Martin Kamen; a Discoverer of Radioactive Carbon-14

Martin D. Kamen, one of the scientists who discovered radioactive carbon-14 and in doing so helped lay a foundation for deciphering the chemical processes in plants and animals, died on Aug. 31 at his home in Santa Barbara, Calif. He was 89.
"The whole world changed," said Dr. Arthur B. Robinson of the Oregon Institute of Science and Medicine, who was a doctoral student of Dr. Kamen. "Before that, nobody could make any progress with biochemistry."
Carbon-14 also revolutionized archaeology, allowing precise dating of bones and artifacts.
Dr. Kamen was unable to bask in recognition for the discovery, made in 1940. Four years later, he was summarily fired by the University of California at Berkeley, because of suspicions arising from a dinner he had with two officials from the Russian consulate. Over the next decade, he fought recurring rumors and accusations that he had leaked atomic bomb secrets.
At first, he found all academic positions closed to him and worked for a while as an inspector at a shipyard. The House Un-American Activities Committee summoned him to testify in 1948. The State Department refused to issue him a passport. The Chicago Tribune in 1951 published articles naming him as a suspected spy. He attempted suicide.
In his autobiography, "Radiant Science, Dark Politics" (1985), Dr. Kamen said his wife, Beka, found him lying on the bathroom floor, bleeding from cuts to his face and throat. "Fortunately," he wrote, "the knife I had seized had been dull."
In 1955, he won a lawsuit against The Tribune for libel, and the State Department finally relented with a passport.
"They made a mistake, and it was a terrible mistake," Dr. Robinson said. "The guy, if anything, was conservative for an academic."
In 1996, Dr. Kamen shared the Enrico Fermi Award, which recognizes lifetime achievements in energy research. The award is given by the United States Department of Energy, which runs the University of California laboratory that had fired him five decades earlier.
"He was aware of the irony," said Dr. Kamen's son, David. "He was happy to receive the award. It didn't particularly improve his view of government bureaucrats."
Born in Toronto, Martin David Kamen earned his bachelor's and doctoral degrees in chemistry and physical chemistry at the University of Chicago.
He started working at the radiation laboratory of Dr. Ernest O. Lawrence at the University of California at Berkeley in 1937. Dr. Kamen and Dr. Samuel Ruben, a chemist at the university, were interested in the chemical reactions of photosynthesis, hoping to trace the carbon-based molecules. Almost all carbon atoms in nature are carbon-12, meaning they contain 12 protons and neutrons in the nucleus.
If some of the stable carbon-12 atoms could be replaced with radioactive versions, then scientists could spot the locations of the molecules by the radiation they emitted. But the only known radioactive version of carbon was carbon-11, and half of it decays in only 20 minutes, which is known as its half-life. That limitation restricted scientists to experiments lasting only a few hours.
Even so, Dr. Kamen and Dr. Ruben were able to show that the oxygen produced by photosynthesis originates from water molecules, not carbon dioxide as had been supposed by some.
To search for longer-lived carbon isotopes, the two men bombarded graphite in the 60-inch cyclotron accelerator at the laboratory. The result was carbon-14, which has a half-life of 5,730 years.
Dr. Kamen's troubles began during the Manhattan Project. While assigned to a project in Tennessee at what is now Oak Ridge National Laboratory, he asked a colleague to produce some radioactive sodium that he needed for an experiment, he said in his autobiography.
When he opened the container with the sodium, he was surprised that it was glowing purple — much more radioactive than could be produced in a cyclotron. He immediately realized that an atomic reactor must have already been built at the laboratory, he wrote. Because of security, Dr. Kamen was not among those told of the reactor.
In his excitement, he blurted out his realization to Dr. Lawrence, who was visiting the laboratory, and to Dr. Lawrence's Army escort. "Lawrence strode on, dissembling any interest in the news," Dr. Kamen wrote, "but shortly afterward I heard that an investigation had been instituted to find out the source of the leak to me."
Later, back in California, Dr. Kamen met two Russian officials at a cocktail party given by the violinist Isaac Stern, a friend. The consulate vice counsel asked Dr. Kamen for help in obtaining experimental radiation treatment for a colleague with leukemia, Dr. Kamen said. He made inquiries. In appreciation, the official invited Dr. Kamen for dinner at Bernstein's Fish Grotto.
Because of the earlier incident at Oak Ridge, Federal Bureau of Investigation agents observed the dinner. Dr. Kamen was fired almost immediately.
With help from friends, Dr. Kamen became a professor of biochemistry at Washington University in St. Louis in 1945. He moved to Brandeis University in 1957 before becoming one of the founding faculty members at the University of California at San Diego in 1961.
His later research focused on large proteins known as cytochromes, which play an important part in photosynthesis for storing energy and in metabolism for converting food into energy.
Dr. Kamen's marriage to his first wife, Esther, ended in divorce in 1943. His second wife, Beka, died in 1963. His third wife, Virginia, died in 1987.
In addition to his son, David, Dr. Kamen is survived by a sister, Lillian Smith of Chapel Hill, N.C., and a grandson.
Dr. Kamen was also often accompanied by his viola. He had considered a musical career before shifting to science and continued to play. "Pretty much everywhere he went, his idea of a social evening was to play chamber music with good friends," said David Kamen. "He played with Isaac all the time."  

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