Only a few weeks after the Time cover story, however, the locomotive of adoration was sidelined by a more substantial critique. Its source was none other than Hans Bethe of the Bethe Bible. He had been studying the electrical and magnetic fields of Cornell’s little sixteen-inch cyclotron, which had been built by Livingston in 1935 as the very first non-Berkeley machine. In a letter published in the Physical Review on December 15, Bethe and his associate M. E. Rose declared that the Einsteinian law of relativity placed a hard cap on the cyclotron’s energy at about 11 million volts, which was roughly the rated energy of Berkeley’s thirty-seven-inch accelerator.
Bethe’s reasoning was that as a particle’s mass increased with its velocity, it would reach a point where it would become so massive that it must either become immune to the focusing effects of the magnetic and electrical fields, or its capacity for resonance—that is, reaching the gap between the dees at the exact moment necessary to receive the necessary electrical jolt—must be destroyed. A cyclotron designer could sacrifice either resonance or focusing, but not both. That meant “a very serious difficulty will arise when the attempt is made to accelerate ions . . . to higher energies than obtained thus far.”
Bethe’s stark conclusion that “it seems useless to build cyclotrons of larger proportions than the existing ones” appeared at a delicate and potentially mortifying moment for the Rad Lab. GE’s Coolidge, in his Comstock Prize presentation, had vouched for the vast potential of new and bigger cyclotrons, asserting that “the limit to the particle energies which can be generated in this way is not yet in sight.” Lawrence was beating the bushes for money to build his new 100-volt, sixty-inch cyclotron, which by Bethe’s reckoning was ten times beyond useless. In fact, Bethe declared, thirty-four-inch pole faces were “ample” to reach the relativistic energy limit. That suggested that Berkeley’s thirty-seven-inch machine was already overbuilt.
Yet Lawrence greeted Bethe’s attack with surprising complacency—even condescension. “I am awfully glad that Bethe and Rose are working on the theory of the cyclotron, as it is not a simple problem and the more people think about it the better,” he wrote Lee DuBridge, a Caltech-trained physicist who had become dean of arts and sciences at the University of Rochester. “However, I think it would be well for Bethe not to draw too general conclusions as to what can be done, as there are many ways of skinning a cat.”
Lawrence had several feline pelts already at hand. For one thing, the Rad Lab’s Robert R. Wilson had been studying the shape of the magnetic and electrical focusing fields in the thirty-seven-inch cyclotron, and had found that shaping the dees so that they narrowed toward their outer edges helped focus the beam. Using Wilson’s findings, Ed McMillan calculated that particles could produce a serviceable beam even when they were significantly unfocused and out of resonance. In fact, the cyclotron had been working perfectly well with beams far more defocused by imperfections in the magnetic field—those bothersome irregularities combated by shimming—than they would be by the relativistic effects that Bethe posited. Over the course of an edgy exchange in the pages of the Physical Review, Bethe scoffed at McMillan; McMillan demonstrated the truth of his calculations; and Bethe backed down. Publishing an addendum to his initial paper, he conceded that the true relativistic limit might be double what he originally proposed. Privately, he explained to McMillan that “we considered the existence of a relativistic limit so important that we thought we should communicate it to cyclotronists as quickly as possible, without endeavoring to give accurate figures.”
In truth, there was no doubt that a relativistic limit to cyclotron energies existed; the question was where it was. Stan Livingston had feared that he had hit it as early as 1931. But he had been wrong, and the record of the subsequent seven years suggested that the limit still remained well over the horizon. Hands-on cyclotron operators, a species of which Bethe was not a member, understood that there were so many imponderables about how the machine worked that empirical experience still trumped even the most carefully polished theory. “Although the principle of the cyclotron is simple,” Cockcroft wrote after building a thirty-six-inch accelerator at the Cavendish, “the fact that it works is rather surprising.”
The constraints on the size and power of the cyclotron came from something other than physics. The real limitation, Lawrence advised Mark Oliphant, then planning a sixty-inch machine, was “funds available.” That imposed a constraint Lawrence had become a master at overcoming.
