Light intensity meter uses either rate of anode pulses from photo-electron multiplier or amplitude of direct current from photocathode, depending on light intensity

摘要

The intensity meter has a photo-multiplier (15) with a photocathode (16) and a dynode system (D). Depending on the intensity of the light to be measured, either the rate of anode pulses from the photo-electron multiplier (15) or the amplitude of the direct current from the photocathode or both are used to obtain a measured value. The amplitude of the dark current including the leakage current from the measuring apparatus is determined, stored and used to correct measured values, to enable a cathode photo current (Ik photo) to be determined whose leakage current has been compensated. An Independent claim is included for a light intensity meter.