by Steve Olson
The physics department at Berkeley was even stronger. On the experimental side, it centered on Ernest Lawrence, the inventor of a device called a cyclotron. Though Lawrence was 11 years older than Seaborg, the two men had many things in common. Lawrence was born and raised in a small town in South Dakota and attended the University of South Dakota, where a charismatic teacher steered him away from premedical studies to physics. After receiving a PhD at Yale in 1925, he was lured to Berkeley by a generous salary and a promise of plenty of time for research. He conceived of the cyclotron one evening in 1929 while leafing through an obscure journal in the Berkeley library. Gazing at a half-understood drawing, he suddenly thought how he could use circular magnets and a rapidly fluctuating electrical field to accelerate charged particles to speeds never achieved before. He immediately knew the significance of what he’d found (he received the Nobel Prize for the discovery 10 years later). The morning after his evening in the library, encountering the wife of another faculty member on a campus walkway, he told her, “I’m going to be famous.”
On the theoretical side, the Berkeley physics department revolved around a radically different man. J. Robert Oppenheimer was the son of wealthy, nonobservant Jewish parents who lived on the Upper West Side of Manhattan. A polymath in the elite private school he attended, he read the classics in Greek and Latin, studied French poetry, and was tutored by the curator of the American Museum of Natural History—all in high school. He studied chemistry, physics, philosophy, and mathematics at Harvard and then physics in Europe, receiving his PhD after an oral examination administered by the German physicist James Franck. As Franck said afterwards, “I got out of there just in time. He was beginning to ask me questions.” During high school and afterwards, Oppenheimer had spent several summers on a ranch in New Mexico, and his love for the West was a factor in his arranging for joint positions at the California Institute of Technology and at Berkeley, starting in 1929, when he was just 25 years old. In both institutions, he was surrounded by a contingent of graduate students who tended to mimic his mannerisms, including the strange humming he made between paragraphs of impeccably crafted prose. They were sometimes called the “nim nim boys.”
Ernest Lawrence, Glenn Seaborg, and Robert Oppenheimer at the controls of Lawrence’s University of California, Berkeley, cyclotron. The men were at the center of America’s effort to build atomic bombs. Courtesy of the US Department of Energy.
In the midst of all this scientific talent, Seaborg was at times overwhelmed. “I couldn’t get over the feeling that I’d been plucked from the minor leagues and put on a major league all-star team. The world is filled with talented prospects who can’t hit the curveball—would I turn out to be one of them?” He solved the problem with midwestern good sense: he resolved to work as hard as he possibly could. “That has proved to be the secret of whatever success I’ve had, if you call such a pedestrian notion as hard work a secret. Looking back, I can say that my whole life I’ve been surrounded by people who are brighter than I am, and I’ve done my best to take advantage of having them to work with.”
Seaborg threw himself into graduate school life. He took courses, attended seminars led by Lewis, Lawrence, and Oppenheimer, taught an introductory chemistry lab to make money, and sought out an advisor whom he thought would give him lots of freedom to pursue his own path. His education at UCLA had given him a solid grounding in both chemistry and physics, and the intersection of physics and chemistry is where the excitement was at Berkeley in the 1930s. He got to know the physicists in the building at Berkeley that housed the cyclotrons—known as the Radiation Laboratory or Rad Lab. It was so full of radio waves, Seaborg recalled, you could light an electric bulb by touching it to any metal surface. He was an energetic and enthusiastic young graduate student eager to make his mark on the world.
IN 1934, THE SAME YEAR that Seaborg started at Berkeley, more remarkable scientific news emerged from Europe. Since the end of the 19th century, scientists had known that the heaviest elements found in nature, like radium and uranium, are unstable. Their nuclei emit subatomic particles like electrons and alpha particles (consisting of two protons and two neutrons) along with high-energy packets of light known as gamma rays, which scientists had collectively termed radiation. In the process, heavy elements gradually change from one element to another until they find a stable configuration of protons and neutrons.
