The Electron Multiplier as a Counter for 10-Kev Protons

Electron multipliers similar to the type described by J. S. Allen are being used as counters for low energy protons. Multipliers with electrodes made from soft beryllium copper count protons in the energy range 5 kev to 10 kev with an efficiency between 80 percent and 100 percent. Efficiencies of about 100 percent have been obtained with a radioactive alpha-source and about 0.2 percent with a RdTh gamma-source.