by Gino Segrè
Fermi had not become a member of ALAS, nor did he join its later offshoot, the Federation of American Scientists, an organization designed to broaden the ALAS membership base to include those who had worked at Hanford, Oak Ridge, and the Met Lab. As for Fermi’s nonparticipation, Szilard commented, “The struggles of our times did not affect him very much, and he is no fighter.” On a more charitable note, Fermi’s stance was compatible with his extraordinary ability and predilection to compartmentalize physics, devoid of any distractions—political or otherwise. His devotion to science was unwavering, and probing its complexities was inevitable. As Fermi observed, “Whatever Nature has in store for mankind, unpleasant as it may be, men must accept, for ignorance is never better than knowledge.”
In an August 28, 1945, letter to his Italian colleague Amaldi, Fermi had portrayed his time at Los Alamos as “a labor of considerable scientific interest” and continued by saying that “having contributed to truncating a war threatening to go on for months or years has undoubtedly provided a certain satisfaction.” In the same letter he expressed his hopes that the bomb would have a positive impact on international relationships. Fermi’s tone, understated and dispassionate, was more than familiar to those who knew him.
34
GOODBYE, MR. FARMER
“It had been one of the most remarkable periods of our lives,” according to Laura Fermi. But it was time to move back to Chicago; the mission had been accomplished. Regrets about leaving were mixed with looking forward to getting back to a more normal life. Laura remembers departing from Los Alamos on New Year’s Eve, half an hour before the celebrated ball drop at Times Square ushered in 1946.
Suitcases packed, they brought with them Indian pottery and jewelry, paintings, weavings, and cacti, memory-laden souvenirs that would decorate their new Hyde Park home. After spending the night in Santa Fe and being driven to the small Lamy train station, they waited for the Chief to pull in. The squeal of its brakes broke the silence of the clear, cold morning. For Enrico, it felt odd to board without the presence of his bodyguard, Baudino, who had accompanied him any time he traveled outside the gates of Los Alamos. Mr. Farmer was no more. Approximately twenty-four hours later, the tired family of four disembarked in Chicago’s busy Union Station, the skylight of its great hall arching high above marble floors.
They all knew the move would be an adjustment. Judd (formerly Giulio) had disliked Los Alamos, in part because it had meant yet another upheaval. There had been a plethora of moves for the youngster: first from Italy to New York City, then to New Jersey, Chicago, and Los Alamos, now once again back to Chicago. Nella seemed to adapt more readily than he to the many changes. Life again would be different for her and her brother. A certain freedom in what was arguably America’s most secure and crime-free town would be replaced by the watchfulness of living in a city neighborhood where muggings were not uncommon. For Laura and Enrico it meant that dear friends would scatter and the esprit de corps that had characterized their lives would dissipate.
In a step that was both perceptive and brilliant, the University of Chicago had developed a scheme that would maintain the momentum of scientific wonder and craft a structure enticing the likes of Fermi. In mid-July 1945, the university’s vice president, its dean of physical sciences, and Harold Urey, who was associated with the Met Lab’s program of isotope separation, traveled from Chicago to New Mexico to meet with Fermi, his colleague Sam Allison, and Cyril Smith, who directed the lab’s metallurgy group. Since the visitors couldn’t get passes to enter Los Alamos, the six of them met for lunch in Santa Fe.
On a sunny terrace overlooking a landscape of mesas and mountains, the Chicago group proposed the creation of a new entity, the Institutes of Basic Research, comprised of three specific components: an Institute for Nuclear Studies, an Institute of Metallurgy, and an Institute of Radiobiology and Biophysics. Each institute would be devoted to a major area of research and each would be headed by a world-renowned figure, hopefully one who had played a prominent role in the Manhattan Project. The three scientists the university aimed to attract were, respectively, Fermi, Smith, and Urey.
Emulating the nature of the work at Los Alamos but without the restrictions of secrecy, it was a daring but promising plan for a university. Robert Hutchins, the school’s president, was enthusiastic about the notion. Funding was not likely to be a problem because the climate was different from what it had been before World War II, and government backing for the physical sciences was almost certain to be forthcoming.
