IF WASHINGTON FAILED to perceive the importance of an atomic bomb early in the war, London did not. British scientists were furiously studying the feasibility of a bomb, their motivation simple and urgent: to beat Hitler to the punch. This was crucial, for by mid-June 1940 France had fallen to the Nazis. Britain now stood alone, and many people feared that Germany would soon cross the English Channel. The notion that Hitler was ahead in the atomic race had become so deep-rooted that it was treated as a certainty. “We were told day in and day out that it was our duty to catch up with the Germans,” recalled a British physicist. 1 In 1940 it was still difficult for Americans to think about the war, while it was the only concern for the British.
The principles of fission and a chain reaction were clear enough to British scientists by 1940. Far less clear to them was the feasibility and expense of separating U-235 and constructing a weapon in time to be useful. Three questions overshadowed all others: How could a sufficient amount of fissionable material be collected? How much material would constitute the critical mass necessary to sustain a chain reaction? And how could the material be assembled rapidly enough so that it exploded, rather than simply fizzled like a pile of gunpowder?
The advanced state of British efforts and the desperate need to work quickly combined to effectively override whatever bureaucratic obstacles might normally have interfered with fission research. The imperative of survival concentrated British scientific minds dramatically.
Two of them, refugees Rudolf Peierls and Otto Frisch—the latter for the second time playing a decisive role—got together in early March 1940 to discuss the implications of fission. Peierls remembered: “I had a conversation with Frisch in the course of which he asked, ‘Well, Bohr and Wheeler have made it quite clear that the fission is due to 235. What would happen if one had a pure uranium 235 in a sufficient quantity? How much would you need? And if you got it, what would happen?’” 2
Frisch and Peierls came up with startling answers to these questions. Early estimates of the “critical mass,” the amount of U-235 needed to start a chain reaction, had run to several tons—far too much for a deliverable weapon. But Frisch and Peierls produced an estimate that only one kilogram (just over two pounds) of U-235 could create a critical mass that would explode with a force equivalent to that of several thousand tons of dynamite. Eighty generations of neutrons would multiply in millionths of a second, yielding temperatures as hot as the interior of the sun and as deadly in radiation, before the swelling explosion separated the atoms of U-235 enough to stop the chain reaction.
“Our first reaction was to realize that this was no longer an academic exercise, but a highly practical problem, in spite of the almost science-fiction nature of large-scale isotope separation,” Peierls recalled later. “Then it struck us that, as the idea had come to us so easily, it was likely to have occurred to the Germans, and the thought of such a weapon in Nazi hands was frightening.” 3 Something had to be done immediately. They decided to draw the attention of the authorities to this possibility and its implications. In a three-page memorandum, they described their calculations and a practical mechanism for a bomb: making a U-235 sphere in two parts “which are brought together when the explosion is wanted.” As soon as the hemispheres touched, the whole assembly “would explode within a second or less.” The yield would be immense. Lethal radiation would be emitted on a large scale, against which “effective protection is hardly possible.” 4
“I have often been asked,” Frisch wrote years afterward, “why I didn’t abandon the project there and then, saying nothing to anybody. Why start on a project that, if it was successful, would end with the production of a weapon of unparalleled violence, a weapon of mass destruction such as the world had never seen? The answer was very simple. We were at war, and the idea was reasonably obvious; very probably some German scientists had had the same idea and were working on it.” 5
The Frisch-Peierls memorandum consisted of not more than a thousand words, but it was all there. They not only asked the right questions, they also answered them. They made isotope separation sound simpler than it proved to be, and their estimate of the quantity of U-235 needed was too low, but these errors only increased official attention to and acceptance of their analysis. An atomic bomb had seemed like science fiction to government officials. Now it seemed feasible. 6
Otto Frisch was an Austrian, and Rudolf Peierls was a German. They should have been making their pioneering calculations at the Kaiser Wilhelm Institute in Berlin. But instead they made them at the University of Birmingham, in England. The reason for their relocation was simple: they were Jews.
British authorities referred their paper to a scientific committee code-named MAUD. Over the next fifteen months—through the successive shocks of the invasion of Norway, the fall of France, the Battle of Britain, the London Blitz, the fall of Yugoslavia and Greece, and the attack on the Soviet Union—the MAUD Committee carefully reviewed the two refugee physicists’ conclusions. By the middle of 1941 their conclusions had persuaded London to undertake an atomic bomb program. The MAUD Committee recommended “that this work be continued on the highest priority and on the increasing scale necessary to obtain the weapon in the shortest possible time.” 7
The British government preferred to keep the whole project (and thus its control) in the United Kingdom, but it would require an immense industrial effort. It was one thing to talk of separating U-235 isotopes on this scale, but a formidable job to do it. The country was at war and was struggling to survive, which meant that its scientific talent and resources had to be devoted to projects with immediate practical military value—like radar. Britain’s ally, America, on the other hand, was still not in the war and possessed vast industrial resources. The British government decided to go ahead as fast as possible with research, and then—if the work was promising—to persuade the United States to build a production plant for the bomb. London understood what this would mean down the road: Washington, by contributing the majority of technical and industrial effort, would effectively control the bomb. But London had little choice; such an effort in Britain was impossible because of the strain on British resources and the danger to British project sites from German bombing. Hence, it was decided to lobby the Americans.