The aplomb with which Lawrence responded to Bethe’s challenge reflected the Rad Lab’s increasing confidence in the quality of its work. Sometimes this was manifested as a new willingness to admit error, as when Niels Bohr visited Berkeley in April 1937 and casually demolished an Oppenheimer theory based on results from the cyclotron.
At issue was an experiment that Lawrence had conducted with James Cork of the University of Michigan on the disintegration of platinum under bombardment. They expected to find that the disintegration yield rose in a curve consonant with increases in the energy of the bombarding deuterons. Instead, they discovered several points at which the yield abruptly jumped out of the curve. Oppenheimer duly contrived “an elegant theory to rationalize these results,” and when Bohr came for his visit, the work was trotted out for him as a showpiece of Rad Lab science.
The presentation took place before a standing-room-only crowd in the LeConte Hall auditorium. Lawrence presented the data, and Oppenheimer followed with a “typically stupefyingly brilliant exposition of its theoretical consequences,” which his hundreds of spectators strained to make out through his “nim-nim-nim” mumbling. Then came Bohr’s turn. His words too were almost inaudible in the cavernous hall, but Lawrence and Oppenheimer were near enough to hear him declare flatly that the results were incompatible with his liquid-drop model of the nucleus, and therefore that Lawrence’s data were invalid and Oppie’s theory nonsensical.
This was a frightful blow, especially as Lawrence’s name was starting to be heard in connection with the Nobel Prize, for which Bohr’s endorsement was indispensable. A few years earlier, Ernest might have dug in his heels as he had at the Solvay Conference, perhaps even suggesting that Bohr’s theory might have to bow to the higher energies achieved by the cyclotron. This time he displayed the maturity to take another look, and had the experimental talent to help him do so. He appointed McMillan and Kamen to ferret out any flaw in the work. They soon discovered that the problem was that old nemesis, contamination. Lawrence and Cork had gone to great lengths, all meticulously documented, to cleanse their platinum targets of all impurities. But their procedure, as it turned out, actually had baked laboratory dust onto the targets, which accounted for the irregular findings.
The next step was to repeat the experiment. This involved months of difficult chemistry to distinguish the various radioactivities from bombarded foils of platinum, iridium, and gold. After all that, McMillan and Kamen still had anomalous results, but of a very different kind. What they discovered were new examples of nuclear isomerism, in which isotopes of identical mass numbers and changes show dramatically different radioactive characteristics. This had been thought to occur only in limited cases, but they showed that the phenomenon was far more widespread than had been known; indeed, they posited a “fantastic number of isomeric nuclei” in their subsequent report to Physical Review. This work held up over time, and the new discovery in his lab provoked by Bohr’s skepticism ultimately enhanced, not diminished, Lawrence’s claim to the Nobel.
Lawrence could also take pride in the cyclotron’s improved reputation as a reliable laboratory instrument. Cockcroft’s judgment notwithstanding, the operational principles of the machine were rapidly becoming standardized. Cooksey witnessed firsthand the conversion of a skeptic into a believer in April 1938, while he was traveling back east on what amounted to a sales mission. Accompanied by Kenneth Bainbridge, a member of the physics faculty at Harvard, he stopped at the Bartol Research Institute, which had completed its cyclotron three month
s earlier. Its builder, Alex Allen, flipped a few switches and produced a beam “at once,” Cooksey reported back to Lawrence. Never having seen a cyclotron in action and having heard tales of its difficult temperament, Bainbridge’s eyes widened. “Why, he just turned it on!” he exclaimed.
Cooksey carried the gospel up the Eastern Seaboard. At Bell Laboratories in New Jersey, he described the machine’s capabilities for Karl Darrow, the lab’s eminent physicist and a writer of popular science articles. Responded Darrow, “I now realize that this country may need a thousand cyclotrons.” That comported nicely with a standard Lawrence proposed to the Cavendish-trained Arthur L. Hughes, who headed the Physics Department at Washington University in St. Louis—that “there should be a cyclotron laboratory in every university center” devoted to nuclear physics, biology, and clinical medicine.
