Brotherhood of the Bomb

by Gregg Herken

  Ten days later, however, the Tennessee Eastman representative in Oak Ridge telephoned Berkeley with more bad news: the electrical, vacuum, and cooling systems for the Alpha racetracks had all developed problems.69 Work on the Calutrons came to a virtual halt, pending Lawrence’s visit at the end of the month.

  Ernest arrived to discover that mere enthusiasm could do little to salvage the situation at Y-12—where the racetracks had been shut down by faulty welds, electrical shorts, and incompetent technicians.70 Unable to suggest a quick remedy, he left by train for a meeting of laboratory directors in Chicago.

  Suffering painful muscle spasms in his back and a lingering sinus infection, Lawrence checked into the city’s Stevens Hotel. After first attending the lab directors’ meeting—he was carried into the room seated in a chair, rigid and grimacing—he telegraphed his brother for medical advice. A former Harvard classmate of John’s arranged for him to be admitted to the University of Chicago’s Billings Hospital.71

  Stopping by the hospital on his way to Los Alamos from Boston, Luis Alvarez was shocked to find Lawrence prostrate and in poor spirits. Alvarez thought exhaustion and depression, not physical pain, the real cause of Ernest’s condition.72 Oppenheimer and Arthur Compton, also hoping to see Lawrence, were turned away by worried doctors. When treatments at the hospital failed to provide the expected relief, Ernest decided to go home to Berkeley rather than return to Tennessee.73

  By mid-December, Lawrence was once again running the Coordinating Committee meetings, his back as well as his spirits recovered. Gradually, the problems with the Calutrons began to be solved. Stone and Webster installed filters to take moisture out of the transformer oil. Westinghouse announced that it had ironed out the kinks in the vacuum system. Allis-Chalmers agreed to remanufacture magnet coils that had shorted out because of insufficient space between the windings. Groves brought in a former civilian contractor to replace the army officer in charge of construction at the site.74

  It was, nonetheless, clear to all that Eastman’s original plan to run Y-12 without help from the Rad Lab was no longer realistic. Lawrence launched a frenetic effort to recruit workers from the lab to go to Oak Ridge. Old-time cyclotroneers as well as new arrivals came to dread Ernest’s cheerful query, “How would you like to go to Tennessee?”75

  On New Year’s Eve, Lawrence telephoned Oak Ridge. “All the boys that you would like to have are coming,” he promised the Eastman representative.76 The first contingent of nearly 100 recruits would begin arriving in a few days. Ernest delayed his own departure until mid-January, to coincide with the scheduled start-up of the second Alpha racetrack. After chairing one final meeting of the Coordinating Committee in Berkeley, Ernest announced that the group was being disbanded. It would be reorganized and hold its next meeting in Tennessee.

  * * *

  Even with Pash gone, the case of the mysterious professor and of his three still-anonymous contacts continued to prey on Groves, who had been recently reminded by Lansdale of Oppenheimer’s promise from the summer.

  In early December 1943, Groves flew to Los Alamos. Meeting alone with Oppenheimer in the office that he kept at the lab, Groves ordered Oppie to divulge the identity of the go-between who had contacted the scientists. Oppenheimer promptly named Haakon Chevalier, the man he had told Lansdale was “quite a Red.”

  However, when Groves asked Oppenheimer to identify the three men whom Chevalier had approached, Oppie agreed to do so only on one condition: that Groves promise not to divulge the names to the FBI. Believing that the three were undoubtedly among Oppie’s four graduate students, whom the army already had under surveillance, Groves agreed.

  But what he heard next surprised him. There had been only one person contacted by Chevalier, Oppenheimer said: his brother, Frank.

  Filling out the story, Oppenheimer told Groves that several months earlier Chevalier had approached Frank about the possibility of either passing secrets on the bomb project to the Russians or persuading his brother to. Uncertain how to respond, Frank had come to Oppie for advice. His recommendation, Oppenheimer told Groves, was that his brother should have nothing further to do with the scheme—and he had later given Chevalier his “comeuppance” for trying to recruit Frank as a spy.77

  On the flight back to Washington, Groves wondered whether Oppenheimer was telling him the truth—or whether Oppie had simply introduced Frank into the story as a way to justify his own earlier failure to notify the army of Chevalier’s overture. More important, Groves realized that by promising not to divulge Frank’s name to the FBI, he, too, was now unwittingly a party not only to a lie but to a felony—namely, withholding the truth about an espionage conspiracy from federal authorities in wartime.

