Big Science

by Michael Hiltzik

  Only six weeks later would his whereabouts become known, and then only by the bare bones: he was at MIT, working on an unidentified “war project.” At the end of November, Seaborg reached him by letter with a proposal to collaborate on the search for 94 in McMillan’s absence. Responding with traditional Rad Lab collegiality, McMillan wrote back that he did not expect to be back in Berkeley for quite some time (showing how little he credited Ernest’s promise that his East Coast sojourn would be brief) and saying he would be pleased if Seaborg took over the project in the meantime. Seaborg joined with Joseph Kennedy, a newly appointed chemistry instructor with the gangly physique of a scarecrow and a gentle drawl that proclaimed his North Texas origins, and brought the plan to Ernest.

  Lawrence viewed the quest for 94 through a double prism. The discovery of a fissile isotope that could be separated from its parent by chemical means might quell the skepticism still bogging down the uranium program. Then there was, as always, his desire to demonstrate the cyclotron’s unique properties. If element 94 was to be found, it could be found only through the intense and repeated bombardment of uranium—and the only machine capable of reaching the required energies was the sixty-inch cyclotron. With Lawrence’s endorsement, Seaborg’s project was awarded top priority for time on the Crocker Cracker.

  By January 20, 1942, Seaborg was confident enough to write McMillan with assurance that the bombardments had produced an unknown isotope of element 94. “Things look good for element 94,” he wrote, adding the cautionary note: “No one else knows about the most important of these results except Wahl and Kennedy . . . The committee [that is, Briggs] will want us to keep the results very secret.” He staked the team’s claim to the discovery with a letter to the Physical Review dated January 28, 1941. “We felt like shouting our discovery from the rooftop, but the war had changed everything,” he reflected later. In accordance with Lyman Briggs’s secrecy rules, their letter would be withheld from publication until April 1946. By then, Seaborg would observe, the existence of element 94 had been revealed to the world “in the most dramatic form possible”: with a detonation in the skies above Nagasaki, Japan.

  Seaborg’s next step was to test the new element’s fission cross section—in other words, to determine whether it could sustain a chain reaction and make a bomb. This new phase of research required the irradiation of uranium on a heroic scale, with the goal of producing enough 94 to perform the necessary experiments. Seaborg, now working with the Italian refugee physicist Emilio Segrè, calculated that a week’s bombardment of 1.2 kilograms of uranium (a touch more than 2.5 pounds) by the sixty-inch cyclotron would yield one microgram—a millionth of a gram—of element 93. A further calculation gave Seaborg pause: the irradiated uranium would be ferociously radioactive. The lab had been so blasé about the radioisotopes produced at the Crocker Lab that it routinely sent some of them through the US Mail; but this sample would have to be treated with sedulous respect, handled at greater than arm’s length by personnel wearing lead gloves and goggles.

  One day in early March, Seaborg and Segrè carried a hot sample of bombarded uranium out of the Crocker Lab in a lead bucket suspended from a long pole. Swaddled in leaded clothing, they crossed to Gilman Hall and crab-walked up two flights of stairs to a vacated laboratory. There they separated out 93 by repeating a tedious sequence of heating, evaporating, dissolving, precipitating, and centrifuging over three long days. They poured their final precipitate into a platinum dish smaller than a dime, boiled off the liquid, and slathered the residue with a layer of Duco Cement. The dish was glued to a piece of cardboard, labeled “Sample A,” and left alone to decay into element 94. That took three more weeks. At last, by Seaborg’s reckoning, they had one quarter of a millionth of a gram of element 94.

  Then came what he called the moment of truth: they brought the sample to the thirty-seven-inch cyclotron, placed it in a neutron beam, and waited for their detector to announce the kicks that indicated fission. The sounds came instantly and unmistakably. Later tests would tell them that isotope 239 of element 94—that is, a nucleus pregnant with 94 protons and 145 neutrons—was nearly twice as fissile as U-235 (later experiments would refine this result to 1.24, still appreciably more fissile than the uranium isotope) and that its half-life was somewhere in the neighborhood of 30,000 years (the true value is 24,100 years). That was surely long enough to provide the stability required of a bomb core. By transmuting common uranium into a fissionable product that could be extracted chemically, Seaborg calculated, they could increase the supply of raw material available for a bomb by a hundredfold. It was May 1941. Around the end of that year, after McMillan had named his element 93 neptunium to commemorate the eighth planet from the sun, Seaborg followed suit and named 94 for the ninth planet, which had been discovered only in 1930. It became known as plutonium.