Lawrence could afford to scoff at suggestions that the cyclotron was still in its shakedown stage. During Cooksey’s East Coast tour, physics professor Robley Evans of MIT suggested that his university viewed its cyclotron project, then just getting under way with Stan Livingston in charge, as a sort of probationary test. It was still up to the cyclotron’s inventors, he wrote Cooksey superciliously, to show “whether or not the cyclotron is now a piece of standard equipment, a laboratory tool, which can be put up by your experts in a short time, at reasonable expense, and without undue local development work . . . I rely on receiving from you the necessary personnel, plans, advice etc.” Ernest called MIT’s bluff, informing Evans that he was welcome to hire experienced cyclotroneers from Berkeley to do the job, but warning that the good ones would demand at least an assistant professorship to move.
Evans was not out of line in questioning whether the cyclotron yet ranked as a simple-to-use laboratory apparatus. Following his own ten-day tour of East Coast cyclotrons, Livingston wrote Cooksey fretfully, “Don’t let this get out, but I didn’t find a single cyclotron operating! They were all making changes or in the throes of some development.” Cooksey seconded Livingston’s alarm by scribbling on the letter, “Please do not show this around.”
• • •
As the apostle of building the biggest cyclotrons that technology and funding could produce, Ernest Lawrence was not shy about envisioning the new Berkeley cyclotron being funded by William Crocker’s donation on a grand scale. “For medical purposes alone, such a large installation was hardly justified,” he confided to Arthur Hughes. To Tameichi Yasaki of Tokyo’s Institute for Physical and Chemical Research, which audaciously was building a direct copy of the machine (with Lawrence’s permission) even as the original was rising in Berkeley, he explained that the Crocker was so big “because we can get the money.” In effect, he was saying that there was no virtue in allowing research funding to lie fallow; the cyclotron might be overbuilt for medical research alone, but who could know what wonders that excess power might uncover?
Indeed, the Crocker Cracker was big. Following its magnet’s installation in the new Crocker Laboratory building on campus, Cooksey assembled the entire staff for a photograph to show how big. Thirty-seven men were arranged standing or seated inside the eleven-foot-tall structure. The towering magnet weighed 220 tons, its sixty-inch pole faces nearly twice the diameter of its predecessor’s at the old Rad Lab. One cyclotroneer joked that “its neutrons would reach Chicago”; another wondered, less facetiously, if its beam would be so potent that the targets would be “too hot to handle.”
Ernest now discovered one hazard of overambitious planning: the cost overrun. In the glow of the Harvard offer, he had outlined for Sproul a machine budgeted at $25,000 for construction and $22,000 a year to staff; but the magnet alone turned out to cost $30,000, and the projected staff expenses ballooned in parallel with the expanding ambitions of the research program. By late 1937, the project’s budget had swelled to $75,000 for the building (the sum donated by William Crocker before his death that September) and $68,600 for the cyclotron itself, to be put up by the Chemical Foundation.
And even that was not enough. Ernest shifted his fund-raising efforts into high gear. Fortunately, cyclotrons were still all the rage, especially among biomedical foundations anxious to keep the supply of medical isotopes flowing. A new funding source had entered the field: the National Cancer Institute, established by Congress in August and seeded with $400,000 in annual grant-making authority. Lawrence promptly made an “immediate and urgent” appeal to the director of the National Advisory Cancer Council, the institute’s parent, for $30,000 to equip the Crocker “properly as it should be for clinical and experimental use.” The approval came through in less than two weeks. To Lawrence’s gratification, the council also voted to spend up to $100,000 a year for the next two years to “stimulate” cyclotron-based research into cancer treatment around the country. This task was entrusted to a two-person committee: Arthur Holly Compton of the University of Chicago—a Nobel laureate who was building his own cyclotron with the help of two former Rad Lab men—and Ernest Lawrence, with Compton serving nominally as chair. (“It is not necessary that anyone be named on this committee in addition to you and me,” he assured Lawrence.) Ernest drew up a preliminary list of first-year grants covering almost every cyclotron in the country save his own, apportioning $10,000 each for Chicago, Columbia, Harvard, Michigan, and Princeton.
