiplier tube, placed in the gas above the liquid xenon, was used for these measurements. An electron lifetime of at least 1.5 ms was inferred from a measurement of the ionization signal, triggered by the primary scintillation light, with the same chamber operated in single phase.