  Back at the New War Department Building, Groves called Lansdale and Army Major William Consodine, his chief troubleshooter and lawyer, into his office. Putting a yellow legal pad in front of them, Groves asked each man to write down his guesses as to the names that Oppenheimer had given. Lansdale wrote down three names, all presumably from Pash’s list. Consodine put down only one—Frank’s.78

  When Groves revealed what Oppie had told him, the trio discussed whether the general should consider himself bound by his promise to Oppenheimer. As Groves’s lawyer, Consodine argued that the security of the nation represented a higher and overriding obligation.79 But Groves felt that the bomb project itself might be fatally compromised if he lost Oppenheimer’s trust by violating his pledge. When Groves raised the possibility of a secret prosecution of Chevalier and Eltenton, Consodine warned that not even the wartime emergency allowed the suspension of due process.80

  Either on his own—or with Groves’s willing connivance—Lansdale decided that he would verbally inform the FBI of the information received from Oppenheimer, but without putting anything down in writing.81

  Remarkably, Groves chose not to let his own former deputy, the MED district engineer, Kenneth Nichols, in on the secret.

  On December 13, Nichols wired Lyall Johnson at Berkeley that Oppenheimer’s intermediary was Chevalier. But Nichols’s cable unknowingly perpetuated the earlier fiction that Oppie had told Pash: “Oppenheimer states in his opinion Chevalier engaged in no further activity other than three original attempts.”82 Nichols sent similar telegrams that same day to de Silva at Los Alamos and Calvert at Oak Ridge. Pash, who was already in Italy, working for Alsos, remained unaware of the latest developments.83

  That same evening, Lansdale went to FBI headquarters to personally inform Hoover aides Lish Whitson and Frank Tamm that Haakon Chevalier had tried to recruit Robert Oppenheimer’s brother to spy for the Soviet Union.84

  * * *

  The first contingent of cyclotroneers arrived at “Dogpatch” in the early days of 1944 to find things in utter disarray.85 Delayed by another bad cold, Lawrence, with Cooksey in tow, detrained at Oak Ridge on January 20 to take control of the operation. Ernest was assigned a comparatively luxurious E-unit apartment on Tennessee Avenue, near the camp store and movie theater.86 With the help of a little long-distance troubleshooting by Brobeck, some of the teething problems with the Alpha racetrack had already been worked out by the time that Ernest appeared.87

  Martin Kamen arrived in the second wave of Berkeley recruits, to supervise the process of chemically separating uranium, only to discover that he had left the package containing the necessary floats and filters behind on the train.88 Kamen subsequently found that even when the racetracks were working properly, only about 10 percent of the orange uranium oxide—the “feed” material—was converted by the Calutron beam into a focused, ionized arc. Of that, only a few percent emerged in the receivers at the other end. Most of the “gunk” was spewed by the beam around the innards of the Calutron. The vacuum tanks had to be dismantled at the end of each run and their contents laboriously scraped, dissolved, and precipitated out to be fed into the machine once more.89

  Lawrence proposed ingenious ways to work around the remaining problems. When the Calutrons began to overheat, he ha
d the Oak Ridge fire department play their hoses upon the cooling towers until temperatures dropped to a safe level. The design flaw was found and corrected. At Lawrence’s request, Frank Oppenheimer flew out to Y-12 late in the month to deal with a corrosion problem, caused when chlorine used in the chemical process reacted with nickel in the stainless steel pipe.90 Copper liners proved the solution and Frank returned to Berkeley.

