William E. Stephens

Nuclear Fission and Atomic Energy William E. Stephens

NUCLEAR FISSION and ATOMIC ENERGY by WILLIAM E. STEPHENS. Contents include: Foreword vii Editors Preface ix Chapter 1. Discovery of Fission 1 2. Production of Fission 6 3. Fission Fragments 16 4. Fission Products 22 5. Secondary Neutrons 43 6. Heavy Nuclei 50 7. Theory of Fission 67 8. Dynamics of Fission 92 9. Early Work on Chain Reactions 117 10. Slow Neutron Chain Reactions Piles 133 11. Fast Neutron Chain Reaction 171 12. Separation of Isotopes 181 13. Chemical Separation Methods Isolation of Plutonium 222 14. Potentialities of Fission Techniques 234 Bibliography ... 259 Author Index 281 Subject Index 287. FOREWORD: FREE and unrestricted research in nuclear physics ceased abruptly in 1941. Activity in the field went underground and certain aspects were the subject of intense study and investigation in secret under the forced draft of military urgency and unlimited support. It emerged on August 6, 1945, with the most destructive explosion that has ever been produced by man. The same dra matic event answered affirmatively the outstanding question which had engaged nuclear physicists previously Is a self-sustaining nu clear chain reaction possible The successful culmination of the work of the Manhattan District in the explosion of the bombs over Japan punctuated the end of the war and announced the scientific fact that nuclear chain reactions could be brought about. With the cessation of hostilities nuclear physicists have re turned from a wide variety of war research assignments to this, their chosen field. The obvious first step in resuming programs of fundamental research has been a review of the literature and a taking of scientific stock in the light of available information. At the University of Pennsylvania a series of seminars was conducted by Dr. Stephens and the staff of the Department of Physics resi dent in the autumn of 1945, for the purpose of reviewing all freely available information and reorienting the interests of the research group. The extensive examination of all the pertinent literature at their disposal and the careful study of its implications in the light of present common scientific knowledge has been of great value in the planning of a research program at the University of Pennsylvania. It is in the hope that the efforts of this group may serve a much broader purpose in assisting their scientific col leagues elsewhere to resume their research programs or enable them to enter their field of fundamental investigation that these seminar notes have been edited for publication. Unfortunately this book perforce marks a departure from traditional scientific publications, a departure which it is hoped is only a temporary result of abnormal post-war conditions. The authors of this book, in common with authors of reviews in other branches of physical science, have dealt only with information that is available to all. But unlike authors of pre-war treatises they are aware that there exists a body of pertinent knowledge inaccess ible to them. To avoid any possible imputation of inadvertent breach of security they have been at pains not to discuss these topics with any persons in possession of classified knowledge con cerning them. Though a more complete book on the subject might be written by men who have participated in the atomic bomb proj ect, such persons are at present legally precluded from such an undertaking. The very ignorance of the authors of this book thus enables them to contribute their special training to the writing of it as a contribution to the advancement of knowledge in the best scientific tradition...