Photomultiplier collection efficiencies and nonpoissonian pulse height distributions

Collection efficiencies have been measured for RCA type 8850 and 8852, and EMI type 9558, photomultipliers. Apart from their immediate application to the measurement of absolute light intensities, it is shown that the results yield information relating to the process of secondary emission at the multiplier dynodes, and the formation of nonpoissonian pulse height distributions.