Measurement of PMT charge nonlinearity using the continuous light attenuation method

We use a continuous neutral density attenuator to investigate the photomultiplier tube (PMT) charge nonlinearity which exists in the PMT response to external signals to be measured. The results show that this testing approach provides a reliable and practical method for characterizing the PMT nonlinearity, enabling optimization of the operation conditions and improving the measurement accuracy of PMT by mitigating the nonlinearity. This study helps to advance the research and measurements in the related fields using a PMT.