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  Chapter Four

  * * *

  Shims and Sealing Wax

  Livingston’s breakthrough did not conclude the effort to improve the eleven-inch cyclotron’s performance. Over the following months, he and Ernest sweated to produce an even more energetic particle beam. This involved long hours, late into the night, with barely any respite. Every component of the machine was disassembled, rebuilt, and reassembled, under the impetus to reach a new voltage threshold. “We were heading for something big, definitely,” Livingston remembered. “Lawrence said, ‘We’re making history.’ He wouldn’t let me take a minute’s time off for anything else.” Livingston, habitually a gloomy personality, was beginning to chafe under his mentor’s relentless prodding. But Ernest’s extroverted enthusiasm and the opportunity to be in on a groundbreaking discovery carried him along, for the moment.

  After Ernest returned from the East and examined Livingston’s grid-free dees, he realized that allowing the electrical field to leak into the dees actually focused the particle beam, thereby protecting the spiraling protons from obliterating collisions with the walls of the vacuum chamber. He explained the phenomenon to a surprised Livingston by sketching the lines of electrical force on a blackboard. “It was Lawrence’s genius for understanding a new phenomenon when he had only a glimpse of it,” Livingston marveled years later. Livingston had discovered electrical focusing by sheer ingenuity and serendipity; Lawrence recognized the underlying principle, which enabled him to incorporate it into subsequent designs.

  Livingston also was perplexed about his inability to coax the protons to more than seventy-five accelerating steps, a mysterious constraint on the machine’s effectiveness. He suspected that the obstacle was the relativistic limit predicted by Einstein’s theories: as a particle gained velocity, it also increased in mass, which eventually destroyed its ability to remain synchronized with the oscillating electrical field. If that were so, the reign of the cyclotron as science’s most powerful and effective atom smasher might be a brief one. Lawrence acknowledged the presence of some obstacle, but instinct told him they were nowhere near the relativistic limit. Instead, he concluded, irregularities in the magnetic field were driving the proton beam out of resonance. The solution he and Livingston invented was to insert strips of metal, or shims, at certain points in the gaps between the vacuum chamber and the magnet poles to compensate for those irregularities and “shape” the field.

  Whether it was Lawrence or Livingston who first came up with shimming is unknown, for both would claim credit. But they spent long hours together testing different shapes, sizes, and placements of the shims in an endless process of cut and try: randomly inserting circles, squares, rings, polyhedrons of metal in the gap, like auto mechanics trying to balance a wheel with lead weights by sight. Eventually they discovered that an elongated teardrop shape, with the wide end oriented toward the magnet’s center, quadrupled the maximum potential acceleration to 300 steps, or 150 complete circuits. This milestone was reached on January 9, 1932, when they placed 4,000 volts on the dees and, after 300 kicks, ended up with protons at 1.22 million volts. “Here again, experiment preceded theory!” Lawrence declared. His exuberance almost matched the moment when he had hatched the cyclotron idea itself. “As the galvanometer spot swung across the scale, indicating that protons of 1-MeV energy were reaching the collector,” Livingston recalled, “Lawrence literally danced around the room with glee.”

  News of the discovery spread campus-wide. “We were busy all that day demonstrating million-volt protons to eager viewers,” Livingston recalled, leaving it unsaid that what the visitors witnessed was only indirect evidence of the achievement—a needle swinging from one end to the other on an electrical meter. The news created a sensation off campus, too, with stories in all the local newspapers and not a few national publications, reinforcing the impression taking hold in the international physics community that something exceptional was happening in this former backwater on the West Coast. The very day before Lawrence and Livingston breached 1 million volts, the Princeton physicist Joseph Boyce had reported to his colleagues: “The place on the coast where things are really going on is Berkeley. Lawrence is just moving into an old wooden building . . . where he hopes to have six different high-speed particle outfits.” He mentioned the eleven-inch, the new twenty-seven-inch accelerator soon to make use of the Federal Telegraph magnet, Sloan’s linear accelerator for heavy ions, a Tesla coil, and a Van de Graaff generator (which was never actually erected, though a room was reserved for it). “On paper,” Boyce continued, “this sounds like a wild damn fool program, but Lawrence is a very able director, has many graduate students, adequate financial backing, and in his work so far with protons and mercury ions has achieved sufficient success to justify great confidence in his future.” The building blocks of Big Science were being moved into place.