This, too, makes sense. The more protons an atom has, the more fiercely they repel each other. The heaviest elements have lots of neutrons to hold their protons together—the most common isotope of uranium has 146 neutrons compared with 92 protons. But even a superabundance of neutrons is not enough to render heavy elements completely stable, and eventually they decay to lighter elements.
In January 1934 the husband and wife team of Irène and Frédéric Joliot-Curie (they hyphenated their last names when they were married) made an astonishing discovery. All elements, it turns out, have isotopes that are radioactively unstable. Bombarding any element with subatomic particles can create nuclei with unstable combinations of neutrons and protons that do not exist in nature. Physicists had assumed that such combinations would immediately fall apart. Instead, these oddball collections of protons and neutrons stick together, but just for a while. Over time, just like heavy elements, these unstable isotopes of light elements decay to new combinations of protons and neutrons until they find a stable configuration.
The discovery of what the Joliot-Curies termed artificial radioactivity was just as momentous as the discovery of the neutron. Suddenly, the universe consisted of much more than stable light elements and radioactive heavy elements. By bombarding stable elements with subatomic particles, physicists could create radioactive isotopes, or radioisotopes, with new, unusual, and highly useful properties. It was as if the surface of reality had gone transparent and revealed a shadow world beneath.
THE DISCOVERY OF ARTIFICIAL RADIOACTIVITY made Lawrence’s cyclotron at Berkeley into a scientific goldmine. By bombarding different elements with fast-moving particles accelerated by the cyclotron, the Berkeley physicists could produce a virtually unlimited number of new and previously unknown radioisotopes.
With his background in both chemistry and physics, Seaborg was perfectly positioned to join the radioisotope hunters at Berkeley. Still, as a wet-behind-the-ears graduate student, he needed a break to get into the field. One day in April 1936, he was walking between the physics and chemistry buildings when a physicist named John Livingood stopped him. Livingood had been bombarding a target of tin in the cyclotron, seeking to create radioactive elements slightly heavier and slightly lighter than tin. Would Seaborg be interested in chemically separating the newly created elements from the irradiated target?
This was just what Seaborg needed. It would put him in direct contact with the work going on in the Rad Lab, an opportunity usually denied young graduate students. And once he started working on one project, he knew he would be caught up in others. He quickly set up a small lab in the physics building and bootlegged the chemicals and equipment he would need from the chemistry department. When Livingood brought him the irradiated tin, he dissolved the target in acid and added chemicals that combined first with the tin and then with indium (the element just before tin) and antimony (the element just after). “Deuteron-Induced Radioactivity in Tin,” which was published a few months later in Physical Review, was Seaborg’s first published scientific paper.
Over the next few years, Seaborg, Livingood, and their colleagues at Berkeley discovered dozens of radioactive isotopes, including several of the most important radioisotopes used in medicine and industry today. Cobalt-60 is used to treat cancer and sterilize medical instruments. Technetium-99 is used to image the liver, lungs, brain, and other organs. Iodine-131 is used to diagnose and treat thyroid problems. Seaborg later claimed that this last isotope was the most significant of all the ones he helped discover. Twenty-five years after its discovery, iodine-131 prolonged his mother’s life by a decade when sh
e contracted hypothyroidism, a disease similar to the one that had killed her sister.
Seaborg earned his PhD in 1937 for a thesis on the interactions of neutrons with lead. He then went to work for Lewis as a research assistant while continuing his own research in the mornings, during lunch breaks, and in the late afternoons and evenings. Seaborg was becoming more and more interested in the odd behavior of uranium and other heavy elements when they were bombarded by subatomic particles. They were giving off strange signals that were hard to interpret. Something interesting was going on in their nuclei, but no one could figure out what. Seaborg began spending more time with the physicists in the Rad Lab.