  At the end of January 1944, Alpha Calutron 2 became the first racetrack to begin continuous operation. The mistakes and problems that surfaced in the initial start-up meant that the original Alpha track would not be back on-line till March. Recently imposed security strictures added another headache. Henceforth, all personnel assigned to Y-12 from Berkeley had to be cleared first by the army.91

  With the confidence born of experience, however, the pace began to quicken that spring. In March, the first U-235 was shipped to Los Alamos—a few dozen grams. It found immediate use in experiments at the lab.92 By the end of April, all four of the original Alpha racetracks had been upgraded to the four-beam design and were in round-the-clock operation. In May, the first Beta track ran successfully, boosting the enrichment of the uranium received from the Alpha tracks.93

  Barring discovery of any new and unforeseen technological impedimenta, Lawrence was beginning to be optimistic that Dogpatch could provide the uranium to meet Compton’s revised schedule—a bomb by mid-1945. The chief uncertainty remaining was the design of the weapon.

  * * *

  Many of Lawrence’s boys who had not been sent to Oak Ridge began to show up at Los Alamos early in the year. By February 1944, Emilio Segrè was a group leader in the Physics Division.94 Luis Alvarez finally got to the desert lab from MIT in late spring, following a detour to the Met Lab at Oppenheimer’s request. Alvarez was assigned to work with George Kistiakowsky, another recent arrival, on electrical detonators for the implosion bomb.95 After helping to find equipment and recruit other scientists for Los Alamos, Ed McMillan worked on early implosion experiments and, later, on design of the gun.96

  The main effort at the lab was now focused upon the gun and the implosion gadget, although work was stalemated on the latter, Tolman reported to Groves in March. The “prime objective” for the remainder of the year, Oppenheimer wrote Groves, was “to bring to a successful conclusion the development of the implosion unit with (U-235).”97

  Alternative concepts for the atomic bomb had been gradually discarded, one by one. An imaginative proposal put forward by Bohr was studied by Bethe and Teller and found to be “a quite useless military weapon,” Oppenheimer informed Groves.98 Work on the hydride bomb, the weapon that Teller had championed early on at the lab, was finally, and reluctantly, abandoned by him in the winter of 1943–44. Studies showed that uranium hydride could not be easily compressed in a gun, and that any explosion that resulted would be far less efficient than a weapon using metallic uranium or plutonium.99 The yield of Teller’s hydride would be “negligible or less,” concluded Princeton’s Richard Feynman.100

  But a far more serious problem would soon come to light, in an experiment by Segrè. When the first significant sample of reactor-produced plutonium arrived in early summer, Segrè’s group was surprised to find it had a rate of spontaneous fission five times that of the plutonium produced on the 60-inch at Berkeley. Further studies confirmed that reactor-bred plutonium contained too much Pu-240, an isotope with a high rate of spontaneous fission, to be usable in a gun-type bomb. Upon firing, a plutonium gun would “preinitiate” and fizzle—spewing molten radioactive metal in all directions.101 Oppenheimer ordered work on Thin Man, the plutonium gun, abandoned.

  The so-called implosion crisis forced a reorganization of the laboratory that August. Oppenheimer gave Bacher and Kistiakowsky the job of making the spherical implosion design—Fat Man—a success, creating two new divisions at the lab for the purpose.102 Calculations carried out earlier by Teller and John von Neumann, a Princeton mathematician brought to the lab as a consultant, had shown how the compression attainable in the implosion design made it potentially far more efficient than the gun. Henceforth, the emphasis at the lab would be upon “fast” implosion and Fat Man.103

  Despite his previous work on the subject, Teller lost interest in the implosion problem as Oppenheimer brought in more of his colleagues to solve it. (Teller’s heart remained with the purely theoretical. A visit to Y-12 earlier in the year had confirmed his belief that the atomic bomb was an engineering, not a physics, challenge. Although he pronounced Y-12 “Super-colossal,” he wrote, “[it is] wonderful that I do not have to live there.”)104 With the hydride having hit a dead end, Teller returned to his first pet project: the Super.

  Since the fall, Teller had been urging that the level of effort on the superbomb be increased at the lab—citing recent reports that the Germans were experimenting with heavy water, and calculations which indicated that less deuterium might be required than originally anticipated.105 Preoccupied with the gadget, Oppenheimer and the lab’s governing board had denied Teller’s request. But Oppie encouraged Edward to continue exploring the possibility of a superbomb with a small group in the Theoretical Division.