As part of its lobbying effort, the British government dispatched an Australian physicist working at the University of Birmingham with Frisch and Peierls named Mark Oliphant across the Atlantic in the late summer of 1941 to proselytize for an atomic bomb. His mission was to stir American physicists to action. “If Congress knew the true history of the atomic energy project,” Leo Szilard said modestly after the war, “I have no doubt but that it would create a special medal to be given to meddling foreigners for distinguished services, and Dr. Oliphant would be the first to receive one.” 8 Oliphant was a blunt, forceful, and persuasive man who was chosen by the British government to seek out one American physicist in particular, a striver of immense self-confidence and practical genius named Ernest Lawrence.
A tall, broad-shouldered man with slicked-back strawberry blond hair atop a boyish face colored by pale blue eyes set behind rimless glasses, Lawrence was a talented gadgeteer and charming yet shrewd promoter from the prairie heartland of America. There was something enormously vital in his movements, in the energetic way he walked and talked. He moved so quickly that he always seemed to be on the run. He was not a brilliant physicist, but he loved to build great big powerful machines, and his enormous drive got them built.
Born in South Dakota in 1901, Lawrence inherited his drive from his father, Carl, a small-town Babbitt who built a big house, became a leading citizen, and constantly kept his eye out for the main chance. His son showed a similar knack from the time he was in college at the University of South Dakota. He was so enthusiastic and persuasive in his request to the dean of students for funds to buy radio equipment that the dean gave him the money on the spot and urged him to take up the study of physics. He told Lawrence about another country boy named Ernest from New Zealand (Rutherford), who had won the Nobel Prize for his insights into atomic structure. What adventure could equal that of searching for nature’s secrets? he said, firing the young man’s imagination. Who knew what might be discovered next?
After college Lawrence attended graduate school at the University of Chicago, where he came into contact with Arthur Compton, and later moved to Yale. He developed beautiful technique as an experimenter, with not only remarkable physical intuition but also the confidence to believe in his instincts. While at Yale, he invented the “cyclotron,” an atom smasher that provided an entirely new way of studying the nucleus. His first cyclotron was a bellows-shaped glass instrument just four inches wide and covered with red sealing wax against vacuum leaks. It worked by accelerating electrically charged particles in a magnetic field and then aiming them at a target. The subatomic pieces that broke off on impact provided clues to the internal structure of the atom. The cyclotron quickly earned Lawrence what he wanted most: publicly acknowledged success. He became the boy wonder of American science.
The University of California, Berkeley, which sought to build up its physics department, wooed Lawrence from Yale by offering him tenure, graduate students, and opportunity for rapid advancement—uncommon perquisites for a fresh-faced academic at an Ivy League university. Lawrence moved to Berkeley in 1928, settling into an office on the second floor of LeConte Hall, the physics building. He set up shop in an old wooden building next to LeConte Hall that he saved from demolition, renamed the Radiation Laboratory, and made his personal fiefdom.
The instruments in the “Rad Lab” were first-class, but almost nothing else was. The centerpiece was a twenty-seven-inch cyclotron—twenty-seven inches for the size of the poles of its eighty-ton electromagnet. The electromagnet was massive, twelve feet high and twelve feet long in its semicircular arch. Inside the arch, set on its side, was a metal spool shaped like an enormous barbell. From the narrow neck of the spool spread out a web of wires and cables. Here the particles were accelerated and the targets set. The building was so full of static electricity that one could light up an electric bulb by touching it to any metal surface. 9
Before Lawrence, there had been a proud tradition that a physicist conducted research only with personal tools. The cyclotron required a big team. This was all part of Lawrence’s plan. His approach was to assemble teams devoted not only to solving specific problems but to applying discoveries across disciplines. By teaming up physicists, chemists, biologists, physicians, and engineers, he increased his odds of producing the practical applications that would bring him the fame and funding he wanted. 10
The Rad Lab was an exciting place for an experimental physicist. Lawrence had a tremendous enthusiasm for the work, an enthusiasm that was very infectious. Everyone wore a wraparound apron with a sash tied in front—it was a kind of badge that showed you were “in.” Everyone knew it was one of the most outstanding physics laboratories in the world. They felt a sense of adventure and participation in an important activity with important people—especially Ernest Lawrence, whom they affectionately called “the Maestro.” Occasionally Lawrence would don an apron himself and work alongside everyone else. When he did, things went a little faster, his focus on the acquisition of physical data, not on what the data meant.
Operating independently of the physics department, Lawrence was a scientific entrepreneur who had shrewd business sense and was skilled at raising money for his laboratory. Measured against the standards of later years, the money he raised was small, but it was an astronomical sum for science during the Depression, especially for what was then considered an esoteric field. Introducing the big-machine approach to science, he became a sovereign in his own realm.
He also put Berkeley on the map. Lawrence knew he had arrived when he was invited to the prestigious Solvay Conference on Physics, held in Brussels in October 1933, the only American so honored. Other invitees included such giants of physics as Einstein, Bohr, and Fermi. By the mid-1930s Lawrence was the youngest full professor at Berkeley, with an army of graduate students. Berkeley’s chancellor, Robert Sproul, exaggerated only a little when he quipped, “I don’t know whether I’m running a university with a cyclotron attached to it or a cyclotron with a university attached to it.”