It was a backbreaking schedule, but Seaborg also took time to have fun. One night he and fellow chemist Willard Libby, who would win a Nobel Prize in 1960 for his development of carbon dating, went out with two other Berkeley colleagues and a young chemist named Henry Taube to celebrate Taube’s new PhD. After going to Trader Vic’s on San Pablo Avenue, where they drank Zombies to celebrate Taube’s achievement, they went to a Chinese nightclub on Tenth Street in Oakland. When they entered the club, the new doctorate holder, who would eventually win a Nobel Prize for his work on how electrons behave in metals, pitched headlong onto the floor, “the result of too many Zombies,” Seaborg recalled. “I wonder if any of the people in that night club who witnessed our arrival would have believed that three of us were to win Nobel Prizes.”
Chapter 2
THE CHAIN REACTION
ON TUESDAY, JANUARY 31, 1939, LUIS ALVAREZ, A 27-YEAR-OLD physicist working at Berkeley’s Rad Lab, was reading the San Francisco Chronicle while getting his hair cut at the student union building. On the second page he came across the following article:
200 Million Volts of Energy
Created by Atom Explosions
WASHINGTON, Jan. 29 (AP)—American scientists heard today of a new phenomenon in physics—explosions of atoms with a discharge of 200,000,000 volts of energy.
The article, though somewhat confused on the details, explained that German chemists had been bombarding uranium atoms with neutrons and had discovered that the atoms were splitting roughly in half to form much smaller atoms, a process they later termed fission. When the atoms split, they gave off immense amounts of energy—far more than the energy released in chemical reactions. Scientists quoted in the article, including the famous Italian physicist Enrico Fermi, said that the finding was comparable in significance to the discovery of radioactivity.
Alvarez jumped from the barber chair, his hair half cut, and ran up the hill to the Rad Lab. There he encountered fellow Rad Lab physicist Philip Abelson, who also had been trying to understand the odd behavior of uranium when it was bombarded with neutrons in the cyclotron. “I have something terribly important to tell you,” Alvarez said. “I think you should lie down on the table.” Abelson lay down next to the cyclotron’s control panel. Alvarez told him the reason he and other scientists around the world had been getting such strange results from the bombardment of uranium: the uranium atoms were splitting into pieces.
“When Alvarez told me the news, I almost went numb,” Abelson recalled. Like everyone else, he had assumed that the signals he was measuring from the bombarded uranium were coming from elements slightly heavier or slightly lighter than uranium. But the signals had been coming from much smaller atoms all along. Abelson realized that he “had come close but had missed a great discovery.”
Seaborg heard the news that evening at the weekly meeting of young physicists and chemists to discuss recently published papers. Some of the attendees didn’t believe it. That’s not what they had learned about atoms. Bombarding elements in the cyclotron produced elements just before and just after that element on the periodic table—it didn’t split the atoms into much smaller atoms. As Seaborg later put it, “If you hit a car-size boulder with a pick, you may chip off a piece, but you won’t split the boulder into two halves.” But now the German chemists were saying that hitting uranium atoms with neutrons was doing just that. It was splitting the atoms into barium, with 56 protons, and krypton, with 36.
Despite the others’ skepticism, Seaborg knew immediately that the Germans were right. For years, physicists and chemists had been puzzled by the variety of signals they were getting from irradiated uranium. The splitting of uranium atoms into smaller atoms, each of which produced its own radioactive signals, explained the results perfectly.
After the journal club, Seaborg was distraught. “I walked the streets of Berkeley for hours with the news whirling around my head,” he later remembered. “My mood alternated between exhilaration at the exciting discovery and consternation that I’d been studying this field for years and had completely overlooked the possibility of this phenomenon—and missed a chance for an astounding discovery.”
