SPICE Model of Photomultiplier Tube Under Different Bias Conditions

A generic SPICE model of a photomultiplier tube (PMT) is proposed and demonstrated experimentally. The nonlinearity of the PMT was reproduced by applying the manufacturer gain curve. The modeling concept is based on behavioral-dependent sources that emulate the electron multiplication process between interstage dynodes of the PMT. The static condition of the PMT directly influences performance in terms of gain stability, linearity, dynamic range, transient response, power consumption, heat dissipation, and so on. The model can be used to calculate or simulate the values of the PMT variables while connected to different voltage divider circuits. The proposed model was found to faithfully reproduce the experimental static electrical behavior of the R7400U PMT biased by different voltage divider circuits. The PMT model was tested under varying bias conditions at no light and under 400-μA anode current.