Electromagnetic interactions of cosmic ray muons in iron

Electromagnetic interactions of cosmic ray muons have been studied in a spectrometer-calorimeter system. The calorimeter was a sampling total absorption counter (STAC) of removable iron plates (14 g/cm2 each) and optical current limited spark chambers. A thin plate version (each plate 8 was designed to investigate the knock-on process and the direct pair production in the range of low energy transfer. For energies below 2 GeV the better energy resolution of this version of the calorimeter was established by a calibration measurement at the DESY accelerator. The results of the interaction experiment are consistent with the theoretical predictions. As a function of the muon energy the probability of secondaries produced by the muon are presented. (author)