  • • •

  A few weeks after Pearl Harbor, Arthur Compton summoned Seaborg to Chicago for a heart-to-heart talk.

  The subject boiled down to this: Could Seaborg devise a chemical process for separating element 94 from the stew of radioactive fission products in which it was mixed after the bombardment of uranium? Compton specified that the work would have to be done at breakneck speed and that the process would have to be scalable to an industrial level. Without hesitating, Seaborg answered yes. He would have many opportunities later to curse himself for this “rather hasty expression of confidence delivered by a young man not likely to admit to probable failure, who was too ignorant to realize the ultimate magnitude of the project or even his inexperience about the intricacies of large-scale production.” He might have been even more unnerved had he known how skeptically his seniors regarded his headstrong pluck. Bush and Conant both advised Compton that in pressing ahead on plutonium, he was making a long-shot bet, for no plutonium separation process had even been demonstrated in the lab.

  Compton stood his ground bullheadedly. “Seaborg tells me that within six months from the time plutonium is formed, he can have it available for use in the bomb.”

  Conant snorted dismissively. “Glenn Seaborg is a very competent young chemist,” he said, “but he isn’t that good.”

  But he was. Once he settled on a production method, Seaborg beat the deadline by four months.

  • • •

  Following the $400,000 contract awarded by S-1, the Rad Lab outgrew its quarters rapidly. As early as the beginning of 1941 the staff had expanded to nearly one hundred. The feel of a tight-knit group pulling together under Ernest Lawrence’s paternal eye was slipping away. “It wasn’t a cozy gang,” Kamen lamented in a letter to McMillan after the Rad Lab Christmas party that year, attended by scores of strangers. To house his burgeoning staff, Ernest commandeered every vacant room in LeConte Hall and, with Sproul’s permission, completely took over the university’s newest instructional building, then officially designated simply as the “New Classroom Building.” (It would later be christened Durant Hall in honor of Berkeley’s first president.) Kamen’s strangers mixed with previously departed veterans, for Ernest was summoning his cyclotroneers back from their nationwide diaspora—back from Cornell and Princeton and Washington University in St. Louis, and back from Westinghouse and General Electric—to help him perfect the electromagnetic separation of uranium-235.

  When a warm body was needed, Ernest would recruit almost off the street, like a Hollywood talent spotter dragooning a soda fountain girl into instant stardom. To manage the construction of the 184-inch cyclotron, he appointed Ed Strong, a Berkeley philosophy professor, whose home Ernest had helped finance with his Nobel Prize money as a way of investing informally in California real estate. After Strong described at dinner one evening his experiences supervising the carpenters, plumbers, and electricians building his house, Lawrence drove him up the hill to the Rad Lab site. The new cyclotron’s 4,500-ton magnet, the largest in the world, was still standing in the open air and other parts were packed in huge crates. “I need somebody who on the one hand can work with the mech
anics, who talks their language, and, on the other hand, won’t be run over by the physicists and the engineers,” he explained. Strong would spend the war years overseeing one of the largest scientific construction sites in the world. After the war’s end, however, he turned down Ernest’s offer to continue as the lab manager in order to resume the classroom teaching of Hegel and Marx.

  Lawrence was once again making fresh footprints into a new world, an experience he had not enjoyed since the construction of the twenty-seven-inch cyclotron. Those who were working with him for the first time were instantly infused with his confidence, not to mention his sense of urgency. Even Vannevar Bush, who had spent his career surrounded by accomplished scientists, felt overcome by the “stimulating” and “refreshing” atmosphere in the lab when he paid a visit in February 1942.

