Measurements of wavelength-dependent double photoelectron emission from single photons in VUV-sensitive photomultiplier tubes

摘要

Measurements of double photoelectron emission (DPE) probabilities as afunction of wavelength are reported for Hamamatsu R8778, R8520, and R11410VUV-sensitive photomultiplier tubes (PMTs). In DPE, a single photon strikes thePMT photocathode and produces two photoelectrons instead of a single one. Itwas found that the fraction of detected photons that result in DPE emission isa function of the incident photon wavelength, and manifests itself below$\sim$250 nm. For the xenon scintillation wavelength of 175 nm, a DPEprobability of 18--24\% was measured depending on the tube and measurementmethod. This wavelength-dependent single photon response has implications forthe energy calibration and photon counting of current and future liquid xenondetectors such as LUX, LZ, XENON100/1T, Panda-X and XMASS.