Method for the determination of photomultiplier collection efficiency, F

Photomultiplier collection efficiency, F, is a fundamental, but difficult, parameter to measure with certainty. A method for its determination, based on the gain of the first dynode, has been devised and applied to two different types of photomultiplier. The measurements are substantially free from the sources of error, which have compromised previously reported results by other authors. F may be determined by the proposed method with an accuracy of better than +/-3% for any photomultiplier tube with sufficient gain to uncover its single electron response.