Cosmic Rays HARVARD UNIVERSITY PRESS Cambridge, Massachusetts, and London, England 1989 Cosmic Rays Michael W. Friedlander Copyright © 1989 by the President and Fellows of Harvard College All rights reserved Printed in the United States of America 10 98765432 1 This book is printed on acid-free paper, and its binding materials have been chosen for strength and durability. Library of Congress Cataloging-in-Publication Data Friedlander, Michael W. Cosmic rays. Bibliography: p. Includes index. 1. Cosmic rays. I. Title. QC485.F75 1989 539.7'223 88-24371 ISBN 0-674-17458-5 (ilk. paper) Contents 1 The Early Days 1 2 Identifying Cosmic Rays 11 3 The Earth's Magnetic Influence 26 4 Particles from the Sun 41 5 Cosmic Rays in the Galaxy 53 6 The Energy Spectrum 75 7 Nuclear Clues 87 8 The Origin of Cosmic Rays 99 9 Cosmic Rays with Little or No Mass 111 10 The Subnuclear World 125 11 Footprints and Souvenirs 138 Works Cited 153 Bibliographical Note 155 Index 157 Cosmic Rays Acknowledgments It is a pleasure to acknowledge the help that I have received, both directly and indirectly, in the preparation of this book. More colleagues than I can list in the cosmic ray community have provided stimulation and friendship over many years. Many of them responded generously to my request for photo- graphs. The manuscript has benefited greatly from the careful scrutiny it received from several reviewers, as well as from the helpful suggestions of Howard Boyer and the excellent editing of Mary Ellen Geer at Harvard University Press. To all of these individuals, and especially to my family for their unfailing inter- est and support, I am deeply grateful.