The story of the development of nuclear weapons continues to fascinate physicists and historians alike. Few of the principals involved in the first years of this work now remain with us, so new firsthand accounts are rare. This very readable book by Ken Ford is a welcome and worthy addition to the genre.
The 16 brief chapters of this book tell three intertwined stories. Readers whose focus is physics will find it a mini-textbook on nuclear physics summarizing discoveries from the discovery of radioactivity through to the discovery of fission and the physics of both fission and fusion-based nuclear weapons. [Like many others, Ford attributes the discovery of radioactivity to Henri Becquerel, but his claim to this discovery has been disputed; see, for example, Tony Rothman's Everything's Relative: And Other Fables from Science and Technology (Wiley, 2008)]. Historians and students of science policy will enjoy the description of the development of the first hydrogen bomb, the personalities involved in that program, the political environment within which the work took place, and the chilling effects of Cold-War loyalty oaths and Congressional investigations on the scientific community. But above all this book is a personal memoir of Ford's work with the H-bomb program for a little over two years (1950–1952) when he was a graduate student; any reader who wonders what the day-to-day experience of working on such a monumental project was like should read this book.
In a brief note at the start of the book, Ford comments that the Department of Energy claims that it contains secrets and that he was asked to redact some passages prior to publication. However, readers familiar with the physics involved will find that he relates nothing that cannot be gleaned from standard texts, online sources, or existing histories such as Richard Rhodes' Dark Sun (Simon and Schuster, 1995). Ford's book is not a manual on how to design or build a hydrogen bomb.
After graduating from Harvard, Ford entered Princeton's graduate program in physics in the fall of 1948 and became a student of John Wheeler. This was the beginning of what would become a lifelong friendship between the two men and their families. Wheeler had just begun a sabbatical leave in Europe for the 1949–1950 academic year when the Soviet Union exploded its first atomic bomb in August 1949, and Henry Smyth and Edward Teller began urging him to cut short his leave to go to Los Alamos to work on developing a hydrogen bomb. A few months later Wheeler decided to do so, spurred by President Truman's January 1950 directive to the Atomic Energy Commission “to continue its work on all forms of atomic weapons, including the so-called hydrogen or super bomb.” Ford finished his qualifying exam in the spring of that year and soon found himself being courted by Wheeler and Teller to join them at Los Alamos. Against the concern of the department chair that he might never return to finish his graduate studies, Ford, motivated by the thought that it would be better if the United States acquired an H-bomb before the Soviet Union, opted to make the move. He was on his way to Los Alamos in June 1950 when the Korean War broke out, which further deepened international tensions. As a 24-year-old junior member of the H-bomb design group, Ford was assigned to work on calculations of the “thermonuclear burning” characteristics of putative bomb designs, and he was soon rubbing elbows with heavyweights such as Teller, Stanislaw Ulam, Hans Bethe, Carson Mark, Enrico Fermi, and John von Neumann.
In mid-1950, the H-bomb program appeared to be at a fundamental impasse. Designs were being predicated on what would come to be called the “classical super” configuration, wherein it was anticipated that the temperature of the fusion fuel would have to greatly exceed that of the radiation in the explosion environment in order to minimize energy loss from the fuel to the radiation field. But calculations indicated that the fuel would radiate away energy at such a rate that it would cool and be unable to maintain fusion reactions. The key breakthrough emerged around February of 1951 when Ulam realized that a fuel/radiation temperature equilibrium could be tolerated if the fuel were compressed. Edward Teller, who had previously thought that compression would not help, seized on the idea and modified it to use radiation from a triggering fission weapon to achieve the compression (as opposed to mechanical forces), an arrangement which became known as the Teller-Ulam design.
