AUTOMATIC PHOTOMULTIPLIER TUBE VOLTAGE CONTROLLER

摘要

The repeating chain of pulses of a GeMSAEC analytical photometer is referenced to a constant amplitude water blank pulse that is sampled with each revolution of the rotor. A feedback circuit samples the amplitude of the water blank cuvet signal by means of a fast-acting solid state switch. It assures that the water blank signal amplitude remains constant by controlling the photomultiplier tube high voltage supply following comparison of the water blank transmission signal with a very well regulated reference voltage. Thus, in the event of photomultiplier gain change or power supply drift during operation, automatic restoration of the photometer data transmission signals to their correct values will occur.