  But the euphoria proved to be short lived. In late April word arrived of another striking achievement from the tatty corridors of the Cavendish: physicist John Douglas Cockcroft, working with a young graduate of Dublin’s Trinity College named Ernest Walton, had disintegrated a lithium nucleus by bombarding it with protons at energies a fraction of those Lawrence had achieved, and a fraction of those Lawrence thought necessary to do the job. Lawrence had invented a superb instrument for smashing atoms, but while he was preoccupied with making the tool better, the quintessential small-science lab had stolen the prize from under his nose.

  Cockcroft was thirty-four, a man with the mild eccentricities that American physicists had come to expect in their cross-oceanic colleagues. He was so intensely devoted to experimental physics that even his laboratory fellows considered him hopelessly aloof: “To a superficial acquaintance like myself,” remembered a Cambridge experimentalist, “it appeared that when the ice had broken, a lot of cold water would be found underneath.” But Cockcroft was a thoughtful physicist in the style treasured by Rutherford, especially in his resourcefulness with equipment, the Cavendish’s hallmark. It was Rutherford who had assigned Cockcroft the task of splitting the atom and personally paired him with Walton.

  Cockcroft’s approach differed diametrically from Lawrence’s. Instead of producing beams with high energies but a low current like the cyclotron’s—that is, protons that were speedy but few in number—his goal was to produce protons with moderate energies but in great profusion. This method derived from the theories of the Russian physicist George Gamow, who deduced from quantum mechanics that the occasional particle from even a moderately energetic beam could penetrate the nucleus. Produce protons in sufficient quantity, Gamow suggested, and sooner or later a lucky bullet would find its mark.

  Cockcroft and Walton aimed to generate a mere 300,000 volts, which they considered attainable with an array of electrical capacitors that would charge up in series and discharge in parallel, like a giant weight winched up in steps and then dropped abruptly to the ground. Their voltage multiplier was arranged as several vertical tubes in an upper story of the Cavendish, with the main accelerator tube inserted through a hole drilled in the floor and terminating in a wooden hutch in the basement. The experimenter folded himself into that cramped space and fixed his eye on a scintillation screen capturing flashes from a bombarded lithium target. On April 16 Cockcroft and Walton nervously summoned Rutherford to the basement so he might see for himself a scintillation pattern they thought heavily suggestive of alpha particles. After a few minutes of viewing, the discoverer of alpha rays crawled from the hutch and declared, “I know an alpha when I see one.” The conclusion was inescapable: Cockcroft and Walton had fired a proton into lithium, which in its most common form has a nucleus of three protons and four neutrons. The yield was two alpha particles, each with two protons and two neutrons.

  More than a decade earlier, Rutherford had fired an alpha particle at nitrogen and knocked a proton free; his associates had attempted the converse by firing a proton at lithium, and for the first time had split the atom. It was another instance, and not th
e last, of Cavendish intuition and resourcefulness outplaying labs with more soaring ambitions, superior resources, and, perhaps, a touch less vision.

  Lawrence declared himself pleased for his fellow inventors. But plainly he was rankled at having been outmaneuvered on a quest so easily within reach. “We weren’t ready for experiments yet,” Livingston recalled mournfully. “I had built the machine but had not included any devices for studying disintegrations.”

