Tests of a range-compensated PMT base

The base design used in the tests is similar to one reported by Allen and Evans (1972). In this base the potential of alternate dynodes is varied with time so as to produce a gain which increases with the square of the time after triggering. Attention is given to modulator design, performance tests, the tube's output for a constant light source, the use of an exponential light source, and the effect of defocusing. The test results show that a range-corrected output with less than 10% error between 1.5 and 40 microsec can easily be obtained with the considered design. The accuracy could probably be improved to 6% with more careful adjustment.