by Gregg Herken
While the investigation of the so-called Kenilworth Court incident continued, Oppie received an unsolicited offer of assistance. “If at any time you should feel that it were wise, I would be pleased to have you make a statement of the general tenor of that which follows,” Leslie Groves wrote from his office at Remington Rand, where the general had gone following his retirement from the army. The letter continued:
General Groves has informed me that shortly after he took over the responsibility for the development of the atomic bomb, he reviewed personally the entire file and all known information concerning me and immediately ordered that I be cleared for all atomic information in order that I might participate in the development of the atomic bomb. General Groves has also informed me that he personally went over all information concerning me which came to light during the course of operations of the atomic project and that at no time did he regret his decision.
“I don’t believe that you will find any need to make use of any such statement, but you might,” Groves advised. “You might wish to show it to some individual for his use in handling unpleasant situations, if they arise.”11
The occasion did not arise. Unable to shake Oppenheimer’s story, and considering Paul Crouch a somewhat unreliable witness, the FBI decided against pressing the case.12
Once more for Oppenheimer, salvation had come from a most unlikely place. Campaigning in California, HUAC congressman Richard Nixon expressed “complete confidence in Dr. Oppenheimer’s loyalty” the day following Sylvia Crouch’s testimony. While the truth behind the Kenilworth Court incident remained a mystery, the story quickly faded from the headlines.*13
To Oppie, nonetheless, the effects lingered. “I took it all very badly and feel now like a man slowly convalescing from a serious illness,” he wrote Robert Bacher.14
Because of the controversy that continued to dog him, Oppenheimer briefly considered resigning the chairmanship of the General Advisory Committee that fall, shortly after the GAC’s new members were announced. Gordon Dean had elected to replace the committee members whose terms were expiring—Seaborg, Fermi, and Hartley Rowe—with three scientists who, in Borden’s words, “strongly believe in the necessity of the H program.”15 Ironically, one of those who had urged Oppenheimer not to step down from the GAC was Dean.16
Oppie’s brother was in far more serious trouble. Although no longer on the FBI’s Key Figure list, Frank was still being periodically harassed by bureau agents, who asked local ranchers why their neighbor seemed to have so few cattle. (“It seems such a waste of God’s talent to make a good physicist into a mediocre rancher,” wrote a former colleague.) Since his firing by Minnesota, he had been unable to find another job in academe. Despite Robert’s personal lobbying on Frank’s behalf, he was turned down for teaching positions at Chicago, Cornell, and MIT—where some faculty members were “overly impressed by ‘the great lie’ Frank told,” Oppie was confidentially informed. A visit by the younger Oppenheimer to Caltech that summer was “painful,” Bacher wrote Oppie.17
* * *
The fact that Robert Oppenheimer remained at the helm of the GAC and continued to serve on several other influential committees in Washington was a cause of increasing dismay to Borden, Strauss, and others in the capital.
On November 20, 1950, Borden requested Oppenheimer’s FBI file from Hoover. The staffer’s particular interest was the Chevalier affair and the alleged Kenilworth Court meeting. Bryan LaPlante, an AEC security official, borrowed the dossier the following day.18
Despite having new, more conservative members, the GAC had done nothing since the H-bomb decision to make it more popular with its critics, who were growing in both number and boldness. Among them was Ernest Lawrence, whom Acheson had recently appointed to a State Department panel advising on nuclear weapons policy. Distinguishing between “working scientists” like himself and “talkers,” Lawrence observed disdainfully that “those who once thought the atomic bomb was a terrible thing now have no such scruples about it but have transferred their sense of horror to the H-bomb.”19
Lawrence’s specific complaint was with the GAC’s lack of enthusiasm for his proposed giant accelerator. Oppie was not the first to find in Ernest’s latest project a hint of déjà vu. Like the original Calutrons, Lawrence’s MTA would use a stunning amount of outsized machinery to produce, by brute force, an almost infinitesimal yield—perhaps 1 gram of tritium a day. Expressing concern “over possible excessive cost from too ambitious a program,” the GAC had concluded that the project “should not be bulled through, irrespective of cost”—a clear and unmistakable reference to Lawrence and his methods.20