As it happened, however, the well was about to run dry. The National Advisory Cancer Council reconsidered its decision to scatter its funds in small increments, choosing instead to concentrate its financial firepower on a few larger projects. Meanwhile, the Research Corporation, still smarting from the Depression-related shrinkage of its endowment, began to withdraw funding from programs it considered marginal; under this pressure, Harvard and MIT, neighbors on the banks of the Charles River, took steps to join forces rather than build individual machines. Lawrence’s vision of a cyclotron at every major university, like Darrow’s vision of one thousand machines, looked increasingly fanciful as academic institutions and their patrons began to wonder whether it was healthy for science to be based so heavily on the sheer sums available to support it.
Among the cyclotron labs seeking sustenance, Berkeley remained the most voracious and still the most successful. But Lawrence had to beat every bush. He now made his first appeal to a source he had been carefully nurturing for more than a year. This was the Rockefeller Foundation, which soon would supplant every other source as Ernest Lawrence’s preeminent philanthropic sponsor.
• • •
Ernest Lawrence and Warren Weaver had first met in 1933. Weaver, the director of the Rockefeller Foundation’s Natural Sciences Division, had mapped out an ambitious funding program focusing on experimental biology. Although biomedical research was not yet on the Rad Lab’s agenda, both men filed away the encounter as something to be followed up in the future, in part because they had a common interest in encouraging interdisciplinary research: Weaver, a mathematician who had taught briefly at the small Throop Polytechnic Institute in Pasadena before its transformation into the California Institute of Technology, had as his “special concern” the development of connections “between the biological and the physical sciences (biochemistry, biophysics, chemical genetics, molecular biology, etc.),” as he wrote in a later report to the Rockefeller trustees.
In January 1937, with the Crocker Cracker’s blueprints on the drafting table, Ernest invited Weaver to visit Berkeley. On a bracing afternoon, he escorted Weaver into the Radiation Laboratory and showed him the twenty-seven-inch cyclotron, not skimping on the vaudeville of the lavender deuteron beam shooting into the air. Oddly for someone who had been rubbing shoulders with physicists for nearly twenty years, Weaver mistakenly described the beam in his diary as comprising 5-million-volt “electrons”—particles that were not in the cyclotron’s inventory. (The beam was composed of deuterons, which comprise a proton and a neutron.)
But Weaver did appreciate what was surely the main point urged upon him by his host: “Biology and medicine will have first call on the m
achine.” Lawrence plied him with therapeutic results from his brother’s biomedical research showing that neutrons “are some 5.5 times as effective as X-rays on cancerous tissues, while only about 4.3 times as effective as X-rays in their effect on ordinary tissue,” as Weaver jotted down. “This differential . . . may prove extremely important.” He also recorded Lawrence’s assurance that a recent visitor, “a very distinguished biologist,” had declared “that this technique could well be as important to biology and medicine as the discovery of the microscope.”
Weaver came away dazzled by the cyclotron’s potential as a biomedical tool. Lawrence had laid the groundwork for a request that he finally submitted toward the end of the year. By then, the funding for the sixty-inch cyclotron was running perilously short. The National Cancer Institute’s $30,000 grant had turned out to be insufficient to cover new demands for shielding and other safety provisions. These demands arose from the growing awareness that researchers had become entirely too complacent about the potent electrical and nuclear forces with which they were working. In March a physicist named Wesley Coates—a former doctoral student of Ernest’s—brushed against a high-tension cable in Columbia University’s X-ray lab and received a fatal 5,000-volt shock. The tragedy underscored the necessity of shielding the high voltages at play in the lab.
Even more alarming was what the Lawrence brothers witnessed that September at the Fifth International Congress of Radiology in Chicago. The meeting’s topic was the efficacy of radiation for medical treatments of all kinds, but the impression made on Ernest and John was very different. They could not stop thinking about the men they had met “who had obvious scars on their hands where they’d had skin grafts,” John recalled decades later. “You would shake hands with some man, he’d only have two fingers or something like that, and he might’ve been a famous radiologist.” Ernest’s reaction was uncharacteristically blunt. In a message to Weaver, he called the event a “congress of cripples.”
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