Investigation of Cathode Uniformity and Transit Time Spread of Multiplier Phototubes

The investigation of photocathode uniformity using the flying spot scanner technique is enhanced by the addition of a single-line-selector oscilloscope. This instrument permits a detailed study of any portion of the photocathode surface. The results obtained are of assistance in evaluating cathode uniformity per se as well as the efficiency of electron collection. Transit time spread measurements are determined by using a coincident method of detection employing output signals of opposite polarity. Measurements of transit-time spread are made by comparison with a variable light path used as a time delay.