  Lawrence moved rapidly to recover from the defeat, albeit at long range. He had wed Molly Blumer on the Yale campus on May 14, a day before her twenty-first birthday and only a few days after the Cockcroft-Walton report reached the United States in the pages of the journal Nature. From his honeymoon cabin on Long Island Sound, he wired his graduate student Jim Brady to help Livingston bombard a lithium crystal in the eleven-inch accelerator. Brady had earned his PhD and already accepted a faculty post at Saint Louis University. But Lawrence artfully persuaded Brady’s new dean to let him stay on at Berkeley through the summer to acquire a last layer of polish while collecting his first paychecks from Saint Louis—a canny arrangement that gave the Rad Lab an extra pair of hands, courtesy of the SLU budget. Eager to jump into what was now the hottest line of research in nuclear physics, Brady checked out a lump of lithium from the Chemistry Department storeroom. Two of Lawrence’s friends visiting from Yale for the summer, Don Cooksey and Franz Kurie, offered to help, and since Cooksey also possessed an expertise in hand-manufacturing Geiger counters, Brady readily accepted.

  While the Rad Lab staff worked at reproducing the Cockcroft-Walton results, the newlyweds made their circuitous way back to California, visiting with friends in New York and Chicago and eventually stopping at the Lawrence family homestead in Canton. There Molly came face-to-face with the difference in lifestyles between the cosmopolitan Blumers of New Haven and the Lawrences of pastoral Canton. When she pulled out an after-dinner cigarette, a habit unremarked in the Blumer household, the scandalized Gunda Lawrence hastily drew the window shades, lest her neighbors remark on the sight of a woman smoking in her home. Carl joined Molly with a cigar, meeting his wife’s scowl with his customary defense, “Everyone has to have some bad habit.”

  Ernest and Molly moved into a rented house on Berkeley’s Keith Avenue, in a hilly neighborhood just north of the campus. Brady had decamped for his own wedding and his new post in St. Louis; Cooksey and Kurie had returned East. The lithium experiment was in the hands of a graduate student named Milton White, who now got his first exposure to Ernest Lawrence in the throes of a mania.

  “The place was beginning at this point to catch fire,” White would recall. Lawrence was already occupied with the twenty-seven-inch cyclotron rising in the wooden Rad Lab. But he would appear every day in LeConte Hall, sometimes late at night, to peer over White’s shoulder and pore over his results. “He’d come in at two or three in the morning wanting to know why we hadn’t gotten more data, what’s holding us back, and he was really putting the pressure on.” Adding to the tension was what White perceived as “a certain amount of shamefacedness that we hadn’t been the first” to disintegrate a nucleus—the more so because the overlooked pieces of the Rad Lab system had been those easiest to design, the counters and detectors. The accelerator was the harder technology, yet that they had mastered. Had the lab paused to direct itself at this obvious experimental goal, it would have been the first to disintegrate lithium, not a sheepish second.

  The prickliness of the machine’s behavior did not help anyone’s mood. The eleven-inch accelerator’s magnet, which was not water cooled as the new magnet would be, could run for only about an hour at maximum energy before overheating. Then it needed thirteen hours to cool down fully. White would run the machine for the permitted hour starting at one in the afternoon, and then power down, returning for another hourlong run at three in the morning. The process would resume at five o’clock the next afternoon. Beleaguered by sleeplessness, White staggered around campus like a zombie, not knowing day from night.

  Still, once yoked to a concrete experimental goal, the eleven-inch proved itself worthy of the task. After only three weeks of bombardments under Lawrence’s intent gaze, White had enough data to publish. The Rad Lab’s letter reporting its own disintegrations of lithium went out to the journal Physical Review on September 15 and appeared in print two weeks later over the names of Lawrence, Livingston, and White. Their report downplayed the fact that they had not really broken new ground but largely had confirmed the Cockcroft-Walton discovery; but they did emphasize that by doubling the Cavendish’s energy levels, they had shown that the emission of alpha particles continued to increase with the energy of the bombarding protons, a not-inconsiderable extension of the Cavendish results.

  • • •

  Lawrence’s move into the wood clapboard Rad Lab in 1932 marked an administrative, financial, and intellectual break between the lab and the Berkeley Physics Department, its putative parent. The gulf would only grow wider as his stature rose. Raymond Birge, who became department chairman upon Elmer Hall’s passing that same year, was fond of remarking with a wry jocularity, “I don’t know what goes on over there in that Radiation Lab.” Still, he retained a deserved sense of pride in having brought Lawrence to Berkeley in the first place.

