ForewordPhotomultipliers are extensively used in scintillation counting for the detection and analysis of ionizing radiation. The utilization of these detectors in a variety of technical disciplines have made standard test procedures desirable so that measurements may have the same meaning to all manufacturers and users.This standard is not intended to imply that all tests and procedures described herein are mandatory for every application@ but only that such tests as are carried out on photomultipliers for scintillation and Cerenkov counting should be performed in accordance with the procedures given in this document.