Author/Authors :
Araْjo، نويسنده , , H.M. and Bewick، نويسنده , , A and Davidge، نويسنده , , D and Dawson، نويسنده , , J and Ferbel، نويسنده , , T and Howard، نويسنده , , A.S and Jones، نويسنده , , W.G and Joshi، نويسنده , , M and Lebedenko، نويسنده , , V and Liubarsky، نويسنده , , I and Quenby، نويسنده , , J.J and Sumner، نويسنده , , T.J and Neves، نويسنده , , F، نويسنده ,
Abstract :
A set of 35 photomultiplier tubes (ETL D730/9829Q), intended for use in the ZEPLIN III Dark Matter detector, was tested from room temperature down to −100°C, with the aim of confirming their suitability for detecting xenon scintillation light at 175 nm while immersed in the cryogenic liquid. A general improvement of both gain and quantum efficiency at the xenon scintillation wavelength was observed with cooling, the best combined effect being 40%, while little change was noted in the timing properties and dark current. Saturation of response due to accumulation of charge in the resistive bialkali photocathodes was seen at an average photocurrent of 108 photoelectrons/s for the device with best quantum efficiency, whereas an order of magnitude higher current was required to saturate the least sensitive one. Variations in photocathode thickness from tube to tube could account for this behaviour, as well as the fact that the quantum efficiency improves the most for devices with poorest efficiency at room temperature.
