Two blogs ago I made you read about the creation of the Atomic Energy Commission, the AEC. Almost as a footnote, I mentioned that the act created the General Advisory Committee, the GAC, and Oppenheimer was appointed to be its first chairman. The GAC’s job was to give scientific advice to the commissioners of the AEC. The AEC’s first chairman was a Harvard lawyer named David Lilienthal, who had been co-director of the Tennessee Valley Authority during the Great Depression. Lilienthal and Oppenheimer were both vehement opponents to developing the Super. So you see, we have a readymade story here with a hero, Lawrence, who must overcome obstacles created by villains.
Lawrence’s zeal to overcome challenges would eventually lead him to the town of Livermore, California. Here are some highlights from my upcoming book, From Berkeley to Berlin:
Oppenheimer, still chairman of the AEC’s GAC, and David Lilienthal, the AEC Chairman, shared a common aversion to thermonuclear research. Lilienthal felt he needed more technical information to respond to mounting inquiries from government officials, so he bade Oppenheimer to call a special meeting of the GAC to assess the Super. Gathering quickly, the GAC assembled on October 28, 1949, in five sessions over the course of three days.
On the second day, the GAC meeting was opened to AEC commissioners and senior military officers from the Pentagon. They asked members of the GAC how America should respond to the Soviet A-test. Oppenheimer’s consistent argument was for the country to rely on its atomic bombs for strategic defense rather than to start a new program for a bigger weapon. Part II of the report stated:
The General Advisory Committee has considered at great length the question of whether to pursue with high priority the development of the super bomb. No member of the Committee was willing to endorse this proposal. The predominant message of the report said it was immoral to pursue such a weapon.
The recommendation of the GAC to stop the Super made Teller more adamant to push the program. Teller traveled east and continued to recruit physicists to join his group. He asked Fermi to take over the Super project, but Fermi declined and instead volunteered to come to Los Alamos part-time as a consultant.
Teller telephoned John Wheeler, an American physicist he had met while at Niels Bohr’s Institute for Theoretical Physics in Copenhagen, and asked for his help. (This is the same Wheeler who had co-authored the nuclear fission article with Niels Bohr.) Wheeler was in Europe, on sabbatical, to conduct research in France and to write a physics paper on the atomic nucleus with Bohr.
While in Copenhagen, working with Bohr on their paper, Wheeler told his mentor about his indecision. As they discussed it at breakfast, Bohr said to Wheeler, “Do you imagine for one moment that Europe would now be free of Soviet control if it were not for the Western atomic bomb?” That settled it for Wheeler, and he moved with his family to Los Alamos.
Wheeler was one of America’s greatest physicists of the 20th century. A pioneer with Bohr on the theory of the atomic nucleus, he had been Richard Feynman’s thesis advisor and helped lead Feynman to win a Nobel Prize. Later in his career, Wheeler switched physics fields and wrote a classic work on general relativity that became one of America’s more popular physics textbooks. He coined the term “black hole” to describe a star so massive even light could not escape it.
Teller continued to recruit. He went to Cornell University to enlist another physicist friend, Hans Bethe, and thought he was succeeding. As the two discussed the work, Bethe received a call from Oppenheimer, who asked that he come to Princeton to meet with him. A few days later, Bethe called Teller to say he was not joining his team to develop the Super.
While still on the East Coast, Teller scheduled a meeting with Senator McMahon. When Teller reached the senator’s office the next day, they discussed the GAC report on the Super. McMahon was furious; he felt if Congress adopted the GAC’s recommendations, it would lead to a catastrophic situation with the Soviets in sole possession of a thermonuclear weapon. He wondered what could be done and discussed the merits of moving the Super program to a new laboratory where competition might spur LASL to greater effort.
McMahon urged President Truman to order the AEC to develop a thermonuclear weapon. He said if the Russians produced the hydrogen bomb first, the results would be catastrophic, whereas if the Americans produced it first, there was at least a chance of protecting the country through deterrence.
Truman wanted more opinions, so in December 1949, he asked a subcommittee of his National Security Council to determine whether or not to develop the Super. The subcommittee members were Secretary of Defense Louis Johnson, Secretary of State Dean Acheson, and AEC Chairman David Lilienthal. Lilienthal alone backed the GAC report rejecting development of the Super, while Johnson recommended stepping up a thermonuclear program. Acheson said he didn’t accept the GAC logic calling for “maintenance of ignorance or the reliance on perpetual goodwill,” which he deemed an untenable policy, and he sided with Johnson.
Truman accepted the advice of his two senior cabinet members and made his decision on January 31, 1950:
It is part of my responsibility as Commander-in-Chief of the Armed Forces to see to it that our country is able to defend itself against any possible aggressor. Accordingly, I have directed the Atomic Energy Commission to continue its work on all forms of atomic weapons including the so-called hydrogen or super bomb.
Among those who opposed Truman’s decision, Oppenheimer and Lilienthal were the most vocal; Bethe expressed his views in a letter to the editor in the April 1950 issue of Scientific American.Those like Wheeler, who disagreed, were in the minority and risked social stigma for their views; they were often snubbed at professional gatherings. Wheeler remained adamant in his view that work on the Super was important and had to be done. He understood the revulsion felt by some of the Manhattan Project physicists over the effects of their work in Hiroshima and Nagasaki, but he noted those who had closely experienced the killing in the war did not share those feelings.
Wheeler’s brother Joe, a driven young man who had earned a PhD in history, served in the Army in World War II, and fought in Italy. He was smart enough to realize his older brother was involved with making a nuclear weapon, and he saw it as something badly needed. In a postcard written to John a few months before he was killed in combat, Joe wrote, “Hurry up.”
