A Measurement of Secondary Muon Angular Distributions

Project GRAND is an array of proportional wire chambers composed of 64 stations with each station containing eight proportional wire planes and a 50 mm steel plate. The proportional wire planes together with the steel absorber allow a measurement of the angle and identity of single muon tracks. Of the two data-taking triggers, one is for single tracks. Since the rate of single muon tracks at sea level above the muon energy threshold of the experiment (0.1 GeV) is substantial, good statistics are available by accumulating several years of data. A map in sidereal right ascension and declination is obtained as well as one in a sun-centered coordinate system in order to study the sidereal and solar effects separately.