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Robert Serber

1909 - 1997

Manhattan Project scientist Robert Serber, 88, diedSunday, 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 earneda bachelor's degree from Lehigh University inBethlehem, Pa., in 1930 and a doctorate in physics atthe 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 movedto the University of California, Berkeley, to workwith 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 theManhattan 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 weaponsduring 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 theoreticaland experimental communities," Dr. Wolfgang Panofsky,the retired director of the Stanford Linear AcceleratorCenter, said in an interview. "Other theorists may havemade more fundamental contributions, but they simply didnot interact with the experimentalists as he did."Serber's talent was being able to comprehend a theory atits widest and narrowest points and to communicate thatinformation to others, Panofsky said.

Serber was too interested in the nuts and bolts of howphysics research was done to be a "super-highbrowtheorist," Panofsky said. He was fascinated by the"gadgets" of experimental physics and "understood whatmade them tick," Panofsky added.

That practicality meant that Serber's role in the atomic bomb project did not end when the weapon wassuccessfully tested on July 16, 1945. By the end of thatmonth, Serber was sent to Tinian Island, in theMarianas 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 droppedthe atomic bomb on Hiroshima, asked Serber if he and hiscrew would survive the blast, Serber wrote in an accountin The Sciences magazine in 1995, so Serber did somequick calculations. "I did not know much about planes,but I assured him that he and the Enola Gay would besafe," Serber wrote.

Serber attended the Aug. 6, 1945, briefing for theHiroshima mission, and he was "overjoyed" the nextmorning to hear that the mission had been a success.

Three days later, Serber was aboard one of the planesfor the Nagasaki bombing mission; his job was to takephotographs. The plane was rolling down the runway whenthe pilot called for a parachute check.

"We were one parachute short -- mine," Serber wrote."The supply sergeant had neglected to give me one. Thepilot ordered me put off the plane. That was trulyidiotic: the mission of the plane was to take pictures,and I was the only one aboard who knew how to run thecamera." But it did not matter in the end, he said; thepilot of that plane missed the rendezvous spot and waslate in getting to Nagasaki. The tail gunner took aphotograph of the mushroom cloud with a snapshot camera.

In early September 1945, he was with the firstAmerican team to enter Hiroshima and Nagasaki to assessthe 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 thedamage. 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 thedevastation, he remained convinced that the use ofatomic weapons against Japan had been necessary to savethe lives that would have been lost in an invasion."Oppie had told me that the medical corps was preparedfor half a million casualties, and I had no reason todoubt him," Serber wrote in 1995 in The Sciences, anarticle written with Dr. Robert P. Crease, a historianat Brookhaven National Laboratory on Long Island. "Mythoughts about the wisdom of using the atomic bomb tobring a quick end to the war have not changed a bitsince then."

While he later became an advocate of arms control, henever became an outspoken critic of nuclear weapons, asdid 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 nucleartheory so they could branch out in new directions inpeacetime research.

Shortly after his returnto Los Alamos, he left to work at the University of California's Radiation Laboratory in Berkeley. "Thewar 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 WeaponsTechnology 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. Hemoved to Columbia University in 1951, at least in part,Panofsky said, because he objected to taking the oath ofloyalty to the United States that was required ofCalifornia 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 theuniversity.

Serber was one of the Manhattan Project scientists whoseloyalty was questioned after the war, Crease said. Hewas cleared at a security hearing in 1948, but he wasdenied a security clearance in 1952 needed to attend aphysics conference in Japan, Crease said. That angeredhim so much that he refused to join an advisory groupput together by Dr. Edward Teller to advise theDepartment of Defense.

Charlotte Serber died in 1967. Serber is survived by theformer Fiona St. Clair, whom he married in 1979, and bytwo sons, Zachariah and William, who are both studyingin Edinburgh.

By Carey Sublette, with material adapted from the LANL Daily News Bulletin 3 June 1997