The boyish, clean-cut Lawrence was an exceptional salesman and handler of people. He instinctively knew how to make a good impression—particularly on those he sought to flatter—and was scrupulously polite, even to those he did not particularly like. As he worked a room like a master politician, foundation officers and industrialists found him hard to resist. His presence and salesmanship grew out of an inexhaustible energy and optimism that impressed everyone who met him.
Underneath the charming smiles and friendly backslaps, however, lurked an intense, driven man who clenched his jaw and had little time for “nonsense.” When he lost his cool, a vein in his left temple bulged out—it became a warning sign to everyone. 11 Assertive and at times overbearing, he identified personally and passionately with the Rad Lab. It was his laboratory—he had created it from scratch—and he ran it with an iron fist. “This was Lawrence’s domain,” said Philip Abelson, one of his graduate students. “He was number one. He was running the show.” 12 Lawrence was omnipresent, demanding, and dominating. He hung a huge microphone from the lab’s ceiling so that he could talk to the staff from his office—and listen to them. Some staffers found him overbearing and pompous—“a man with an inflated ego.” 13 During midmorning coffee breaks, Lawrence used a fine china cup and silver spoon, while everyone else made do with thick porcelain mugs. At the end of the break, the cup and spoon went into a locked drawer conspicuously marked RESERVED FOR THE DIRECTOR. 14 His cyclotrons cost loads of money to construct and operate, yet the staff who ran them had to make do with small salaries and no benefits such as medical insurance.
Lawrence was quintessentially American—he believed anyone could do anything if he just put his mind to it. “Keep your nose to the grindstone, there’s nothing more interesting than physics,” he often said. 15 He chose his staff carefully, preferring uncomplicated people willing to work long hours. Laziness was not tolerated. “He wouldn’t hesitate to bawl you out or tell you [that you] were doing things wrong,” recalled Edwin McMillan, whose years in the Rad Lab eventually won him a Nobel Prize. “The greatest sin was not working hard enough. That was a worse sin than doing something badly.” 16 He dropped in to the Rad Lab at odd hours of the night—often dressed in black tie after a dinner party at Sproul’s house—just to see how things were going. He also kept a radio by his bedside at home tuned to the cyclotron frequency to know that it was running. If it was not, he would get on the phone and bark, “What the hell’s the matter? Having coffee, or were you out for a beer?” 17
As the administrative and fund-raising burden increased, Lawrence grew distant from the day-to-day work of the Rad Lab. He was often away in New York, where his main financial supporters were located. These trips occupied more time than necessary, since he insisted on going by train—he would have nothing to do with airplanes. In spare moments he hosted friends at favorite restaurants like DiBiasi’s in Albany and played tennis to win. His family and friends worried that he wouldn’t be able to keep up the frenzied pace and that one day his health would suffer. But Lawrence was not the worrying type.
By the late 1930s Lawrence had made himself and his Rad Lab world-famous. MIT’s president wrote him: “I believe [the Rad Lab] to be the most interesting and important scientific work now going on anywhere in the world.” 18 In Russia, cyclotrons were called “Lawrences.” When a model cyclotron was set up at the Golden Gate International Exposition on Treasure Island in San Francisco Bay in 1939, Lawrence spoke about it on a national radio hookup with a showmanship worthy of P. T. Barnum. That same year he won the coveted Nobel Prize in physics.
Lawrence was sarcastic and impatient with Berkeley colleagues who explored schemes for alleviating the lot of humanity. Political issues did not excite or engage him. His view of international affairs was even more naive and simplistic. Like the vast majority of Americans during the isolationist 1930s, he thought Europe’s “shenanigans” should be ignored because they were not America’s business. In October 1938 he wrote to Wilfred Mann, a British physicist who had done research at the Rad Lab, commenting on—among other things—the recent Munich Conference, where Britain and France had sacrificed Czechoslovakia to Nazi Germany on the altar of appeasement:
Dear Wilfred:
You have been having a very anxious time recently, but let us hope the war clouds have passed and that we have ahead of us at least a decade of peace. I don’t think it absurd to believe it is possible that we have seen a turning point in history, that henceforth international disputes of great powers will be settled by peaceful negotiations and not by war.
Cordially,
Ernest
19
“I still think war is going to be avoided,” he wrote his parents on August 29, 1939, adding confidently: “All this discussion certainly must mean that Hitler is backing down.” 20 Three days later Nazi Germany invaded Poland and started World War II.
Oliphant and his British sponsors knew that if they could convince Lawrence of the feasibility of a bomb, Lawrence would grab hold of the idea and push it relentlessly in American scientific circles, while leaving the political ramifications to others. They thought Lawrence would get it done without asking too many questions. And although Lawrence was quite clearly a political naïf, they had chosen just the right man.
