Manhattan Project scientist Robert Serber, 88, died Sunday, 1 June 1997, at his home on the Upper West Side in Manhattan of complications following surgery for brain cancer.
Born March 14, 1909, in Philadelphia, Serber earned a bachelor's degree from Lehigh University in Bethlehem, Pa., in 1930 and a doctorate in physics at the University of Wisconsin in 1934. On his way for post-doctoral study at Princeton University, he stopped at the University of Wisconsin at Ann Arbor, where he heard Oppenheimer give a guest lecture.
He as so impressed that he instead moved to the University of California, Berkeley, to work with J. Robert Oppenheimeras as one of his protˇgˇs. He later became an associate professor at the University of Illinois, a job he held when Oppenheimer, his friend and mentor, asked him to join him on the Manhattan Project (Serber in fact moved into Oppenheimer's house for a year). From the summer of 1942 until March 1943, "Oppy and I were the Los Alamos project so far as theory was concerned," Serber once said.
During the summer of 1942 many of the basic principles of fission bomb physics and design were worked out. Serber developed the first good theory of bomb disassembly hydrodynamics (Nobel laureate PM Dirac had previously made an erroneous analysis of it). As a result the exponential shock wave was termed "the Serber shock" at the time.
In April 1943, when scientists were first gathering at Los Alamos, in New Mexico, Serber presented a series of five lectures which summarized all that was known at the time about designing and building an atomic bomb (mostly Serber's own work). His notes for those introductory sessions became the "Los Alamos Primer," the laboratory's first techical report (LA-1)*. The lectures were classified for 20 years after World War II ended and were published for the first time in 1992 by the University of California Press.
*This report, with annotations and commentary by Serber, and an introduction by Richard Rhodes, is currently available in hardcover as The Los Alamos Primer - The First Lectures on How to Build an Atomic Bomb from the University of California Press. A copy of the original report can be downloaded in Acrobat (.pdf) format (3.1 MB) from: http://lib-www.lanl.gov/la-pubs/00349710.pdf.
Serber's first wife, Charlotte, who died in 1967, was appointed by Oppenheimer to head Los Alamos' library, making her the only female section leader at wartime Los Alamos.
Serber worked extensively on the problems of neutron transport theory at Los Alamos, a very difficult area that was essential for designing fission bombs, and for predicting their performance. A mathematical technique he developed with Robert Wilson, deemed the Serber-Wilson method, was the primary means for performing criticality calculations for nuclear weapons during the war, and for some years afterward.
Serber had a remarkable ability to connect the work of other theoreticians into an intelligible structure, and to explain it lucidly to theoreticians and non-theoreticians alike. This made Serber an invaluable resource at Los Alamos, and he performed much the same service after the war, pulling the many threads of theory together for experimentalists at leading particle physics centers nationwide so their work could be more fruitful.
"He was an almost ideal bridge between the theoretical and experimental communities," Dr. Wolfgang Panofsky, the retired director of the Stanford Linear Accelerator Center, said in an interview. "Other theorists may have made more fundamental contributions, but they simply did not interact with the experimentalists as he did." Serber's talent was being able to comprehend a theory at its widest and narrowest points and to communicate that information to others, Panofsky said.
Serber was too interested in the nuts and bolts of how physics research was done to be a "super-highbrow theorist," Panofsky said. He was fascinated by the "gadgets" of experimental physics and "understood what made them tick," Panofsky added.
That practicality meant that Serber's role in the atomic bomb project did not end when the weapon was successfully tested on July 16, 1945. By the end of that month, Serber was sent to Tinian Island, in the Marianas in the South Pacific, where atomic bombs were being prepared, to provide quick advice about any changes that had to be made, to advise the military, and to reassure the air crews that would drop them.
Col. Paul Tibbets, the pilot of the plane that dropped the atomic bomb on Hiroshima, asked Serber if he and his crew would survive the blast, Serber wrote in an account in The Sciences magazine in 1995, so Serber did some quick calculations. "I did not know much about planes, but I assured him that he and the Enola Gay would be safe," Serber wrote.
Serber attended the Aug. 6, 1945, briefing for the Hiroshima mission, and he was "overjoyed" the next morning to hear that the mission had been a success.
Three days later, Serber was aboard one of the planes for the Nagasaki bombing mission; his job was to take photographs. The plane was rolling down the runway when the pilot called for a parachute check.
"We were one parachute short -- mine," Serber wrote. "The supply sergeant had neglected to give me one. The pilot ordered me put off the plane. That was truly idiotic: the mission of the plane was to take pictures, and I was the only one aboard who knew how to run the camera." But it did not matter in the end, he said; the pilot of that plane missed the rendezvous spot and was late in getting to Nagasaki. The tail gunner took a photograph of the mushroom cloud with a snapshot camera.
In early September 1945, he was with the first American team to enter Hiroshima and Nagasaki to assess the damage from the atomic bombs. He was in Japan for five weeks to assess the damage and to collect debris for tests. Serber and the other scientists measured radiation levels and recorded the damage. From shadows that had been burned into walls by the blast, Serber was able to calculate how high the bomb had been when it had exploded and how large the fireball had been.
While that trip gave Serber a first-hand view of the devastation, he remained convinced that the use of atomic weapons against Japan had been necessary to save the lives that would have been lost in an invasion. "Oppie had told me that the medical corps was prepared for half a million casualties, and I had no reason to doubt him," Serber wrote in 1995 in The Sciences, an article written with Dr. Robert P. Crease, a historian at Brookhaven National Laboratory on Long Island. "My thoughts about the wisdom of using the atomic bomb to bring a quick end to the war have not changed a bit since then."
While he later became an advocate of arms control, he never became an outspoken critic of nuclear weapons, as did some other Manhattan Project scientists.
After the war, he employed his talents at synthesis and explanation to gave a well-known series of lectures at the University of California at Berkeley, later distributed in mimeographed form as "Serber Says," to bring experimental physicists up to speed on nuclear theory so they could branch out in new directions in peacetime research.
Shortly after his return to Los Alamos, he left to work at the University of California's Radiation Laboratory in Berkeley. "The war was over and the work at Berkeley seemed much more exciting and compelling," Serber told the LANL Newsbulletin in a 1993 interview, conducted while he was at the Lab attending a Nuclear Weapons Technology seminar series to commemorate the Lab's 50th anniversary. "I also had no great foresight about Los Alamos, although I expected it to continue as a weapons laboratory."
Serber became a professor at Berkeley. He moved to Columbia University in 1951, at least in part, Panofsky said, because he objected to taking the oath of loyalty to the United States that was required of California professors. Starting as a professor of physics at Columbia, ge became chair of the physics department in 1975, retired from Columbia in 1978, and later was named a professor emeritus at the university.
Serber was one of the Manhattan Project scientists whose loyalty was questioned after the war, Crease said. He was cleared at a security hearing in 1948, but he was denied a security clearance in 1952 needed to attend a physics conference in Japan, Crease said. That angered him so much that he refused to join an advisory group put together by Dr. Edward Teller to advise the Department of Defense.
Charlotte Serber died in 1967. Serber is survived by the former Fiona St. Clair, whom he married in 1979, and by two sons, Zachariah and William, who are both studying in Edinburgh.
By Carey Sublette, with material adapted from the LANL Daily News Bulletin 3 June 1997