Photomultiplier Selection Criteria for Satellite Experiments

Forty-six RCA C 7151 Q photomultiplier tubes and thirty-five EMI 9711 NB photomultiplier tubes have been tested for use in the telescope of the COS-B gamma-ray experiment. The tubes were selected taking into account gain, linearity, fatigue behaviour and temperature characteristics. Besides identifying the most suitable tubes for this application, the experimentally determined values make it possible to derive "typical" behaviour parameters which can be used to pre-select tubes at the ordering stage. The results obtained with the EMI tubes clearly demonstrate a striking difference between "typical" catalogue values and "typical" measured values for the batch tested.