In subsequent meetings, too, Oppenheimer and his colleagues had urged the commission to go slow on the MTA. The AEC likewise favored a more economical approach to achieving what Borden and McMahon were calling “a situation of nuclear plenty”—by increasing the incentives for uranium mining in the American Southwest, for example, and by building more Savannah River–type reactors.21 Pointing out the obvious at one commission meeting, Smyth noted that if Teller’s H-bomb did not work, as seemed the case, there was no need for tritium and no justification for Lawrence’s huge machine.22
That summer, Oppenheimer and the GAC struck at another target close to Teller’s heart. Noting their misgivings “as to the value and relevance” of the upcoming George test, committee members feared that the thermonuclear experiment might interfere with research at Los Alamos into making smaller and more efficient fission weapons. In summary reports to Dean, Oppenheimer argued that the H-bomb model under consideration would likely fizzle and used far too much tritium to be practical, at the same time leaving the “paramount uncertainties” surrounding the Super no closer to resolution.23
Oppenheimer had likewise continued to irritate and embarrass the air force by his advice. Asked by LeBaron to update the 1948 study on long-range military objectives, Oppie’s new panel described the superbomb as “more uncertain and much more difficult of development” than originally believed and, pointedly, a “long range undertaking.”24 The report also put more emphasis upon small, tactical fission weapons—whose development was being hindered by the attention given the Super, Oppie argued.25 Enraged by what he saw as a covert war against the air force’s weapon of choice, Chief of Staff Hoyt Vandenberg ordered Oppenheimer barred from participating in a planned study of strategic targeting.26
* * *
Upon the GAC’s recommendation, the commission decided to withhold funds for Lawrence’s production accelerator, the Mark II, until the prototype machine had been shown to work. Ernest had meanwhile found a site for his Mark I MTA at an abandoned Naval Air Station in Livermore, a verdant valley of farms and vineyards some 40 miles southeast of Berkeley. An Olympic-size swimming pool, once used to train naval aviators in ditching techniques, would provide cooling water for the big machine. High-tension lines that crisscrossed the sere hills, carrying power generated by melting Sierra snows, supplied the electricity. Leftover barracks were pressed into service as offices for scientists and engineers.27
Lawrence had put Alvarez in charge of the MTA. Embracing the project as a surrogate for the ill-fated Benicia Laboratory, Luie imbued it with an enthusiasm that was given added urgency by the Korean invasion. “Anyone who now takes the time to work on mesons is little less than a traitor,” Alvarez reportedly lectured his Rad Lab colleagues.28
Ernest appointed Pief Panofsky the head designer of the machine.29 Lawrence assigned two Rad Lab veterans, Robert Serber and Herbert York, and a relative newcomer—physicist Harold Brown—the task of calculating how many neutrons the MTA would produce.30
But the lab’s focus upon the MTA came at a price: construction of the Bevatron at Berkeley was put on hold. Desks for those assigned to the Livermore project were moved into the building that housed the partially finished machine. Pitzer informed the AEC that, for the foreseeable future, half the Rad Lab’s effort would be devoted to the MTA.31
Like the Calutrons, Lawrence
’s latest machine operated at the far edge of the attainable. The Mark I’s cylindrical tank—nearly 90 feet long, 60 feet wide—was the largest vacuum chamber built thus far. Standard-gauge railroad tracks were laid down its middle to move the MTA’s eighteen massive oscillator tubes, the largest of which weighed 40 tons. The electrical power they required would supply a town of 20,000.32
But the Mark I was lilliputian compared to the planned production machine. The Mark II would require concrete walls some 80 feet high and 20 feet thick for radiation shielding alone, and its appetite for water as well as power far outstripped what was available at Livermore.33 Ernest had scouted out a promising site for the Mark II on the banks of the Missouri River, not far from St. Louis. By late August, he was talking about building up to ten of the mammoth machines in the Midwest. When he encountered resistance to his plans at the AEC, Ernest turned to the Joint Committee.34 His enthusiasm had found a match in Borden’s ambition.