  The chief drawback to the lab’s expanding relationship with the government was the growing burden of security. Briggs’s rules prohibiting publication of fission-related articles soon expanded to a blanket ban on any discussion of the topic outside the confines of the laboratory. The scientists’ initial reaction to these increasingly draconian strictures was to treat them whimsically. Seaborg’s group started referring to element 94 as “copper.” That worked for a few months, until they needed actual copper fittings for their equipment, at which point they referred to the genuine metal as “honest-to-God copper.” The scientists were forbidden to ever refer to uranium or plutonium by name. (“All I knew was that uranium was a dirty word, and I wasn’t supposed to use it,” Molly Lawrence recalled.) Eventually they took to designating these elements by a code assembled from the final digits of their atomic number (92 for uranium and 94 for plutonium) and their isotopic weight, so that uranium-235 became known as “25” and plutonium-239 as “49.” This code persisted through the war.

  Having been upbraided by Cockcroft for the Rad Lab’s publication of atomic research in 1940, Ernest soon accommodated himself to the demands of military secrecy. These included the regime of “compartmentalization” decreed by General Leslie Groves, the newly appointed head of the bomb project, to limit the knowledge any scientist could have beyond what was needed to perform his or her specific task. That does not mean that government security officials invariably found Lawrence cooperative, especially when their suspicions fell upon Rad Lab members he considered indispensable. “We had more trouble with Ernest Lawrence over personnel than any four other people put together,” Lieutenant Colonel John Lansdale, Groves’s security chief, was still complaining many years after the war. His specific reference was to a contretemps in August 1943 over Rossi Lomanitz, a twenty-one-year-old Rad Lab physicist who was valued as a protégé by both Lawrence and Oppenheimer. Lawrence planned to place Lomanitz in charge of the electromagnetic separation work at Berkeley, but the security men had other ideas. Viewing Lomanitz as a dangerous leftist, they plotted to remove him from sensitive nuclear research via the simple expedient of drafting him into the army. Lawrence demanded a face-to-face meeting with Lansdale over Lomanitz’s fate. It was not a warm encounter. Lansdale recalled, “Ernest Lawrence yelled and screamed louder than anyone else about us taking Lomanitz away from him.” But in the end, the army got its way—and got its man.

  Lawrence’s approach to security pressures in the bomb program soon evolved under pressure and the omnipresence of security officials in his life. “The crushing responsibilities of his later years,” Martin Kamen would observe, “hardened his attitudes about people and increased his suspicions of their motivations.”

  Kamen was the most prominent victim of Lawrence’s increasing rigidity on security matters, for it cost him his job at the Rad Lab and almost his entire career. Despite the importance of Kamen’s work—his discovery of carbon-14 was a notable scientific achievement, and his indefatigable management of radioisotope production a contributor to the lab’s reputation as a reliable supplier of research materials—he had never been part of Lawrence’s inner circle. He was a chemist, not a physicist, with an intellectual temperament much closer to Oppenheimer’s than to Lawrence’s. A talented musician, he socialized with what he described as an “exciting group of leftist intellectuals and bon vivants” in San Francisco. Also, he was Jewish, and although Lawrence was not an anti-Semite, he could be oversensitive to ethnic distinctions, possibly because of his upbringing in an ethnically homogenous rural community. In describing Kamen to his friend Alex Allen, who was hiring at the Bartol Research Institute in 1937, Lawrence wrote: “He is Jewish and in some quarters, of course, that would be held against him, but in his case it should not be, as he has none of the characteristics that some non-Aryans have. He is really a very nice fellow.” (Whether Allen offered Kamen a job is unclear, but in any event, Kamen stayed at Berkeley.)

  By early 1943, Kamen’s social contacts brought him under the eye of army security. He was aware that his home phone was tapped and his house watched by comically conspicuous security men, who would sit for hours in the front seat of a parked car with the motor running. Despite the surveillance, Kamen remained imprudently nonchalant about his social activities. One night he was spotted dining with Gregory Kheifetz, the local Soviet vice-consul, whom he had met at a party at the home of the violinist Isaac Stern. The dinner was Kheifetz’s way of thanking Kamen for his having arranged radiation treatment for a Soviet diplomat’s leukemia in John Lawrence’s lab, but it was viewed with much greater gravity by the security men. Not long after the dinner, Cooksey called Kamen into his office. His face ashen, he wordlessly handed over a one-page typed document ordering Kamen to leave the lab immediately. He would never return.

