To measure luminescence yield an integrator of pulses by photomultiplier tube-amplifier-discriminator system serving as the light detector is often used. In the present work the performance of an integrator is compared with that of a photon counting (PC) system which is also used for the same purpose. A PC system is found to be more suitable in measurement of luminescence yield and decay time. Furthermore, the values of yield and decay time is seen to be best obtained when PC is achieved by using a multichannel scaler (MCS). However, before adapting an MCS based PC system for these measurements it is necessary to establish the single photon response of that system. The performances of these systems have been evaluated from experiments done on lyoluminescence of mannose irradiated by γ-ray to 550 Gy.