Building the H Bomb: A Personal History,
The development of nuclear weapons remains one of the most dramatic events of 20th-century science and technology. With the publication of Ken Ford’s Building the H Bomb: A Personal History, readers interested in the story have an engaging new firsthand account to add to their collections. This work is really three books in one: a history of the development of the first hydrogen bomb in its political context; a mini-textbook on nuclear physics and nuclear weapons; and a memoir of the author’s experiences as a graduate student working in the H-bomb program.
In a brief introductory note, Ford shares that the US Department of Energy had reviewed the document prior to publication, claimed that some passages contain government secrets, and asked him to redact them—he did not. From my reading, Ford relates nothing that cannot be gleaned from numerous online sources or existing histories such as Richard Rhodes’s monumental Dark Sun: The Making of the Hydrogen Bomb (Simon & Schuster, 1995). Ford’s book is not a primer on how to build a hydrogen bomb.
Ford entered Princeton University’s graduate program in physics in the fall of 1948 and studied under John Wheeler. After finishing his qualifying exam in the spring of 1950, Ford was courted by Wheeler and Edward Teller to join them in Los Alamos to work on the H-bomb project. The senior scientists were responding to President Harry S. Truman’s directive to the Atomic Energy Commission (AEC) to continue work on all forms of atomic weapons, “including the hydrogen or so-called super bomb.” Ford arrived at Los Alamos in June 1950; his work involved calculations of the “thermonuclear burning” characteristics of putative bomb designs.
At the time, though, the H-bomb program was at an impasse. Calculations then were predicated on what would come to be called the “classical super” design, in which researchers anticipated that the temperature of the fusion fuel would have to greatly exceed that of the radiation in the explosion. Otherwise, too much energy would be lost from the fuel to the radiation field. But those calculations indicated that the fuel would cool too rapidly to maintain fusion reactions.
The breakthrough idea emerged early the following year when Stanislaw Ulam realized that a fuel–radiation temperature equilibrium could be tolerated if the fuel were compressed. Teller modified the idea to use radiation from a triggering fission weapon—not mechanical force—to achieve the compression; the configuration became known as the Teller–Ulam design. Debate continues as to how priority for the concept should be assigned between Ulam and Teller. Ford analyzes the various claims and chronicles Teller’s evolving statements, which often denied Ulam any significant contribution. Whatever the circumstances of its genesis, the Teller–Ulam concept took center stage at Los Alamos.
In late 1950 Wheeler began relocating the computational effort—what became Project Matterhorn—to Princeton, and Ford moved back East. He programmed calculations of the propagation of the “thermonuclear flame” through cylinders of imploded deuterium and ran them on various card-fed and plug-board computers. The physics that was wrung out of machines having far less memory than a flash drive and operating at speeds less than a thousandth of that of today’s desktop computers is a testimony to the ingenuity and perseverance of those involved.
Ford’s calculations indicated that the Teller–Ulam design was feasible, and it was subsequently endorsed at a June 1951 meeting of the AEC’s General Advisory Committee. Ford recalls passing Wheeler handmade graphs through the window of the meeting room following an all-night work session. At Los Alamos, Richard Garwin was already busy designing the Ivy Mike device, which would be detonated at Enewetak atoll on 1 November 1952 (local time); it was the first full-scale test of the H bomb that used the Teller–Ulam design. Ford’s predicted yield was 7 megatons; Garwin’s design achieved 10.4 megatons, and Ford felt lucky to have calculated a number in the correct ballpark.
In the epilogue, Ford relates how he sincerely felt that having the H bomb in American hands would contribute to maintaining peace, but that view changed during the Vietnam War. In 1968 he declared at a meeting of Los Alamos scientists opposed to the war that he had decided to do no further weapons or classified work, a step he regarded as personally daring but satisfying.
Ford’s book is a valuable resource for anyone interested in the history of the H bomb and its role in the Cold War, and in how that work affected the life and career of an individual involved.
Cameron Reed is the Charles A. Dana Professor of Physics at Alma College in Alma, Michigan, and author of The History and Science of the Manhattan Project (Springer, 2013).