With the war ending, Fermi had been actively recruited by the University of Chicago and Columbia University. His already considerable fame was further boosted by what had transpired at Chicago and Los Alamos. About to become the new department chair at Columbia, Isidor Rabi wanted to have him back at Columbia. Rabi regarded Fermi as the greatest physicist he had ever known, next to Einstein. Arthur Compton wanted Fermi for Chicago. About to leave his professorship there for a university chancellorship, Compton told Hutchins that “if Enrico Fermi could be persuaded to take over my professorship of physics, the University of Chicago would profit by the exchange.”
The Chicago proposal, in process for several months, appealed to Fermi’s penchant for cross-fertilization of ideas, the kind of collaboration and cooperation that marked Los Alamos. It would be a first, an interdisciplinary model crossing traditional departmental boundaries, connecting and integrating unique scientific perspectives. With its innovative underpinnings, how could it fail but to attract outstanding scientists and students? It was an offer Fermi could not refuse.
To the delight of the Chicago delegation, all three Los Alamos scientists agreed to the proposal, with Fermi placing the condition that his friend Sam Allison be named head of the Nuclear Studies Institute; he wanted to be freed from administrative duties. He was content with a professorship in physics. Teaching was his passion.
The formation of the Institutes occurred during a propitious period. The future of Los Alamos was uncertain and physicists both young and not-so-old were seeking new opportunities. They realized the time was opportune for change, especially since they had become associated with the success in building the bomb. Academia was appealing, especially if it was predicated on team-oriented research and benefited from generous funding.
The first of the recruits came from Los Alamos. Edward Teller, whom Fermi always found stimulating, was offered a professorship in the Institute for Nuclear Studies, as was Herbert Anderson. From Hanford, Leona and John Marshall came back to Chicago with research positions. From Oak Ridge, Urey packed up shop and made his way to the Windy City. Several of the young Los Alamos physicists enrolled in the Institutes’ graduate programs. A collection of Los Alamos veterans very much to the Pope’s liking would continue to work with him.
An appointment at the Institute for Nuclear Studies might have also been possible for Szilard, but Fermi let it be known that he was not in favor of such a move. Fermi wanted physicists who would work as hard and as steadily as he did and who also, like him, preferred to leave politics to the politicians.
At this point, Hutchins stepped in. An admirer of Szilard, he created a position for him, half-time in the Institute of Radiology and Biophysics and half-time as adviser to the newly created Office of the Inquiry into the Social Aspects of Atomic Energy. With a good salary and no teaching responsibilities, this was an ideal solution for Szilard.
In the six months after Fermi had accepted the Chicago offer, he stayed at Los Alamos winding up research and delivering a series of lectures to its remaining staff members. The talks spanned neutron physics from the beginning to the latest developments. The work done had many useful and game-changing applications to improve living conditions in the world. The most obvious application was harnessing the energy produced in reactors for generating electric power.
That application was immediately recognized as an opportunity by industrialists, notably by DuPont’s Crawford Greenewalt, on December 2 after witnessing the pile
go critical. It was not coincidental that DuPont, ensconced at Hanford, later led the development of large-scale plutonium-producing reactors. Nor was it just chance that the chemical firm Monsanto managed Oak Ridge during the war years. In ensuing years, Monsanto applied chemical techniques it had participated in at Oak Ridge to its burgeoning product lines.
Other applications were to medical technology, especially nuclear medicine. The use of radioactive isotopes in cancer treatment had begun before the war but now gathered speed. And new techniques were arising, including the use of protons produced in particle accelerators to reduce solid tumors. The innovator in this work was Bob Wilson, formerly the head of the research division at Los Alamos, whose 1946 paper on nuclear medicine in the journal Radiology was seminal. Wilson had experienced both positive and negative emotions about his association with the Manhattan Project, but he now turned the experience into a beneficial one.
