Selection Criteria for Continuous Channel Electron Multipliers in Space Applications

摘要

Mullard multipliers were tested and classified as good, marginal or poor. Gain fatigue versus accumulated counts, pulse height distribution change during lifetime, gain degradation versus count rates, gain versus operating voltage and resolution versus operating voltage were investigated, using a tritium source. Relative efficiency versus electron energy as a function of operating voltage was measured, using a monoenergetic electron beam. From all tested devices, 25% have very low gain and do not operate as required at the end of 4 billion accumulated counts. About 40% of all devices are classified as good multipliers. They exhibit gain recovery after 3 billion accumulated counts, with progressive gain stabilizing. Multipliers classified as marginal show unexpected behavior during the lifetime, but a gain recovery phase and gain plateau region can be identified.