An experimental test of position resolution of a lead glass array

Abstract We report on an experiment to examine the use of lead glass Cherenkov counters in a hodoscope to determine the trajectory of incident shower particles, i.e. electrons, positrons, or photons. This tests the accuracy with which an incident positron can be located using only an array of lead glass counters. Twelve lead glass counters were used in each of three counter configurations, at 1.5, 3.1 and 4.2 GeV. For each configuration, the axis of the electromagnetic shower was calculated from the digitized lead glass counter pulse heights, and compared to the trajectory of the incident positron, which was separately measured with spark chambers. For one of the configurations, the one-dimensional discrepancy between the positron trajectory and the calculated shower axis was less than 1.1 cm (fwhm) at 1.5 GeV and 3.1 GeV.