Debate still continues as to how priority for the Teller-Ulam concept should be assigned between these two individuals. In his first two chapters, Ford analyzes the various claims and chronicles the evolving statements made by Teller, who often perversely factored Ulam out of any significant contribution while factoring others in and crediting himself with conceiving the idea in advance of Ulam. Ford relates that Hans Bethe felt that in early 1951 Teller “… obviously did not know how to save the thermonuclear program.” Ford's own assessment is that Ulam did have a thermonuclear weapon in mind but may not have understood the benefit of radiation as a compression mechanism and that Teller's thinking on radiation implosion had not gelled before a crucial meeting with Ulam. Ford touches only briefly on how Robert Oppenheimer's early opposition to the H-bomb would eventually be used against him in his 1954 security hearing, but here a much more serious Teller-focused issue was in play. Oppenheimer had long advocated the development of tactical-scale fission bombs that could conceivably be applied to a much broader range of military applications than the multi-megaton devices that so captivated Teller, but the latter had no credible missions. An analysis of which man had a more sensible view of ensuring nuclear-based national security would make for an interesting project in its own right. Tragically, both men suffered enormous personal damage as a result of the hearings and the government lost the benefit of Oppenheimer's years of experience.
A few months before the Teller-Ulam concept emerged, Wheeler, in response to his wife's unhappiness with life at Los Alamos, proposed to relocate the computational effort at Princeton. This effort came to fruition a few months later as Project Matterhorn and Ford moved back East; such a quick, relatively low-bureaucracy adjustment would be inconceivable today. With access to various card-fed and plug-board computers he began programming coupled-differential-equation-based calculations of the energy release that would result from the propagation of fusion reactions through cylinders of imploded deuterium and the secondary fission reactions that could be induced. Readers of a certain age will have graduate-school memories of all-nighters spent hunched over a terminal or perhaps even at a keypunch machine. Ford's description of cathode-ray-tube five-kilobyte memory banks, coding in machine language, and translating teletyped hexadecimal output to real numbers to be recorded in manual spreadsheets and plotted by hand on graph paper made me feel utterly spoiled.
The physics that was extracted from simulations that could be run with less than a millionth of the memory of a modern flash drive and which operated at speeds less than a thousandth of that of a current desktop computer is a testimony to the ingenuity and perseverance of those involved not to mention the national-level importance attached to the work. The calculations indicated that the Teller-Ulam design looked feasible, and it was consequently endorsed at a June 1951 meeting of the Atomic Energy Commission's General Advisory Committee. Ford recalls passing Wheeler's hand-drawn graphs through the ground-floor window of the meeting room following an all-night work session and then going off in search of breakfast; Oppenheimer later famously characterized the Teller-Ulam design as “technically sweet.” At Los Alamos, Richard Garwin was already busy designing the Ivy Mike device, which would be detonated at Enewetak Atoll in the Pacific on November 1, 1952. Ford's final estimate for the predicted yield was 7 megatons; Garwin's design achieved 10.4, and Ford felt lucky to have predicted a value in the correct ballpark. News that the test was successful reached Los Alamos by way of a three-word telegram sent by Teller, who observed it's effects via a seismograph signal detected in Berkeley: “It's a boy.” Over 70% of the energy came from fission reactions induced in the uranium cylinder that housed the deuterium fusion fuel.
Project Matterhorn was wrapped up in 1953. Ford completed his thesis that same year and went on to a distinguished career of teaching, research (mostly in the area of nuclear structure), writing, and administration. In a thought-provoking Epilogue, he relates how he sincerely felt that having the H-bomb in American hands would contribute to maintaining peace, but this view changed during the Vietnam War. Increasingly perturbed by the conduct of the war, he declared at a 1968 meeting of Los Alamos scientists opposed to the war that he had decided to do no further weapons or classified work. This action had no practical consequence as he was not then involved in any classified work, but he felt that making a public announcement—a step he regarded as personally daring but satisfying—would make the decision more irrevocable. He now feels that the correct target number of nuclear weapons is zero.
My only very minor complaints with this book are that its many interesting but parenthetical comments tend to distract from the flow of the narrative and I would also have liked to have learned more about the rest of Ford's career. But the author of a memoir has the latitude to tell his story as he wishes, so this is really at the level of an idiosyncrasy. This book deserves to be read by anyone interested in the history of the H-bomb, its role in the Cold War, and how such work can affect the lives and careers of the individuals involved.
Cameron Reed is the Charles A. Dana Professor of Physics at Alma College. He served as the editor of the American Physical Society's “Physics & Society” newsletter from 2009–2013 and is currently Secretary-Treasurer of the APS's Forum on the History of Physics. His interests lie in the physics and history of nuclear weapons; his text “The History and Science of the Manhattan Project” was published by Springer in late 2013.