William A. Barletta Department of Physics, MIT, Cambridge, MA

Engines of Discovery: A Century of Particle Accelerators by Andrew Sessler and Edmund Wilson, World Scientific, (2007) (212pp, $54 hardback, $31 paperback, ISBN 8 978-981-270-070-4)

In founding Nuclear Instruments and Methods, the late Kai Siegbahn gave voice to his understanding that instruments and techniques are often of decisive importance to advancing scientific understanding. Indeed Kai’s Nobel Prize winning discovery and development of Electron Spectroscopy Chemical Analysis (ESCA) is an archetype of the crucial role that instruments play in advancing the frontiers of scientific understanding.

Fifty years after the founding of NIM, most readers of this journal are knowledgeable about at least some dimensions of the vast contribution that particle accelerators have made to frontier research in physics, chemistry and now biological sciences. Indeed many think of particle accelerators as the quintessential characteristic of “big science.” Yet as an academic discipline accelerator science and technology is hardly present in the physics and engineering curricula of major research universities, especially in the United States. Thus it is hardly surprising that the intellectual enterprise of accelerator building and its most illustrious practitioners remains obscure to those outside the profession. It is as if – as Kai noted in 1957 – descriptions of these instruments and methods were “frequently hidden in the form of rather sketchy introductions to various papers.”

Fortunately, the technical literature of particle accelerators is now rich and expanding, yet the dimensions of the human enterprise remain too little known. To remedy this deficiency, Andrew Sessler and Edmund Wilson, two illustrious participants in the advance of accelerator-based science have written what is almost the “coffee-table book” of accelerators. Written in language that is easily accessible to the layman, their book is lavishly illustrated with photographs of ground-breaking machines from the dawn of the accelerator age to the present. Episodes in historical development are grouped in nearly independent chapters according to the type of accelerator – linac, cyclotron, synchrotron, collider, etc. Each chapter is an intellectual adventure story with its own heroes – described in sidebars – its own dramas, its own competitions, and its own missteps. Mercifully, the authors have not included a plot of machine energy versus time, the so-called Livingston chart that has too often been used as a publicity slogan. Instead, they have identified successive hurdles of physical phenomena that have limited the energy reach of accelerators and go on to describe the imaginative physical and engineering insights leading to new classes of machines. Individual achievement alone does not account for the dramatic progress in accelerator based science.

The research laboratories that have lent such fertile ground on which these heroes and their colleagues have built engines of discovery also receive well-deserved attention from Sessler and Wilson. These laboratories have been the home to the grand style of accelerator building that has been typified by machines of ever higher energy, ever higher intensity, and often ever larger size. These are the instruments – along with large detectors – that have generated the Nobel prizes of accelerator-based science and have been essential to our understanding of the sub-nuclear world. The authors do an admirable job of conveying the intellectual ferment and excitement that have made these institutions such attractive places for scientists and engineers to spend their careers.

Despite the book’s name, the authors have not neglected to describe the applications of accelerators that have made these instruments engines of commerce and engines of well being. Small accelerators abound for industrial uses that are essential to modern information and communication technologies that include ion implanters, non-destructive test and inspection equipment, and sterilization and disinfestation devices. Indeed these devices constitute the overwhelming majority of the world’s 14,000 accelerators. Examples of such commercial uses of various types of machines are woven throughout the text. Entire chapters are devoted to synchrotron light sources and to describing the electron and hadron accelerators used for cancer therapy. For those in the field, the biographical sidebars may be the most intriguing and delightful aspect of this book, even as they are likely to generate the most numerous (minor) nit6 picks. Why was x included, but not y? Why was Bruno Touschek described as an Austrian physicist instead of an Austro-Italian physicist, when others have been described by the nationality of their adopted country?