Energy spectrum of muons from their knock-on electrons

Abstract

The energy spectrum of muons producing knock-on electrons in medium- and low-Z elements has been determined. The energy of a muon can be determined from the energy it transfers to a knock-on electron and the angle which the knock-on electron makes with the direction of incidence of the primary muon. The energies of 289 and 271 incident muons producing knock-on electrons of energies greater than 25 MeV in carbon and aluminium and of 273 muons producing electrons of energy greater than 60 MeV in copper plates placed inside a counter-controlled multiplate cloud chamber, have been determined. The spectrum of muons at this place is then obtained after taking into account the variation of knock-on cross-section with muon energy and integrating this cross-section over electron energy intervals (ɛmin to ∞) considered in this experiment. The spectra of muons thus obtained compare favourably with the corresponding sea-level spectra as obtained by the Durham magnetic spectrograph.