  One of the key unanswered question from the 1942 Berkeley seminar that was of relevance to the Super concerned what happened to the radiation created in an atomic bomb. Resolving the issue of the superbomb’s feasibility awaited discovery of whether its internal components permitted or impeded the transfer of energy in the form of radiation. Teller and Konopinski had yet to do the calculations on the phenomenon known as opacity that they had promised to do at Berkeley.106 On a visit to New York, Teller persuaded a friend and confidante, Columbia University physicist Maria Göppert Mayer, to carry out the laborious work that might answer the question. Teller had known Mayer since the mid-1930s, describing her as his “Dutch aunt,” to whom he confessed both professional and personal problems. (“Slender and blond, she had a natural delicacy and grace as well as considerable strength of mind,” Teller later wrote of Mayer. Maria was married to a chemist, and the couple had two small children.)107

  Oppenheimer gave Teller permission to hire Mayer for the opacity calculations, but forbade him from disclosing the intended application. (Teller later recalled their conversation: “I had to tell her it is uranium, and I had to tell her at what temperature.… There was a clear intake of breath. And no more questions.”)108

  But even Teller acknowledged that his own most recent calculations on the Super showed the need for more tritium. The loss of energy due to radiation seemed greater than he had predicted two years earlier. Accordingly, Edward conceded that development of the superbomb “may require longer than was originally anticipated.”109 Oppenheimer agreed to let Teller continue his work, so long as it did not jeopardize the timetable for the fission gadget.*110

  During the early summer of 1944, amid the crisis over Thin Man, Teller had twice refused a request from T Division’s leader, Bethe, to help with calculations on the hydrodynamics of fast implosion. That June, with Bethe’s patience at an end, Oppenheimer transferred Teller out of the Theoretical Division, allowing him to work on the Super on his own.111 Teller also continued to discuss his ideas with Oppenheimer alone for an hour a week. Work on implosion theory was given instead to Rudolf Peierls and members of the British mission at the lab, among whom was Klaus Fuchs.112

  * * *

  Fuchs had come to the United States the previous December and began passing secrets to the Russians almost immediately. Shortly before he left England, Rest had been asked by his Soviet control what he knew about the electromagnetic method of separating uranium. The question had surprised Fuchs, who, at the time, knew nothing of Lawrence’s Calutrons. Rest concluded that the Russians must also have a spy at Berkeley.113

  On February 5, 1944, Fuchs met with his new espionage contact, New York chemist Harry Gold (Gus), on the corner of Fifty-ninth Street and Lexington Avenue. There Rest told Gus about “the process for the separation of isotopes of Enormous,” according
to a coded cable that Kvasnikov sent to Fitin in Moscow a few days later.114 The other information received from Fuchs included details on “the electron method developed by Lawrence,” and the fact that U-235 obtained by gaseous diffusion was to be further enriched by “the electron method for final separation”—the Beta Calutrons, which would not begin operating at Y-12 for another three months.115

  In Moscow, Kurchatov was in possession of a list of nearly 300 secret technical reports on the Manhattan Project. Many if not most of the papers came from agents in British laboratories, which continued to receive classified reports from the United States.116 Kurchatov’s memos to Pervukhin indicated that the Russians now knew fission cross sections as well as the critical mass of uranium and plutonium. But there were still important gaps in his knowledge, Kurchatov complained. Missing, for example, were the results of experiments at Berkeley on the fissioning of plutonium under fast neutron bombardment. Kurchatov drew the attention of Pervukhin to this lacunae with his blue pencil: “Information on the results of this work by Seaborg and Segrè is therefore of particular importance to us.”117

  On August 12, 1943, the Rad Lab itself had figured in a coded telegram that Pavel Mikhailov (code name Molière), the GRU rezident at the Soviets’ New York consulate, sent to Fitin in Moscow: “In Sacramento, California, in the Radiation Laboratories, large-scale experimental work is being conducted for the War Department. Working there is a progressive professor (blank), whom one can approach through the Korporant.”118

  Mikhailov’s message identified the Korporant—GRU’s term for a member of the Communist Party—as Paul Pinsky, the FAECT organizer whom Oppenheimer had helped to give the union a foothold in the Bay Area.119