Wheeler later revealed his feelings if the government had not dithered for months after President Roosevelt had ordered a start to an atomic program, his brother might not have died. Wheeler had no doubt the atomic bomb had stopped the war in its tracks and therefore saved countless American and Japanese lives. He could see no difference with the situation before World War II of a threat from Nazism, and the situation then facing America with the threat from Communism. In his mind, the best way to avoid a war with the Soviet Union was to have a weapon that could deter it.
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Remembering Ulam’s warning during his visit to Los Alamos that the Super program needed tritium, Lawrence committed himself to finding a way to produce it. Since AEC reactors were dedicated to producing plutonium, which was in short supply, Lawrence did not want to slow down plutonium production for the sake of tritium production. The plutonium production reactors were moderated with graphite, like Fermi’s nuclear pile; Lawrence thought he could avoid taxing AEC reactors by proposing to build a reactor moderated with heavy water, which could produce tritium efficiently. Alvarez accepted responsibility to lead the effort.
Alvarez assembled cost estimates while Lawrence selected a site for the reactor in Suisun Bay, northeast of Berkeley. With his proposal prepared, Alvarez discussed it with AEC commissioners and the GAC. When he met with Oppenheimer, he became aware how much the GAC Chairman opposed the hydrogen bomb. Alvarez realized he could not dissuade Oppenheimer, and if Oppenheimer opposed building the hydrogen bomb, he would certainly oppose building a reactor to furnish tritium for it. Alvarez returned to Berkeley and dropped the proposal.
Lawrence wasn’t so easily dissuaded and came up with an alternate plan. He ordered calculations done on the feasibility of using an accelerator to make tritium.He tasked one of his Rad Lab physicists who had returned from the Y-12 Plant, Herb York, to measure the efficiency of producing neutrons in that way. York was assigned a newly arrived 21-year old physicist from Columbia University named Harold Brown to help him. Tall and slim, Brown looked like he had nothing in common with the shorter and stockier York. In fact, as we will see, they complemented each other greatly as they set about designing accelerator targets and measuring results.
The new accelerator would require a vacuum chamber 60-feet in diameter! Lawrence tagged Johnny Foster, who had returned from service in the Army Air Corps in Italy and who was a member of Alvarez’ research group at the Rad Lab, to design an ion pump vacuum system to evacuate the cavernous volumes.
Lawrence took the MTA concept to Washington, DC, and over the objections of Isidor Rabi, a member of the GAC, he presented his ideas to Kenneth Pitzer, the Director of Research at the AEC. In February 1950, Pitzer approved the project and directed construction to begin. Where to locate the MTA? The project was too large for the Berkeley campus.Lawrence asked Washington for a list of possible sites. Most were abandoned military bases. One at Livermore, California, a square mile in area, offered mile-long runways, barracks buildings, a gymnasium, and a huge indoor swimming pool. As soon as Lawrence and Alvarez saw it, Lawrence said, “Well, Luis, this is it.”
The MTA was a prototype machine; a full-sized plant would be a 1,000-foot long accelerator built at Weldon Spring, Missouri. It never came to be. The special nuclear materials the MTA was supposed to produce had become more abundant, as uranium ore, once scarce, had been discovered by prospectors lured to its high value. More plutonium had been produced, making it easier to share reactors to produce tritium. By the time the MTA came online, the critical shortage of tritium and plutonium motivating its creation was gone.
Despite the morass of technical difficulties, Lawrence was determined to keep the Super project going. With the newly acquired campus in Livermore, he had room to conduct more research, and he sent Alvarez to see Teller at Los Alamos to find out what the Rad Lab could do to help. Teller said he could use help with upcoming nuclear tests, so Alvarez assigned two Rad Lab physicists, Herb York and Hugh Bradner, to lead a project to lend support to Los Alamos.
The George event was part of Operation Greenhouse, a series of four nuclear tests in April and May 1951 at the Pacific Proving Grounds—an area in the South Pacific that included the Marshall Islands. Two atolls of the Marshalls, Bikini and Eniwetok, were epicenters for American testing. The last two tests in Greenhouse, named George and Item, featured events in which Teller had predicted thermonuclear reactions.
So, York and Bradner organized a group of physicists to build an experiment to detect thermonuclear reactions on the George event, and they called themselves the “Measurements Group.” They needed a lot of space, more than was available at the Rad Lab, so they occupied a barracks adjacent to the MTA site in Livermore, and called themselves Project Whitney. With construction of the diagnostic equipment underway, York left for the South Pacific and prepared for the George event.
At Eniwetok, Teller arrived one evening and met with York in a Quonset hut. Teller went to a blackboard on the wall and drew a design for a thermonuclear device based on a paper he had written with Stan Ulam the previous month. York saw how it worked and thought about how to design such a weapon, but those ideas would have to surface later. After two months of hard work, the Measurements Group arrived at Eniwetok and installed sensors in time for the George event, scheduled to occur on May 8, 1951. This, their first experience with a nuclear test, was a success, for they were able to detect thermonuclear reactions. They had verified Teller’s idea that an atomic blast could ignite nuclear fusion.
Brimming over with joy over the successful experiment, York went back to the Rad Lab and Lawrence secured a position for him to begin a new career teaching physics at the University of California in Berkeley. One of his first assignments was an introductory physics course, and he was assigned a graduate student, Mike May, to be his teaching assistant. After seven years at the Rad Lab, he was at last feeling secure about his life’s work and looking forward to a quiet and fruitful career as a college professor.