Mars: the interaction cross-section of positive and negative muons

The Durham spectrograph MARS, has "been used to study the electromagnetic interactions of cosmic ray muons in iron in the range 6 - 200 GeV. Single, electrons and electron bursts of various sizes from the knock-on, direct pair production and bremsstrahlung processes were observed. The possible asymmetry in the interaction of positive and negative muons as a function of muon energy and energy transfer was investigated. Also investigated was the absolute value of the interaction probability for single electrons and electron bursts of different sizes as a function of muon energy. Experimental burst spectra for burst sizes up to 80 particles were established and compared with prediction. The results on the interaction asymmetry suggest no asymmetry for single electron production and give an asymmetry value of 1.08 ± 0.055 for production of two or more secondaries. The results on the absolute values of the interaction probability are in good agreement with expectation. Thus, it is concluded that there is satisfactory agreement with theory.