Under pressure from McMahon, the commission gave tentative approval for construction of a single Mark II in September 1950, while the prototype machine was still being built at Livermore.35
But only days after the Mark I was completed that fall, it became clear that the MTA project was already in trouble. The most vexing problem was sparking, caused by dust particles in the cavernous vacuum tank and imperfections in its copper lining.36 Moving cots into the barracks, Alvarez and a colleague began working eighteen-hour shifts: Luie polished the shiny lining while his coworker, crawling out onto a wooden latticework some 30 feet in the air, looked for electrical shorts in the oscillator tubes. Retreating afterward to the control room, the two men held their breath while Alvarez gradually increased the power settings.37
Every spark was accompanied by a bright flash of light from portholes in the side of the vacuum tank and a resounding report. Since the sparking pitted the copper, each discharge made the problem worse. In the ensuing silence and stink of ozone came the dawning realization that the tedious process of polishing and testing had to begin anew.38
Throughout the fall and into the winter, brilliant flashes of artificial lightning lit up Alvarez’s control room while crackling thunder rolled across the former navy base.
* * *
Those whom Lawrence had counted upon in the past to fix the problems with his big machines—the theoretical physicists—were gone; the victims, direct or indirect, of the loyalty oath.
Complaining to Sproul of the “almost complete cessation of scientific work of high quality” as a result of the controversy, Panofsky left Berkeley for Stanford that spring. A last-minute effort by Lawrence and Alvarez to change his mind—they arranged a luncheon at Neylan’s Woodside estate, where the regent proceeded to lecture the diminutive physicist on patriotism—only hastened Panofsky’s departure. Seaborg thought the loss “catastrophic” for the physics department.39
Serber was next to go. Berkeley’s remaining theorist told Lawrence he was leaving for “family reasons” only because the truth was too painful to tell. (“It was whether loyalty to Oppenheimer or loyalty to Ernest Lawrence would prevail,” he said, years later.) “Birge, as you can imagine, is quite broken up at the thought of what is happening to his department—telling him was the hardest part,” the shy physicist wrote to Oppenheimer at Princeton.40
Another Berkeley veteran, Emilio Segrè, had already taken a job at Urbana. Segrè’s complaint was not only the oath, he told Sproul, but the “high-handed position” of Alvarez—who “thinks that all the time of the Department should be spent on war work.”41
Before leaving Berkeley, Segrè had tried to tell Lawrence what Serber and others had been hinting at for months: that the MTA’s sparking problem was essentially unsolvable, given the enormous electrical potential and high vacuum that the MTA required. But Ernest, Segrè later remembered, “reacted with great vehemence, accusing me of being unpatriotic, lazy, selfish, and God knows what more.”42
In a kind of belated victory for the nonsigners, the California courts declared the university’s loyalty oath unconstitutional in April 1951, ordering those who had been fired reinstated. Following Neylan’s resignation as chairman of the Board of Regents that fall, the oath requirement was officially rescinded.43 But the damage had already been done.
Across the Bay, in Livermore, Alvarez soldiered on amid the fearsome thunder of the Mark I. His partner in the control room was relieved to learn that he was being reassigned to another new project at the Rad Lab: preparing the diagnostic measurements for George.44
* * *
At Los Alamos, the war news from Korea had become an almost daily reminder that progress on the Super remained stalled. “The third world war has started and I do not know whether I care to survive it,” Teller wrote to his confidante that winter. Physicist Marshall Holloway, whom Bradbury had made head of the Weapons Division at Los Alamos, had no plans for large-scale thermonuclear tests beyond George. The success or failure of the Cylinder would determine whether future tests along the same line would be worthwhile. But Teller, who was once again back at Los Alamos, on leave from Chicago, wanted Bradbury and Holloway to commit in advance to an ambitious series of tests aimed at producing a superbomb.
As 1951 began, Ulam had been toying with a new idea for what he called “a bomb in a box”—confining an exploding atomic bomb for a fraction of a second in a vessel of dense material, so as to compress the thermonuclear fuel at the other end.45 Key to Ulam’s idea was the notion of focusing the energy from the fission trigger, the “primary,” upon the fusion fuel, the “secondary,” to implode it, thereby dramatically increasing the efficiency of the thermonuclear reaction. In principle, the concept was not unlike the use of high-explosive lenses to implode Fat Man’s plutonium core.