Other scientists were equally dismayed. When the physicists at the Rad Lab had bombarded uranium in the cyclotron, they had noticed jolts of energy on their radiation detectors. But at the time they had decided that their detectors were malfunctioning and had turned them off rather than searching for the source of the signal. The Joliot-Curies had missed fission, too, refusing to consider the possibility that uranium was splitting into smaller atoms. Even Enrico Fermi’s team at the University of Rome, which in 1934 had pioneered the bombardment of uranium with neutrons, had overlooked the fissions occurring in their experimental apparatus. After the German announcement, physicists everywhere realized that the signals had come from fissioning uranium atoms.
After a few days of self-recrimination, Seaborg came to terms with the discovery. “What an exciting specialty I’d chosen,” he decided. “What great fortune to be in a field with so much work to be done.”
JUST A FEW WEEKS EARLIER, in the lobby of the King’s Crown Hotel in New York City, two émigré European scientists living in the United States met each other for the first time. If Seaborg’s decision to go into science was one of the keys to the launch of Hanford, that meeting was the other.
One of the two men was Enrico Fermi—at that point, with the possible exception of Albert Einstein, the best-known physicist in the world. Fermi was perhaps the last great physicist who was equally skilled as a theoretician and an experimentalist. Earlier in the decade, as a young professor at the University of Rome, he had developed a theory that explains radioactive decay, proposing that it results from a force in nature different from gravity or electromagnetism. He and his colleagues at the university were also the first to use neutrons to convert elements into radioactive isotopes, discovering in the process that slowly moving neutrons are especially effective in reconfiguring the neutrons and protons in nuclei. Fermi was a star in Italy, surrounded by skilled colleagues, lauded by the media, honored by Mussolini.
But Fermi’s wife Laura, the smart, beautiful, and elegant daughter of an admiral in the Italian Navy, was Jewish, which made their two children Jewish. By 1938, Mussolini’s growing anti-Semitism had made it impossible for the Fermis to remain in Italy. That year, Fermi won the Nobel Prize in Physics for his work on slow neutrons. He and his family used the trip to Stockholm, plus an eagerly offered visiting professorship at Columbia University, as a way to depart from Italy without raising suspicions that they were leaving for good. After the award ceremony they traveled to England and then to New York City, where they took rooms in the King’s Crown while looking for an apartment to rent. They were right to flee. During the war, Laura’s father was sent to a concentration camp and never heard from again.
The other man in the lobby of the King’s Crown was Leo Szilard, the oldest child of an assimilated Jewish upper-middle-class family in Budapest. During graduate school in Berlin, Szilard had written a dissertation on the connection between information theory and thermodynamics that attracted widespread attention, including from Albert Einstein. But he was never interested in becoming an academic scientist. Szilard’s interests were wide ranging, from physics and biology to history, literature, and politics, and he rarely stuck with a singl
e subject for long. Instead, he drifted from topic to topic, from city to city, and eventually from country to country. He stitched together projects and sources of income, often as a part-time or short-term researcher at universities where he knew someone with influence. He lived in hotels, in faculty residences, and, when worse came to worst, with friends. He never seemed to care much about his circumstances. For Szilard, only ideas mattered.
In 1933, Szilard was living at the Imperial Hotel in the Bloomsbury neighborhood of London and running an organization that he had cofounded to help refugee scholars escape from Nazi Germany. He was always adept at forecasting future developments and predicted, well before most people, that the rise of Hitler would lead Germany to war. On September 12, he read an article in The Times in which the physicist Ernest Rutherford was quoted as saying that anyone predicting the generation of energy from atomic nuclei was “talking moonshine.” The comment irritated Szilard. “How can anyone know what someone else might invent?” A few days later he was going for a walk in the neighborhood when he stopped for a red light at a crosswalk near the hotel. When the light turned green and he stepped off the curb, he thought of something. If an element could be found that released two neutrons when it was hit by one neutron, that element could create a chain reaction and release nuclear energy, thereby proving Rutherford wrong. Fission would not be discovered for another five years, and Szilard did not think right away of uranium as a chain reaction candidate. Still, in stepping off that curb, he conceived of one of the most important scientific ideas of the 20th century.