The relationship between Britain and America was growing closer when Oliphant traveled to Berkeley in late September 1941. Though still a nonbelligerent, the United States was far from neutral. Its sympathies lay with the hard-pressed British, who had survived a Nazi aerial blitz the previous summer. In the fall of 1940 the Roosevelt administration had transferred fifty destroyers to Britain in return for U.S. rights to build bases in British possessions in the Caribbean and the western Atlantic, and Congress had passed the first peacetime military draft in American history. In the spring of 1941 direct Lend-Lease aid to Britain began. The United States was edging toward war on the side of Britain.
On Sunday, September 21, 1941, Lawrence picked up Oliphant at the San Francisco train station in his car and drove up into the green hills above the Berkeley campus, where the magnet for his giant new 184-inch cyclotron was being erected on the summit of Charter Hill. It was a beautiful autumn day and far below, beyond the gardens and lawns of Berkeley, the bridges of San Francisco Bay shone in the sun. Lawrence’s driving petrified Oliphant. Pressing the accelerator to the floor and keeping his face turned toward his passenger, Lawrence threw the car forward in jerks and spasms, swaying from one side of the twisting dirt road to the other, cutting corners at full speed, paying no heed to other cars as they passed.
Nervously gripping the door handle, Oliphant told Lawrence about Frisch and Peierls’s calculation that a bomb could be made with just a few kilograms of U-235, and about the methods under study in Britain for separating the isotope from natural uranium. Lawrence was deeply impressed by the serious view of British scientists not only that atomic bombs were quite possible but that Nazi Germany might be working on the problem. He suggested the possibility of extracting U-235 through electromagnetic separation using his new 184-inch cyclotron. He began to describe to Oliphant a fantastic vision of gigantic laboratories and industrial complexes, armies of specially trained scientists and arsenals of newly invented tools and instruments, his voice rising with excitement. It was a contagious exuberance that overwhelmed doubt and drowned all sense of reality in a flood of buoyant optimism. When Lawrence was talking, it was impossible not to fall under the almost hypnotic spell of his enthusiasm—he even convinced himself. Here was something big enough, Oliphant thought, for Lawrence’s talents and ambition. That other physicists might find such a vision fantastic would only spur him to prove them wrong.
Lawrence immediately put his Rad Lab staff to work. A chemist at the Rad Lab, Glenn Seaborg, had recently hit upon the discovery that neutrons absorbed by U-238 transformed uranium into a heavier element—plutonium—that also was fissionable by slow neutrons. This was an accidental but important discovery, just like fission had been. Not only could plutonium be made in a chain-reacting pile, but it was a different chemical element, not just another isotope of uranium, and could therefore be separated from U-238 through a comparatively easier and less expensive process than U-235. Lawrence reasoned that plutonium might supplement U-235 as a source for atomic bombs.
In the fall of 1941—a time when the war was going very badly for Hitler’s enemies—Lawrence instructed Rad Lab scientists to convert the cyclotrons for use in the electromagnetic separation of U-235. It was an extremely slow, complicated, and expensive way to produce fissionable material for a bomb. By February 1942 the Rad Lab had produced three samples of U-235 weighing all of seventy-five micro-grams each. A microgram was a speck barely big enough for the eye to see, and each sample contained only 30 percent “enriched” U-235. Lawrence had a long way to go—how was he going to separate kilograms of pure fissionable U-235? Lawrence had committed himself to the goal, however, and was absolutely determined to see it through. “That was just the beginning,” he said with great assurance. 21 He told his contacts in Washington that the project should be expanded to bring in more scientists and to build the infrastructure necessary to accomplish the task.
Driven by a determination that Hitler not get the bomb first, Lawrence drove himself and his staff relentlessly. He demanded complete dedication to the task at hand. He worked long hours and expected others to do the same. When delays occurred or things went wrong, he bawled people out unmercifully, though he never asked others to do anything he would not do himself and he showed appreciation for results. He led by example and maintained his leadership through the intensity with which he followed the isotope-separation work. He believed that if you wanted something to come true, you made it come true by pushing like hell. Somehow a way could be found, and he had faith that he would get there. With such effort, he thought, nothing was impossible.
Lawrence met the Rad Lab staff every morning at eight. People took pains to be already in their seats. The Maestro made a grand and lordly appearance, stomping in, slowly striding the length of the room, pounding the floor with his feet. Beaming at the assembled staff, he took his seat in a big red leather armchair facing sideways between a blackboard and the audience. The thing to do, he would then announce, was to get the job done—he expected everyone to share his sense of urgency. Later in the day he would walk unannounced through the lab and query people about their work. He did not say much. Often it was simply, “What are you doing? Why are you doing that?” If they answered hesitantly or pessimistically, Lawrence frowned. If they went into detail, he looked impatient. Above all, he hated idleness; there was an important job to be done and no time to waste in doing it. “The esprit has perked up considerably with everybody conscious of the necessity to work like the devil,” wrote one Rad Lab staffer after a surprise visit by the director. 22
The fast pace, constant work, and self-imposed stress took its toll on Lawrence. His full head of blond hair began to recede. His thin, muscular face grew puffier and pastier. Once remarkably energetic, he now was slowed by frequent and severe colds and a chronic backache. On those rare occasions when he went home early for an evening with his family, he usually tired after a few minutes of hugging and tossing around his children. Neighborhood kids, used to congregating noisily at the sprawling Lawrence home in the afternoon, frayed his taut nerves and were abruptly ordered out. He found it much more difficult to relax than to wrestle with the atomic project.