Ulam showed a sketch of his so-called staged bomb to Theoretical Division leader Carson Mark and Bradbury one morning in late January. Mark, preoccupied with last-minute preparations for nuclear tests in Nevada, regarded it as just another candidate for the lab’s thermonuclear “zoo.” Bradbury was only slightly more encouraging.46 But Ulam’s idea received a more welcoming reception from Teller the following day.47
While working on the design of the Cylinder, Teller had been wrestling for months with the question of how radiation flowed from the atomic bomb to the adjoining capsule of tritium and deuterium. Ulam’s sketch inspired Teller to think of another, better way to compress the fusion fuel without heating it—by using radiation from the exploding fission trigger, traveling at the speed of light.48
Heretofore, radiation from the H-bomb’s fission trigger had been the principal problem with the Super; it was what had made Teller’s design appear unworkable. Now it was the solution. Maria Mayer’s work on opacity had finally borne fruit.
Teller had used the words cylindrical implosion to describe what happened in George. A new term—radiation implosion—was coined to describe the phenomenon at work in the Teller-Ulam invention.49
Teller modified and refined the concept over the next several weeks. In early March, he informed Hans Bethe, von Neumann, and Oppenheimer of the modified bomb-in-the-box idea during a meeting at Princeton. All immediately recognized the possibilities. “There are some new thoughts which may be important for you to know,” Oppie wrote Conant in June.50
But Ulam was not nearly as sanguine as Teller that the revolutionary potential of the staged bomb could be exploited anytime soon. The day following the Princeton meeting, Ulam told division leaders at Los Alamos that it might be several years before the lab could incorporate radiation implosion into its weapons. “Edward is full of enthusiasm about these possibilities; this is perhaps an indication they will not work,” Ulam puckishly wrote von Neumann.
Teller, on the other hand, had already begun lobbying for a full-scale test of the concept as soon as possible. Just a few weeks before, citing the lack of progress on the Super, Bradbury had pushed the earliest date for the next series of Pacific tests back another six months.51
Teller’s resentmen
t of Ulam’s role in discrediting the original Super also had not abated.52 On March 9, 1951, Edward published the paper that contained the critical ideas behind the new superbomb: LA-1225, “On Heterocatalytic Detonations I: Hydrodynamic Lenses and Radiation Mirrors.” Although Ulam’s name was on the cover sheet, Teller later would dismiss his coinventor’s contribution as insignificant.53
* * *
By the time preparations for George were under way, Teller was convinced that what he called the “big forces” opposing the superbomb would endeavor to cancel the program if the test of the Cylinder was anything less than a complete success. Lawrence shared his concern.
On May 8, 1951, Ernest rendezvoused with Teller on Eniwetok following the twenty-hour flight from California. Ferried by Piper Cub to the VIP barracks on nearby Parry Island, the two men went swimming in the warm surf that ringed the island. Colleagues whom Edward told of the idea for the staged bomb were surprised to find themselves with goose bumps in the tropic heat.
The next morning, after a delay to allow the weather to clear, Lawrence and Teller joined the admirals, generals, and other VIPs in front of the corrugated tin barracks, where deck chairs had been set up. As at Trinity, Edward had brought suntan lotion as protection from the bomb’s ultraviolet rays. He and Lawrence slipped dark goggles over their eyes when a green flare signaled the five-minute warning.
At 9:30 the Cylinder exploded on Eleleron Island, 16 miles away. In eerie silence, a brilliant white light shone through the gray overcast, spreading quickly across the horizon. From within the familiar mushroom-shaped cloud, the blue-violet light of ionizing radiation shone.
Despite George’s impressive display, the leaden skies made it impossible to know whether the test had been the requisite success. Suspense grew after heavy rains forced the cancellation of the morning’s air-sampling mission. By afternoon, Edward was depressed and anxious, awaiting the results from diagnostic instruments and cameras scattered across the atoll. To ease the tension, Lawrence suggested another swim and offered Teller a wager. Morosely, Edward bet that George had failed.54
