Big Science

by Michael Hiltzik

  Weaver saved the thorniest issue for last. This was the painful question of how the Rad Lab had overlooked so many milestones in nuclear physics during the previous decade: “I suppose that the outstanding developments in the investigation of the nucleus during the last few years would include the discovery of the positron by Anderson in 1932; the discovery of the neutron by . . . Chadwick in 1932; the discovery of the phenomenon of induced radioactivity by Curie and Joliot in 1934; the identification of the mesotron from cosmic ray studies; and the discovery of the phenomenon of nuclear fission by Hahn and others in 1939 . . . Is it not a fact that the five entries I have mentioned are outstanding ones, and that no one [sic] of these discoveries was made using a cyclotron?”

  Unsurprisingly, Lawrence replied in high dudgeon. He disposed of the mesotron question by assuring Weaver that he, Oppenheimer, and Fermi were all agreed that the likely energy of the mesotron was 80 million volts, so that even a 150-inch machine, which he expected to produce projectiles of 100 million volts, should be potent enough to yield the elusive particles.

  As for whether it might be best to let cosmic ray studies play out before building the cyclotron, Lawrence observed that the goal of physics was not merely to “make discoveries of natural phenomena” but to do something with them. This goal could not be met by relying purely on nature’s bounty: “The discovery of the mesotron in cosmic rays will be of little value in the course of time unless there is developed a means of . . . controlling them, and learning of their manifold properties . . . It means a great deal more to civilization, let us say, to find a new radiation or a new substance that will cure disease than it would to discover a super nova.”

  Finally, he turned his attention to Weaver’s irksome list of missed milestones. The simple reason that Berkeley’s cyclotroneers had been beaten to the punch, Lawrence asserted, was that they had remained focused on cyclotron development, in effect, as a service to the future:

  Every one of these discoveries were “in the air” and would have inevitably been made within cyclotron laboratories within certainly a few months. As we were building up the cyclotron beam, we could not possibly have escaped the discovery of artificial radioactivity, for exampel [sic], for more than a month or so after the announcement by Joliot. The development of the cyclotron was begun several years before these discoveries on faith that the availability of controlled atomic projectiles within the laboratory would lead to important scientific progress. If the cyclotron development had been, let us say, a year earlier, I repeat, there is every reason to believe that some of these discoveries referred to would have been made using cyclotrons.

  Lawrence mustered his best arguments for this elaborate defense of his work. But he dodged the truth about several of those discoveries, especially artificial radioactivity and fission: the cyclotroneers had been capable of making them first, had they only tried. It was not the inadequacy of the machine but the Rad Lab’s inattention and its narrow focus that prevented the lab from winning credit for them. Weaver had put his finger on the real shortcoming of the cyclotron lab, which was its scientific judgment, not its technical expertise. That fault could properly be laid to Ernest Lawrence, who was still learning how to balance engineering and hard science.

  Meanwhile, Loomis continued his campaign to secure the grant. He launched a major initiative during the last week of March, when he sponsored a tour of the Rad Lab for a group that functioned as an ad hoc scientific advisory committee for the foundation: both Compton brothers, Karl and Arthur; Harvard president James B. Conant; and Vannevar Bush, president of the Carnegie Institution of Washington.

  Bush was the most important figure in the group for reasons that went beyond his influence with the Rockefeller trustees. A tall, wiry New Englander of fifty, the grandson of Yankee sea captains and the son of a nonconformist Universalist minister, Bush’s upbringing had bequeathed him both a salty independence of mind and a respect for formality and traditional values. Trained as an electrical engineer, in the 1920s he had invented a machine known as a differential analyzer: an analog computer whose digital offspring would dominate the information age. Subsequently he became a vice president at MIT (under Karl Compton) before taking up the Carnegie presidency, a position that placed him at the crossroads of government policy and academic research. He was already thinking about the role America’s scientists might play in the world war lurking on the horizon. For a year, Bush had been meeting regularly with Conant, Karl Compton, and other leading science administrators to show concern about the country’s listless response to a crisis that might easily spread beyond European borders and to ponder the imperative of technological preparedness. “We were agreed,” he wrote later, “that the war was bound to break out into an intense struggle, that America was sure to get into it one way or another sooner or later, that it would be a highly technical struggle, that we were by no means prepared in this regard.” He was determined to have a hand in moving the country’s technical establishment into the forefront of wartime planning. Now, meeting Lawrence in person for the first time, he found himself agreeing with Loomis that the Berkeley physicist should be part of the effort.

