The use of ion accelerators for purposes other than nuclear l physics research has expanded to the point where lother uses are now the most typical. The point has been reached where there are as many ion accelerators in industry, as in universities; and the bulk of new accelerator purchases appears to be for applied pur­ poses. We mention this as introduction to a tribute to an earlier book: IINew Uses of Low Energy Accelerators" (1968). The authors of tnis book were almost all nuclear physicists. This book ad­ dressed itself to new uses other than nuclear research. And in great part because of the widespread seminal influence of this book, many of the new uses discussed became mature fields of re­ search with their own conferences and publications. We have attempted in this book to both update with topics not included in the first book, and to present in a more tutorial and detailed manner the topics discussed. This book is in many ways a joint book. All chapters were the result of considerable collaboration between the authors. We hope that, above all, we have written with clarity. We welcome comments and questions from any reader. James F. Ziegler IBM-Research v CONTENTS CHAPTER 1. Ion-Excited X-Ray Analysis of Environmental Samples Thomas A. Cahill I. Introduction .......•......