Lawrence felt in his bones that an atomic bomb could be made. He was confident that America possessed the ability and resources to do it. He insisted that prudence required stepping up research, if only because of what the Nazis might be doing. Szilard and Teller had said much the same before, but as refugees they were not trusted by close-minded government bureaucrats. They also lacked Lawrence’s dogged optimism.
But although Lawrence’s hard sell worked with many people, it did not with Vannevar Bush. A fit man of fifty-two, Bush was a shrewd Yankee who was also an astute administrator with distinguished accomplishments: endless engineering patents, the vice presidency of MIT until 1938, then direction of the Carnegie Institution of Washington, a premier research organization. Now he was the scientific adviser to President Roosevelt, and in that capacity, head of the Office of Scientific Research and Development (OSRD), which had been established by executive order (under the name National Defense Research Committee) * on June 27, 1940, the day after the Nazis occupied Paris.
The mission of the OSRD, which had absorbed the Uranium Committee, was to mobilize the nation’s scientific resources and apply them to national defense. This included support of research that would result in weapons applicable to the present war. To Bush, the defense of the free world in the fall of 1941 was in such a perilous state that only research efforts likely to yield quick results were worthy of serious consideration. He therefore thought physicists such as Lawrence should concentrate their efforts on projects that promised results within a matter of months, or at most a year or two—like radar and sonar. In Bush’s opinion, America could not afford to devote its limited scientific resources to an extravagant program of uncertain success.
More significant than Lawrence’s prodding was the MAUD Committee Report, which a British scientific liaison officer passed along to Bush on a visit to Washington in early October 1941. The report’s optimism about techniques for isotope separation and the prospects for development of an atomic bomb diminished his skepticism at the same time that it increased his fear of Germany’s success in exploiting fission. Bush took the MAUD Report to the White House on October ninth. He summarized its conclusions for the president: that the explosive core of a fission bomb might weigh twenty-five pounds; that it might explode with a force equivalent to nearly two thousand tons of TNT; that a vast industrial plant would be necessary to separate the fissionable U-235; and that British scientists estimated the first bombs might be ready in two years. He emphasized that he based his statements “primarily on calculation with some laboratory investigation, but not on a proved case,” and therefore could not guarantee success. 23
Roosevelt’s mood had changed considerably since Einstein’s letter two years earlier. The war felt much nearer and more nearly inevitable for the United States in 1941 than it had in 1939. If the British were pursuing such a promising line of research, it seemed quite possible that the Germans were, too. No president could assume anything less. Thus, FDR endorsed an American atomic project and directed that consideration of policy—what might be done with a bomb, if it was made—be restricted to a Top Policy Group consisting of Vice President Henry Wallace, Secretary of War Henry Stimson, Army Chief of Staff George Marshall, Bush, and Bush’s OSRD deputy, James Conant, a noted chemist and president of Harvard University. Roosevelt emphasized the importance of keeping knowledge of the project within the smallest possible circle, a theme he would stress again and again throughout the war. Within the next few months the organization, the tempo, and the attitude of the American government toward research on an atomic bomb would alter dramatically.
The United States was not yet committed to building an atomic bomb, but it was now committed to exploring whether one could be built. With Roosevelt’s permission, Bush ordered a feasibility study and a timetable. What were the prospects of making an atomic bomb? Could it be finished in time to help win the war? Should Washington fund an all-out effort when research funds were limited and other projects of more immediate promise and effectiveness—such as radar and the proximity fuse—existed? To answer these questions, Bush chose a senior American physicist with a Nobel Prize, excellent contacts, and long experience on the national scientific scene named Arthur Compton.
Broad-shouldered and athletic with a thick mustache, deep-set gray eyes, and a strong chin, Compton was a professor of physics at the University of Chicago. Principled and firm yet pragmatic, Compton fit neatly and easily into the project: he was popular in scientific circles, he had an agreeable disposition, and he had powerful connections. Scion of a famous American scientific family—his brother Karl was president of MIT—Compton was not policy-oriented like Bush but was trusted by high officials in Washington whose background and upbringing was similar to his own: a midwestern childhood in a mid-western family with midwestern Protestant beliefs. Compton moved easily in the world of the American Establishment.
As a boy, Compton had listened spellbound as his father described the discovery of a new chemical element that glowed with brilliant luminosity: radium. What especially intrigued him was that radium was warm to the touch. Where did such heat—radioactivity—come from? Could this heat be exploited for energy? Such questions stirred his imagination. When Compton was twelve, he sat on the front porch one night. The winter air was crisp and clear as he watched pinpricks of starlight. He felt a sense of wonder and sat up “all night, astonished, among the stars.” 24 Soon he was spending every night in the backyard, searching the face of the moon with binoculars until he memorized its cratered features. He bought a telescope with his savings and used it to view the moons of Jupiter. By putting a piece of welder’s glass in front of the telescope, he even watched the sun. He began to feel a “strong emotional stirring,” as he later put it, about science. 25
Compton became a physicist and demonstrated his brilliance early in his career when he won a Nobel Prize in 1927 for his study of X rays, following that up with pioneering work on cosmic rays in the 1930s. Compton’s bold experiments in the new field of cosmic rays were carried out at high altitudes in the Himalaya, the Andes, and the Artic, and at the Equator. Travel to far-flung corners of the globe taught the midwesterner that other people of other cultures and colors were just as human as he. And it introduced him to such European physicists as Szilard, Fermi, and Bohr, whom he came to know well.