  Guided along the Rad Lab’s corridors by Loomis and Lawrence, the visitors stopped briefly in Don Cooksey’s second-floor office. Seated at ease in three-piece suits under a blackboard displaying the dees of a simple cyclotron, they allowed Cooksey to snap a photograph of them grinning companionably at one another as though in shared appreciation of an inside joke. The snapshot was fated to become a historical artifact, for within a year, these same men would come together again—as leaders of America’s effort to create the atomic bomb.

  The tour of Berkeley would play a critical role in allowing men acquainted chiefly as professional colleagues to take one another’s measure as individuals. The process was helped along by a party Loomis threw that weekend at the Del Monte Lodge in Monterey, a few hours down the coast from Berkeley. His goal was to expose them at close quarters to the charismatic energy of his protégé Ernest Lawrence, and he was surely successful at finalizing their approval for the cyclotron grant. “You can’t get a group together for a long weekend without Ernest’s effect on them,” he reflected later. By the end of the weekend, “there was no opposition.” The advisory committee transmitted its unanimous endorsement of the 184-inch machine to the foundation before leaving the West Coast. Weaver and Loomis put the finishing touches on the lobbying effort by persuading Fosdick that the cyclotron would stand as a bookend with the foundation’s other great scientific investment: the 200-inch Hale telescope planned for Mount Palomar in Southern California, cementing the Rockefeller Foundation’s stature as the world’s preeminent supporter of Big Science.

  On the morning of April 3, Lawrence picked up the phone at the Rad Lab to hear Weaver’s voice on the other end. “Our trustees voted $1,150,000,” he said. With the $250,000 in operating costs that Sproul had managed to pry from the Berkeley regents, that essentially provided everything Lawrence had requested.

  “The full original budget,” Ernest marveled over the long-distance line. “It’s hard to tell you how I feel.”

  To Poillon he showed less reticence, declaring himself to be “walking on air.” The money was a landmark, for no single research laboratory had ever received a grant of such magnitude; none even had shown the audacity to ask. But it was not only the money, it was the public expression of esteem from the leading figures in science and business, delivered via a unanimous vote by nineteen distinguished representatives of industry and academia sitting as the Rockefeller Foundation board. The era of Big Science was now launched by a partnership of foundation, university, and industry. And it had all happened without a single dissenting vote. “Great and small, they all backed the plan and you,” Dave Morris wrote Lawrence the next day. “Do get full emotional satisfaction from such rare unanimity: You deserve it.”

  In the weeks following the board’s approval, Loomis continued to place himself at the service of the 184-in
ch cyclotron. Bringing Lawrence back to New York, he exploited his personal business contacts to secure tons of copper and iron for the giant machine. War preparations were already tightening the supplies of both commodities, but Loomis pulled strings, even yanked them, to get Lawrence what he needed at a preferential price. As Ernest related to Alvarez, “After spending some time with the Guggenheims, during which a favorable price for copper was negotiated, Alfred said, ‘Well, now we have to go after the iron. I think Ed Stettinius is the right man.’ ” A call was duly placed to the chairman of the United States Steel Corporation: “Hello, Ed, this is Alfred. I have someone with me I think you’d like to meet. When can we come over?”

