Detection Efficiency of a Continuous Dynode Electron Multiplier (Ceratron) for Positrons

Abstract

The detection efficiency of the continuous dynode electron multiplier, Ceratron, for positrons has been obtained as a function of the incident energy E _in for a slow positron beam measurement. For comparison, the efficiency curve for a channel electron multiplier (CEM) was also obtained under the same conditions. In the use of a Ceratron, the counting rate in conventional use is low compared with that under the best conditions, obtained using a new method. The dependence of the efficiency on E _in is very large for the Ceratron, but rather small for the CEM. The dependences in the low energy region for the Ceratron and for the CEM show that calibration of the efficiency on E _in for each detector is necessary in the conventional use for electrons. The detection efficiency of a Ceratron for positrons under the best conditions is almost the same as that for a CEM.