Compton visited Fermi at Columbia in October 1941 to gather firsthand information on neutron fission. He also heard from Lawrence, who warned him that an atomic bomb “might well determine the outcome of the war.” 26 Compton told Lawrence to make his case directly to Conant: the Harvard president and Lawrence both planned to be in Chicago soon to attend celebrations honoring the fiftieth anniversary of the founding of the University of Chicago. The following week the three met at Compton’s rambling home on Woodlawn Avenue a few blocks north of the campus. It was a crisp autumn evening. With steaming cups of coffee, the three scientists gathered around the fireplace in the wood-paneled study. Lawrence reviewed British calculations that a bomb could be made with just a few kilograms of fissionable material. He also mentioned his lab’s discovery of plutonium, emphasizing that it fissioned like U-235 but could be chemically separated from U-238 much more easily. He insisted that an atomic bomb could be made. No other physicist would stake his reputation on such an unproved assumption. But Lawrence’s confidence was supreme; his enthusiasm swept away whatever doubts lingered—in Compton’s mind, at least.
Conant was still reluctant. A seasoned administrator and savvy player well schooled in the cautious bureaucratic ways of Washington, Conant believed physicists should work on problems certain to be helpful because the country could not afford to waste limited resources on projects of questionable military value. Looking at Lawrence, he said, “Ernest, you say you are convinced of the importance of these fission bombs. Are you ready to devote the next several years of your life to getting them made?” “If you tell me this is my job,” Lawrence said without missing a beat, “I’ll do it.” Conant asked Compton to examine the evidence and get a report to Bush as soon as possible. “If this matter is as critically important as you men indicate,” Conant said, “we mustn’t lose a day.” 27
Compton presented his report to Bush on November sixth. It was brief and to the point. He took the problem apart, examined it thoroughly, and reached firm conclusions on all the subjects within his scientific competence. He endorsed the brilliant insight of the Frisch-Peierls paper with the authority and depth of an American Nobel Prize winner—credentials that were indispensable to the task of persuading official Washington. He reported that “a fission bomb of superlatively destructive power will result from bringing quickly together a sufficient mass of element U-235” and that “the separation of the isotopes of uranium can be done in the necessary amount.” Compton also addressed the crucial issues of time and cost. Three to five years would be needed, he estimated, and several hundred million dollars. His bottom line was this: atomic bombs could be made. 28
Bush was impressed. He concluded that the possibility of a wartime bomb was strong enough that every effort must be made to find out if it could be built. Bush knew how to get this done. He kept his memoranda short and cogent. He took no public credit for getting things accomplished. He understood the bureaucracy and the military. And he knew how to persuade President Roosevelt.
Compton was not above some personal lobbying of his own. After submitting the report to Bush, he arranged a game of tennis with his personal friend, Vice President Wallace. As they chatted on the court, Compton told Wallace that Bush would soon be showing the president a report. “Please give it your most careful attention,” he said. “It is possible that how we act on this matter may make all the difference between winning and losing the war.” 29
Bush carried Compton’s report to the White House on November twenty-seventh. The weather that day was cold and the news was bleak. Hitler’s armies, which had invaded Russia in June, had reached the outskirts of Moscow and a crisis was brewing between America and Japan in the Far East. Bush proposed to Roosevelt an all-out effort to build a bomb. He told FDR that although Britain was ahead of the United States in bomb research, it lacked the resources to build one and looked to America to do so, if it was possible. The United States was the only country with uncommitted and protected resources sufficient to make an atomic bomb during the war.
Roosevelt followed intently. He had listened to Sachs and his account of the refugee physicists’ fears, and had politely thanked Einstein. But what he had now was not a vague idea but a clear proposal for action that came with the combined authority of British science and an American scientist whom he trusted. This combination had the commanding prestige that was necessary to give credibility to something as implausible as a one-kilogram device with an explosive force of some two thousand tons. And so, on December 6, 1941—just one day before Japan attacked Pearl Harbor and plunged the United States into the war—FDR put the vast resources of the government behind an all-out effort to build an atomic bomb. 30 The authority for deciding how the bomb would be used went to the Top Policy Group he had named earlier. The assumption that the bomb would be built quickly for use during the war was implicit in the decision to develop it.