Wilson focused on basic research for several years and then, in 1976, having proved his administrative skills in Los Alamos, was appointed director of the National Accelerator Laboratory, later renamed Fermilab, less than an hour’s drive from Chicago. In 1996, during one of the last talks he gave, Wilson reminisced:
At Los Alamos, where I had been working for the past five years, no matter how justifiable it may have been, we had been working on one thing, and that was to kill people. When that became crystallized in my mind by the use of the atomic bomb at Hiroshima, it was a temptation, to salvage what was left of my conscience, I suppose, and think about saving people instead of killing them. I jumped into the most obvious thing I could do next: because one could hurt people with protons, one could probably help them too.
Not all Los Alamos scientists shared Wilson’s desire to make amends. Some wanted to continue along the path of building an arsenal of weapons or, like Teller, explore developing even bigger bombs. Many gravitated back toward university life. In the words of Hans Bethe, “We all felt that, like the soldiers, we had done our duty.” Of the many who were immigrants, like Fermi, they had obeyed the American oath of citizenship that reads, “I will perform work of national importance … when required by the law.” Undoubtedly they, with their American compatriots and British collaborators, had performed work of “national importance.” But their work also contributed to the nuclear dilemmas that persist to this very day.
PART 5
HOME
35
PHYSICIST WITH A CAPITAL F
Hiroshima and Nagasaki acted as exclamation points for America’s dominance as a world power. Already well on its way to becoming a major economic and political force, the young country of immigrants and refugees was now the undisputed leader in science. Enrico Fermi, at age forty-five, stood at its forefront, his new homeland’s greatest physicist. He was, as succinctly described by one of his Italian peers, a physicist with a capital F (the Italian word for physicist being fisico).
Fermi’s primacy did not hold in terms of being a physicist with political influence. Oppenheimer walked those corridors virtually alone, with ease and acumen. And Fermi’s primacy was not true in terms of public image. Einstein, in his perch at the Institute of Advanced Study, had caught the world’s imagination and adulation. But Chicago, home to multitudes of immigrants, claimed Fermi as its own. The city’s newspapers celebrated him and other news media embraced his accomplishments.
Americans were still reeling from the magnitude and mystery of nuclear power. The Smyth report aimed to elucidate these complexities to them but it took America’s most accessible medium to educate the public, not only about the history of the bomb but, perhaps more important, about how to harness nuclear energy for peaceful purposes. In a documentary entitled The Quick and the Dead, the NBC broadcast network tackled explaining the dangers and promise of atomic energy. The title was not welcoming, but the host of the series was. Listeners were riveted as Bob Hope, America’s much-loved comedian, presented the four-week miniseries with a cast of familiar actors, including the famed Helen Hayes as Lise Meitner. Fermi’s character was prominent. Neither politician nor icon, he had been popularized.
Fermi, never comfortable in the spotlight, tried to avoid it. Even when receiving the Nobel Prize in 1938, he did not like being the center of attention nor the event’s pomp and circumstance. After World War II, Enrico was flooded by awards, honors, and medals that he graciously and modestly accepted. The impassioned debates that followed the dropping of the bomb drew him into the maelstrom of discussions about how nuclear energy should be applied and regulated in the future. Fermi’s reputation inevitably made him part of controversies he would have preferred to dodge. But he could hardly do so, given that the bomb, as described by one politician, was “the most important thing in history since the birth of Jesus Christ.”
In less flamboyant language, Major General Leslie Groves wrote to Fermi on September 28, 1945, thanking him for his war effort:
Your scientific skill and judgment, your energy and ingenuity, and your self-sacrificing devotion to our cause are beyond praise. The forces of nuclear energy, which you helped so significantly to develop for use against the enemy, will, we pray, be wisely controlled in the days to come to ensure peace and to further the welfare of mankind. But no future events can dim the splendor of the results attained in the immediate past through our ability to make military use of these forces. For your indispensable part in this attainment, I thank you, on behalf of the War Department, as the agent of the American people.
