The muon component of extensive air showers

Abstract

This thesis describes the determination of various characteristics of the muon component of extensive air showers (EAS) using the magnet spectrograph situated at the British Universities joint air shower array at Haverah Park, near Harrogate. After an introduction concerning the relevance of muon studies to current problems in the studies of air showers (Chapter l), the air shower arrays and the magnet spectrograph are briefly described and a summary given of the analysis of the data from each (Chapters 2 and 5)-The lateral density distribution of muons of momentum above 1 GeV/c is determined (Chapter k) for use in the normalization of the measured momentum spectrum of muons. The dependence of the number of muons on shower size is found to be constant over a wide range of size. The momentum spectrum of muons in air showers is determined as a function of distance from the shower core. The variation of spectrum with shower size and zenith angle is also investigated. These measurements extend beyond previous experimental work (Chapter 5), and do not agree with theoretical predictions. All the features can be accounted for by a careful treatment of air showers initiated by primary particles of mass greater than ten (Chapter 6), provided the multiplicity of pions follows an E (^0.5) law for high energy. The average heights of origin of muons of various momenta are determined by two different methods. It is further shown that the muons originate at heights compatible with the modified model (Chapter 7). The implications of these observations are discussed in Chapter 8 and, finally, experiments are suggested which might confirm the proposed model.