Inefficiency and Other Sources of Error in Cosmic-Ray Measurements with Self-Quenching Counters

The errors in coincidence measurements with self-quenching counters, due to inefficiency inherent in the counters and due to apparent inefficiency arising from showers and scattering, have been measured. The inefficiency inherent in the counters has been found to be almost entirely due to the dead time. The dead time, for the counters investigated and with the recording circuit employed, was 4×${10}^{-4\mathrm{}}$ second. This gives rise to an inefficiency of 0.2 percent in counters with a normal counting rate of 300 per minute. The apparent inefficiency of the counters and the error in coincidence measurements, for most of the experimental arrangements used were found to be almost entirely due to showers. From the data presented below, we estimate that near sea level, with the counter telescope in the vertical direction and with 35 cm between the extreme counters, the coincidences due to side showers were about 15 percent of the normal coincidence rate when two counters were in coincidence, 7 percent when three counters were in coincidence, and 3 or 4 percent when the telescope contained five counters in coincidence. These percentages increased by a factor of 2 when the apparatus was taken from 259- to 4300-m elevation.