  The most obvious sign of the difference between the Physics Department and the Rad Lab was the divergence in their research budgets. The department’s budget from 1931 through 1933 averaged about $11,000 a year, mostly for apparatus and supplies, falling to $8,000 in the Depression year of 1934. By contrast, the Rad Lab’s spending kept rising—from $17,670 in 1933 to $22,000 in 1936. Those figures did not count the salaries of Lawrence ($5,000 in 1932) and Donald Cooksey, who emigrated from Yale in 1932 to become functionally (if not yet formally) the lab’s associate director, at $3,000. Their pay was billed to the departmental budget, as were teaching assistantships and other small stipends paid out to the platoon of graduate fellows who were now tending, in shifts, the cyclotron humming away on the new Rad Lab’s ground floor.

  Lawrence exploited to the limit the free labor of graduate students, an important key to low-cost operation of the enormous piece of capital equipment he was erecting. In 1937, a typical year, the Rad Lab listed seventeen postdoctoral physics fellows on its staff but paid the salaries of only two. The others were sustained on stipends from donors such as the National Research Council and the Rockefeller Foundation, or were paid out of unallocated grants made to the Rad Lab by the same bodies. Lawrence’s ability to run a program costing tens of thousands of dollars by juggling contributions from a dozen sources made the Rad Lab virtually immune to the Depression-related budget cuts afflicting every other part of the university. From 1932 through 1939, the lab’s overall staff shot up from ten to sixty, but the number of Rad Lab personnel paid out of state funds never exceeded ten. After 1933, Lawrence even tapped federal New Deal programs such as the Works Progress Administration and the National Youth Authority, which supported as many as fifteen researchers a year.

  From this raw material, Lawrence was creating a cohesive research organization. His genial personality provided some of the glue, but so did his single-minded devotion to improving the accelerator and his receptiveness to all varieties of scientific contribution; the Rad Lab was soon populated with chemists, biologists, medical scientists, and engineers in what was, for academic institutions of the time, a uniquely interdisciplinary atmosphere.

  The give-and-take of scientific discussion was fostered by another Lawrence innovation: the Journal Club, a weekly colloquium to which all the Rad Lab staff and visitors from other departments were invited. Every Monday evening at seven thirty sharp, the accelerators were turned off and the staff convened in the LeConte Hall library. Ernest managed the agenda, which he did not announce in advance, from a big red leather chair. The evening’s speaker might be a graduate student assigned to explicate a recent paper from Europe, or a visiting luminary discussing his own work. The Journal Club prov
ed to be an ideal way to keep the lab abreast of the latest advances in physics, but over time the agenda reflected the lab’s own expanding prominence. At its inception, the topics for discussion almost always concerned research done elsewhere; by 1936, they almost always concerned research carried out at Berkeley.

  • • •

  Meanwhile, the wealthy and influential personages of Northern California, many of whom had been educated at Berkeley and supported the university generously, began to eye a new, high-profile candidate for their philanthropy. Bay Area industry began to perceive the value of a relationship with Lawrence and his increasingly famous machine. To obtain radio tubes for David Sloan’s X-ray machine, Lawrence appealed to Federal Telegraph, which allowed itself to be bargained down to a steeply discounted price of $225 per tube, deducting the discount as a charitable contribution. Only a few commercial enterprises showed the fortitude to resist Ernest’s importuning. One was the giant utility Pacific Gas and Electric Company. Asked in September 1931 to donate 120,000 kilowatt-hours to run the cyclotron for a year, the company’s president, August F. Hockenblamer, took a firm line. “This company is the second largest taxpayer in the state of California and as such contributes very largely to the funds of the university,” he lectured Berkeley’s research dean, A. O. Leuschner. “It seems to me the cost of experiments coming in the category of ‘pure science’ ought to come out of the funds of the university.” PG&E was willing to put up extra money for research it might be able to exploit commercially, such as studies of “the utilization of electricity on the farm,” he wrote. The cyclotron did not qualify.