  But there were some things that Loomis could not control. The Rockefeller Foundation grant required the cyclotron to be completed and placed in operation by June 30, 1944. For understandable reasons, it would fail to meet that deadline.

  Part Three

  * * *

  THE BOMBS

  Chapter Eleven

  * * *

  “Ernest, Are You Ready?”

  “It was a cool September evening.” Arthur Holly Compton serenely begins his account of his meeting with Ernest Lawrence and James B. Conant, the president of Harvard University, in Chicago on September 25, 1941. “My wife greeted Conant and Lawrence as they came into our home and gave each of us a cup of coffee as we gathered around the fireplace. Then she busied herself upstairs so the three of us might talk freely.”

  Compton’s guests had come to the city to receive honorary doctorates from the University of Chicago. But that only provided the opportunity for this more momentous encounter, which had much to do with Conant’s role as an important science advisor to the Roosevelt administration and Compton’s as head of a blue-ribbon committee charged with appraising the military usefulness of atomic energy. Lawrence, who had demanded the urgent face-to-face meeting, had come bearing news of an extraordinary breakthrough in that field. Their conversation took scarcely more than an hour. But when it was over, America’s wartime planning, and the lives of all three men, had been set on a new course. The country was on its way to building the atomic bomb.

  • • •

  The roots of the meeting had been planted more than two years earlier by the discovery of nuclear fission. That news, which broke in January 1939, launched physicists upon flights of learned speculation about the enormous energy released when the uranium nucleus split following its absorption of a stray neutron. Most intriguing was the possibility of a chain reaction: if neutrons emitted in fission struck neighboring nuclei and caused them to split, they might in turn emit even more neutrons, producing more fissions. If enough neutrons boiled out of each shattered nucleus with just the right energy, the process might continue on its own until no more uranium nuclei remained to shatter.

  Whether this process would produce explosions or merely heat became the focus of a rather abstract debate, for the practicalities of harnessing the energy were elusive. As befit the man who had challenged Ernest Rutherford’s disparagement of atomic power as “moonshine” back in 1933, Ernest Lawrence’s first instinct was to take the news of fission as vindication. “It may be that the day of useful nuclear energy is not so far distant after all,” he wrote to his fellow cyclotron builder Alexander Allen.

  Among those who let their imaginations roam was Robert Oppenheimer. When Luis Alvarez burst in on his seminar with news of the first report of fission’s discovery by Otto Hahn and Fritz Strassmann, Oppenheimer had responded instantly, “That’s impossible.” But within hours, he had withdrawn his snap judgment. And within a week, recalled one of his students, he had filled his office blackboard in LeConte Hall with “a drawing—very bad, an execrable drawing—of a bomb.”

  Oppie shared his conjectures widely. “In how many ways does the U come apart?” he wrote a fellow physicist. “At random, as one might guess, or only in certain ways? And most of all, are there many neutrons that come off during the splitting, or from the excited pieces? . . . [S]hould be quite something.” To another, he expanded on the theme with a sort of minatory thrill: “I think it really not too improbable that a ten cm cube of uranium deuteride . . . might very well blow itself to hell.”

  One man who took such apocalyptic speculation seriously was Leo Szilard, the energetic and resourceful Hungarian physicist who had tried to patent a prototypical cyclotron just before Lawrence’s practical invention. Szilard was tormented by a vision of uranium’s explosive potential placed in the hands of Adolf Hitler. “You know what that means?” he told Edward Teller, a fellow Hungarian émigré. “Hitler’s success could depend on it.” Szilard urged his colleagues to verify the explosiveness of the reaction promptly, the better to steal a march on any German research that might soon get under way, and to place their research results voluntarily under wraps. But his promptings about secrecy fell largely on deaf ears, due in part to widespread skepticism that there was anything worth concealing. To Szilard’s friend Enrico Fermi, the possibility of an explosive reaction was so remote that Szilard’s concerns seemed driven by paranoia, not physics.