Now the entire governmental machine began to get to work on the effort, code-named the Manhattan Project, after the headquarters of the Army Corps of Engineers’ district tasked to manage it. Bush appointed Conant to oversee the scientific project from Washington and gave Compton responsibility for academic research throughout the country. Bush also made clear the government’s intent to maintain authority over the project and to transfer it to the army’s control when large-scale production of fissionable materials became necessary. His reasons were simple: Bush knew the money was running out from sources at his disposal and much more was going to be needed. By bringing in the military, he could conceal the project’s costs within the Army Corps of Engineers’ enormous appropriation under line items dubbed “Procurement of New Materials” and “Expediting Production.” Roosevelt did not want to have to justify the Manhattan Project on the Hill. This might slow down the project and jeopardize its secrecy. 31
Many of the physicists who would soon be brought into the Manhattan Project were refugees, recent immigrants to the United States. This was partly because they included some of the world’s best physicists, but there was another reason as well: many native-born American physicists had been swept up earlier in military research on radar and the proximity fuse, which appeared to have a more immediate military application to Allied success in the war. As a result, refugees were the main remaining source of available scientific brainpower to work on the project. The very restrictions and limitations imposed upon refugee scientists—which had delayed the government’s embrace of the project—facilitated their leading roles in the bomb’s development once the government decided to support it. 32 This irony would have a significant, if unstated, impact down the road, when disputes arose about the long-term political consequences of what the scientists and the government were doing.
In the end, the refugee physicists and their native-born colleagues did not protest their loss of control over the project in December 1941. Most of them, in fact, welcomed it because they thought it would insulate them from political pressure and criticism. Their acceptance of this condition was the tacit price of their admission into the project. It was also a measure of their loyalty by those at the top. “I think [Ernest Lawrence] now understands this,” Bush said, “and I am sure Arthur Compton does, and I think our difficulties in this regard are over.” 33 The government was giving physicists, whom Bush and others in top councils considered “somewhat naive and lacking in discretion,” 34 the responsibility for making an atomic bomb, not for helping to decide how it would be used.
Oak Ridge was a remote rural area surrounding the Clinch River eighteen miles from Knoxville, Tennessee. It was beautiful country, rolling hills dotted with dogwood, oak, and pine trees, and situated between the Great Smoky Mountains to the east and the Cumberland Mountains to the west. It answered all the requirements for a sprawling plant to separate U-235 isotopes: an isolated area in the midst of the vast power grid of the Tennessee Valley Authority, an abundant water supply, relatively few people to relocate, good access by road and train, and a mild climate that permitted outdoor work the year round. Here on a 59,000-acre site, 32,000 construction workers built and 47,000 operating personnel maintained a gigantic forty-two-acre separation plant flanked by facilities covering some fifty additional acres and containing more than six thousand miles of pipe that was the largest factory complex on earth when it was finished.
U-235 was separated at Oak Ridge by three different methods—no one knew which would prove most effective. The first method was electromagnetic separation, using giant cyclotrons designed by Ernest Lawrence. Uranium atoms were stripped of electrons in a vacuum. Then they were electrically charged and thus made more susceptible to outside magnetism. The heavier U-238 was more sluggish, so the lighter U-235 could gradually and painstakingly be separated out. The enormous separation chambers contained vacuum pumps, more powerful than any ever built, that pushed through millions of gallons of oil a day; the magnet coil windings required 27,750,000 pounds of silver (the metal, worth $400 million at 1940s prices, was borrowed from the Treasury Department).
The second method was gaseous diffusion, developed by Columbia University physicists Harold Urey and John Dunning. When ordinary uranium was mixed with fluorine, the resulting compound—uranium hexafluoride—was a gas. When the uranium hexafluoride gas was forced through the microscopic membrane holes of a filter (or “barrier,” as it was also called), the lighter U-235 passed through faster and the gas on the far side was marginally enriched with the desired isotope. When the process was repeated, the proportion of U-235 increased a little more. Bomb-grade uranium—containing 90 percent U-235—required thousands of passes through the filters.
The third method of U-235 separation was thermal diffusion, pioneered by a former student of Lawrence’s working at the Naval Research Laboratory named Philip Abelson. The apparatus was simple. Long, vertical, concentric pipes were enclosed in cylinders that resembled a gigantic church organ. Each cylinder was composed of a thin nickel pipe within a copper pipe. These two pipes, in turn, were encased in a third one made of galvanized iron. When uranium hexafluoride gas was passed between the hot nickel pipe and the cool copper pipe, the lighter U-235 concentrated near the hot nickel wall and moved upward, while the heavier U-238 moved downward along the cool copper wall. The enriched uranium was then skimmed off at the top. Thermal diffusion could increase the percentage of U-235 in natural uranium by only a small amount, but the enrichment was sufficient to supplement the gaseous diffusion method as another source of material for the electromagnetic racetracks, whose efficiency soared tremendously when fed with even slightly enriched uranium.
The names of the processing plants at Oak Ridge sounded like the combination to a safe: X-10, Y-12, S-50, K-25. All plants except X-10, a plutonium research lab, performed the same function: extracting precious U-235 from U-238. At S-50, thermal diffusion was employed; at Y-12, electromagnetic separation was applied; at K-25, the process was gaseous diffusion. K-25 was the largest building ever constructed up to that time. It was a sight to behold. Spread over 2 million square feet, the U-shaped structure was half a mile long and four hundred feet wide on each side. It was so vast that foremen rode bikes from one part of the building to another. Twelve thousand people, working in three shifts, kept K-25 running day and night, seven days a week. When it was operating, a continuous hum—a high-pitched sound resembling the buzzing of a bee swarm—came from the plant, mixing weirdly with the noises from the nearby woods. The electricity for these mammoth facilities came from the nearby TVA and an on-site powerhouse that was the largest power installation ever built. By war’s end, Oak Ridge would be consuming the equivalent of the total power output on the American side of Niagara Falls—or one-seventh of all electricity generated in the United States.