While firmly embedded in the minds of a wide public, Fermi was also revered by “his own”—rank-and-file physicists, budding stars, and eager recruits alike. No one matched Fermi. People looked to him for instruction, guidance, and inspiration. A much wider audience was newly appreciating the role that a small group gathered on a Chicago squash court had witnessed four years earlier.
Part of Fermi’s renown was due to the fact that the world had changed and physics was changing as well. The twentieth century’s early decades, the era of revolutionary theories such as relativity and quantum mechanics, had been stunning but had passed. Now was the time for a continual interplay between experiment and theory, for interpreting clues offered by powerful scrutinizers of both the microscopic and the macroscopic. The thrust of these scientific endeavors was to make use of new tools and to think big. Government funding was flowing at unprecedented levels, forcing decisions on how best to utilize those monies.
Fermi accurately sensed the changing landscape and found it much in accord with his natural inclinations. His most famous contributions to physics were not leaps into the unknown. In the case of neutron bombardment, he had simply been searching for a projectile that could penetrate the nucleus unperturbed. As for Fermi’s weak interaction theory, it came by looking for how quantum field theory could explain the nagging experimental question of missing energy in beta decay.
In moving forward, Fermi believed he was continuing a natural progression rather than attempting to embark on a revolutionary path. Ernest Rutherford had discovered the atomic nucleus in 1911 by observing the deflection of alpha particles bombarding a thin gold foil. Using a more powerful beam, James Chadwick had uncovered the neutron in 1932. It had been clear to Fermi since the late 1930s that the development of the powerful particle accelerators known as cyclotrons would cause that frontier to move forward. It had become possible to probe matter on smaller scales, to go deep inside the nucleus and hopefully uncover the nature of the mysterious forces holding neutrons and protons together inside it.
Fermi’s incremental approach to physics kept him far more relevant than any of the great theoretical physicists he had admired in his youth. Now physics was looking to experiments for indications of its future and Fermi was the only physicist to combine being a great experimentalist with being a great theorist.
The older Einstein, Bohr, and Schrödinger, still esteemed, were well past their productive prime. To a large extent, the dominant theorists of Fermi’s generation, such as Dirac, Heisenberg,
and Pauli, had remained in familiar territory, still searching for an equation that would explain the behavior of nuclear constituents. By the postwar years Dirac had become, as his recent biographer characterizes him, “an ambassador of mathematical beauty.” Heisenberg, who had been touting his unified field theory for years, finally unveiled it with great fanfare in 1958. It was viewed unfavorably by almost everybody, including Pauli, who had initially collaborated with him. His approach seemed mired in the past.
The next wave of leaders in physics was not coming forth from Göttingen, Munich, Leipzig, or Zurich, but from American academic institutions such as Berkeley, MIT, Princeton, and Columbia. And more than anywhere else they appeared at the University of Chicago, in America’s heartland, following a trail set by Fermi. As one scientist commented, “Fermi was the Pied Piper who brought them.”
The Chicago physicists were eager to attack a formidable problem that had surfaced but not been resolved in the 1930s: what holds nuclei together and why do they sometimes split apart? In the miracle year of 1905 when he proposed his theory of special relativity, Einstein had also envisioned the electromagnetic force as carried by particles. They would come to be known as photons, particles with no mass. In 1935, the Japanese physicist Hideki Yukawa said that the nuclear force might be carried by an altogether different kind of particle: a meson.
Quantum field theory provided a description of mesons being exchanged back and forth between the neutrons and protons in the nucleus. Mesons appeared and disappeared in a flash. Observing a meson was a problem, because Yukawa’s theory asserted they had a large mass. The mass of a meson was estimated to be approximately 15 percent of the mass of the proton. The cyclotrons of the 1930s offered no hope of directly detecting mesons, since these accelerators could not provide enough energy to produce such a massive particle. However, advances in accelerator technology in the postwar period made possible what had previously been impossible. A much enhanced version of the cyclotron, referred to as a synchrocyclotron, boosted particle energy significantly.