High energy muons in large extensive air showers

Abstract

A magnet spectrograph in the centre of a large array of diff-used-light water Čerenkev detectors has been used to measure the momentum spectrum and lateral distribution of muons in large extensive air showers. The data cover the ranges: 1-100 GeV/c in muon momentum, 10-700 metres in core distance, and 10(^5)-10(^8) particles in shower size. The spectra are presented in the form of integral and differential densities as functions of muon momentum and EAS core distance. Details are given of the construction of the spectrograph and EAS arrays, the collection and treatment of the data, and the derivation of the momentum spectra and the analysis of the results. Experimental results are also presented on the charge ratio of EAS muons, and an interpretation is offered for the bursts, observed in the visual detectors, which are produced in the spectrograph iron. Wherever possible, comparison is made between the results of the experiment and the observations of other workers. Previous theoretical models of EAS muori production have been critically examined and it is shown that the assumptions on which they are based are not valid for all EAS muons. In particular, the density of muons possessing large momenta far from the shower core is sensitive to the assumptions made about the first interaction of the primary cosmic ray. A careful analysis of the problem shows that such muons provide a means of estimating the mass of primary cosmic rays in the EAS energy region.