Lawrence toured the sprawling complex as it was being built, and thrilled at the spectacle. “What you’re doing here is very important,” he told construction workers assembled to hear him give a pep talk. Oak Ridge was a realization of his vision of big physics, and it made him feel proud—like King Henry V addressing his troops before the Battle of Agincourt. “A hundred years from now, people may not remember that there was a war on now,” he told them, emotion rising in his voice, “but they will remember what you were doing.” 35 Privately, Lawrence was awed by what lay ahead. “When you see the magnitude of that operation there,” he wrote after returning to Berkeley, “it sobers you up and makes you realize that whether we want to or not, we’ve got to make things go. We must do it!” 36
The magnets of the cyclotrons that Lawrence had built at Oak Ridge were 250 feet long, and each contained thousands of tons of steel. They were a hundred times larger than the magnet of the 184-inch Berkeley cyclotron—previously the largest in the world. Their magnetic field was so strong that a wrench would be wrested from a workman’s hand, or if he held onto it, he would be pulled against the magnet. But the U-235 separated by these giant cyclotrons offered itself up in only minuscule quantities. Yields were so low from the tons of uranium ore being processed that workers carefully plucked mere specks from their white overalls with tweezers. There were times when they got down on their hands and knees to look for tiny bits of the precious fissionable material.
In south-central Washington State, the small town of Hanford sat in the midst of a vast area of sagebrush and sand, twenty miles north of Richland, bounded on three sides by a huge bend in the Columbia River. This unusual combination—large amounts of water flowing through sparsely peopled desert—made the site suitable for another prong of the Manhattan Project. The Columbia River would provide the enormous amount of water necessary to cool three gigantic piles to be built there for the production of plutonium, an alternative (and more easily obtained) source of fissionable material for the bomb. The isolated location—the population density was just 2.2 persons per square mile—would mitigate the effects of any accidental radioactive release and be easy to guard. In time, the Hanford facility would grow to more than 428,000 acres—500 square miles. 37
To recruit a massive labor force of construction workers for the Hanford site at a time when every war industry in America was begging for manpower was an extraordinary task. The White House cabled regional employment offices, giving preference by direction of the president himself to the Hanford Engineering Works, as it was called, and authorizing them, if necessary, to draft workers from the aircraft industry. In some towns of the Northwest, clergymen were asked to promote Hanford from the pulpit. Veterans of many big public works projects—men who had helped construct huge dams and power plants—had never seen so many people working in the same place at the same time. Living in barracks and trailer camps, they created a massive, sprawling physical plant. The statistics were stunning: 540 structures, more than 600 miles of blacktop, 158 miles of track. Eventually, 132,000 workers (working 126 million man-hours) signed on—nearly as many as had labored to build the Panama Canal. Hanford soon became the fourth-largest city in the state of Washington. The ultimate price of Hanford would reach $358 million, or nearly $5 billion in 2004 dollars. 38
Hanford’s three all-important piles—each one processed two hundred tons of uranium for two hundred days—produced the plutonium, but equally important were the chemical-separation plants that treated the uranium slugs irradiated in the piles. These slugs were so radioactive when they came out that they glowed. 39 Three chemical-separation plants were built in isolated and heavily guarded desert areas south of nearby Gable Mountain. For safety reasons—the plutonium in the irradiated slugs was also highly radioactive—the plants were placed ten miles from the nearest pile and well apart from one another. No one wanted to discover an atomic blast by accident.
The separation plants were sinister-looking, windowless structures with walls eight feet thick—in effect, huge concrete coffins eight hundred feet long and eighty feet wide. Each contained an underground row of forty cells where the irradiated slugs were processed. The operating gallery that ran above the cell rows was a silent, deadly radioactive tunnel with glaring electric lamps, where no human being could survive. Because of plutonium’s deadly toxicity, metallurgists had to be specially trained to handle it. They wore rubber gloves, worked behind protective shielding, and manipulated the plutonium with long tongs. Not only was the air filtered and ventilated, but a microscopist was hired to analyze its dust. In these gargantuan coffin- like structures, workers operating remote-control machinery around the clock tortuously squeezed out plutonium in a concentration of about 250 parts per million, a half-pound radioactive pellet from every ton of irradiated uranium.
To build a bomb from materials that didn’t yet exist in measurable quantities, involving the commitment of an extraordinary range of human and material resources, in the midst of a global war—it was an improbable undertaking. Yet out of nothing would be created a vast industrial enterprise. Bohr’s prediction had not been far off the mark: before the war was over, the Manhattan Project would consume more than $2 billion, employ 500,000 people directly and indirectly, and mobilize vast material resources. The project exemplified human ingenuity and determination, an immense undertaking into which industrial power was harnessed at vast cost and extraordinary effort. There was something vitally American about the Manhattan Project: no other nation in a world at war had the time and money to attempt such a thing.
An all-out race to build an atomic bomb was now under way after a delay of more than two years. Scientists entered the race—against German scientists believed to have a two-year head start—convinced that the outcome of the war depended on their ability to recover lost time. For them, the bomb’s rapid development was the single most important necessity of the war. It was a matter of survival.