  Yet Szilard had learned from bitter experience that sometimes paranoia is the prudent approach. In 1933, when Hitler came to power and he was a junior instructor living at the faculty club of the Kaiser Wilhelm Institute of Physics in Berlin, he had kept two suitcases packed in his rooms. When the Reichstag building burned down, which became the pretext for Hitler’s suppression of political dissent, Szilard was dismayed by the failure of his German friends to grasp the developing reality. “They all thought that civilized Germans would not stand for anything really rough.” The day after the fire, he fled to Vienna on a nearly empty train; one day after that, he would learn, all Austria-bound trains were jammed with would-be refugees, who were stopped and interrogated at the border. “This just goes to show,” Szilard wrote, “that if you want to succeed in this world, you don’t have to be much cleverer than other people, you just have to be one day earlier than most people.”

  Szilard was determined that scientists in America should have that oneday advantage. It would be a source of anguished frustration to him that his warnings met with complacency, especially from fellow refugees such as Fermi, who should have been far more sensitive to the peril of being late. “We both wanted to be conservative, but Fermi thought that the conservative thing was to play down the possibility that this [chain reaction] might happen, and I thought the conservative thing was to assume that it would happen and take all the necessary precautions.”

  Physicists at the Radiation Laboratory and elsewhere picked away at the secrets of uranium fission all that year, trying to answer Oppenheimer’s questions as well as others more fundamental. What triggered the reaction? Why was it not seen in uranium in its natural state? The fact that uranium deposits occurred naturally around the world without disintegrating themselves suggested that extraordinary conditions had to be present.

  It was Niels Bohr who came up with the crucial insight. Natural uranium’s fission cross section—that is, the probability that the nucleus would fission under given circumstances—was highly sensitive to the energy of the impinging neutrons. The explanation, Bohr recognized, lay in the prevalence of distinct uranium isotopes. The most abundant isotope, U-238, was harder to nudge toward fission than to move a recalcitrant donkey, and it responded only to fast, or highly energetic, neutrons. But naturally occurring uranium also contained U-235, which was much more fissile—highly likely to split after absorbing a neutron of almost any speed. U-235, however, was present only in the tiny ratio of 1 atom in 139, or about 0.7 percent.

  Bohr’s insight motivated physicists to ask whether fissioning concentrated U-235 would produce the abundant neutrons needed to sustain a chain reaction, and if so, how could one separate U-235 from U-238 or increase its prevalence in a sample? Since isotopes are chemically identical, a nonchemical means had to be found to accomplish this. The neutrons produced from the fissioning nucleus, known as secondary neutrons, �
�became the object of a worldwide search,” Luis Alvarez recalled.

  Everywhere in the world, curiously, except the Rad Lab. Lawrence judged that the glory that might come from being the first to discover secondary neutrons was not worth delaying the completion of the sixty-inch cyclotron, which was needed to meet the increasing demand for medical isotopes. The task of finding fission neutrons was dumped in the lap of Alvarez, then a junior researcher still searching for a career-making project. He did not see the task as a ticket to fame, so he designed what he called a “quickie experiment” involving a single neutron detector placed in a stairway outside the cyclotron room. He spent all of five minutes bombarding uranium oxide, and, detecting no neutrons in his apparatus, gave up. Only later did he realize that if he had moved his counter a bit nearer the cyclotron, bombarded a bit more uranium, and counted for an hour instead of five minutes, he would have found that very day the secondary neutrons being sought all over the world.

  Joliot’s team accomplished that task in March, estimating the yield of secondary neutrons from U-235 at about 3.5 neutrons per uranium fission. Szilard and Fermi, working in separate labs at Columbia University, came up with a figure closer to 2.0—still a large quantity under the circumstances. “Chances for reaction now above 50%,” Szilard wired a friend. He felt no triumph in the discovery, though, recalling later: “That night, there was very little doubt in my mind that the world was headed for grief.”