  With virtually every academic lab in the country working under government contracts, Kamen could not find a research job anywhere. He sat out the war as a technical inspector at the Kaiser shipyards in nearby Richmond, California. For years, the chemist harbored a bitter resentment of Lawrence, who had plainly dumped the task of firing him in Cooksey’s lap and absented himself from the Rad Lab while the deed was done. “EOL thinks I told the Russians something,” Kamen complained to Oppenheimer. “How he could have fallen for this cock-and-bull story is beyond my comprehension except that he may have wanted to.” The cloud over Kamen’s career did not lift until the onset of peace, when he was invited by Arthur Compton to supervise the construction of a cyclotron at Washington University in St. Louis, where Compton had been named chancellor. As it was later revealed, Compton had called Lawrence to inquire about Kamen, and received a glowing recommendation and the assurance that he “felt no doubt with regard to Kamen’s essential loyalty to the United States.”

  The security restrictions also burdened Lawrence personally, and not merely because they added a new administrative concern to his expanding responsibilities. They also narrowed his options for respite from his care-laden work. Arthur Compton, who faced similar pressures and was accustomed to freely discussing his research with his wife, arranged to have her cleared by security; Seaborg, a newlywed whose bride—Ernest Lawrence’s secretary, Helen Griggs—had been vetted before the war so that she could type Rad Lab scientists’ technical reports, did not even need to take that step.

  Ernest, however, had never been one to talk about his work at home. He was not inclined to start now, when it was more sensitive than ever. His resulting isolation only increased his fatigue and nervous tension. He was on the road almost constantly, swallowing his deep aversion to airplane travel merely to get from one meeting to another; for the first time in their married life, Ernest and Molly spent Thanksgiving and Christmas apart. The closest he came to confiding in her was to hand her a list of the stops on his itinerary, but if she asked why he was going to any particular place, he would snap, “It’s none of your business.” “So I got out of the habit of asking questions,” she recalled.

  • • •

  As Lawrence expected, the skills of the mass spectrograph operators improved dramatically with experience, expanding the device’s capabilities; by mid-January, a nine-hour run yielded 18 m
icrograms of uranium enriched to 25 percent U-235. The sample weighed about a thousandth of a grain of sand, but it was thirty-four times more concentrated with the fissionable isotope than was natural uranium. A month later, the lab had accumulated 225 micrograms enriched to 30 percent U-235. This was divided into three samples, two of which were dispatched to Compton at the bomb project’s Chicago laboratory, known as the Metallurgical Laboratory, or “Met Lab,” and to Mark Oliphant, who was in charge of the British government’s uranium program at Cambridge University.

  Lawrence continued to press ahead. Even as his staff was mastering the first-generation separator, he started sketching out a new one. This device was shaped like the letter C to accommodate the semicircular ion beam; it was smaller than the original tank, so its internal vacuum would be easier to maintain, and was fitted with an ion source ten times as powerful as the original. The upgrade also featured a new type of isotope collector, which was shaped like a box with separate compartments for each isotope and was water-cooled to keep it from melting under the torrent of energized ions. In acknowledgment of the University of California’s tolerant hospitality toward a laboratory that was now devoted almost entirely to government work, Lawrence dubbed the new unit the calutron.

  Within days of its installation between the magnet poles of the thirty-seven-inch, the calutron exceeded Lawrence’s expectations. He telephoned Bush with the news, his enthusiasm coming through so loud and clear over the long-distance line that Bush dashed off a note to FDR declaring that “there is a possibility of production of fully practicable quantities of material by the summer of 1943 [fifteen months away].” That would beat Compton’s timeline by six months.

  Nor was Lawrence finished. So far the calutron’s production was minuscule and its reliability imperfect, but he was already planning to replace its 10-milliampere ion source with one offering yet another tenfold increase in power. But that was itself a mere stepping stone to greater things. Having shown that the calutron would work in the thirty-seven-inch magnet, he was now prepared to sacrifice his crown jewel to the war effort: the enormous 4,500-ton magnet ordered for the he-man cyclotron and still standing in solitude on the hillside above campus.