Martin D. Kamen, whose discovery of the element carbon-14 made it possible for biologists to decipher the complex chemistry of the living cell, died Aug. 31 at his home in Montecito. The chemist, an emeritus professor at both UC San Diego and USC, died four days after his 89th birthday.
“Without carbon-14, biochemistry as we know it today just wouldn’t exist,” said UC San Diego chemist Bruno Zimm.
The discovery also made possible the radiocarbon dating that allows archeologists to determine the age of artifacts dating back 50,000 years, allowing the creation of precise timelines for early civilizations.
Kamen was working with Ernest O. Lawrence at UC Berkeley when he and Samuel Ruben made the carbon-14 discovery in 1940, but he later lost his position in the Communist witch hunts of World War II. His passport was revoked, he was summoned before the House Un-American Activities Committee and, in 1951, the Chicago Tribune and the Washington Times-Herald publicly labeled him a suspected spy. At his nadir, he even attempted suicide--one of the few failures in his life.
The charges proved groundless, however. He got his passport back, sued the newspapers for libel and won, and in 1995 received the Enrico Fermi Award for his pioneering contributions to physics. Colleagues say that he should have received the Nobel Prize as well because his discovery was crucially important to so many areas of science.
“They’re making amends, which is better than what they would do in Russia,” Kamen said at the time of his award. “It’s vindication ... but I’ve spent 55 years toward that end in building my career.”
Kamen was born in Toronto in 1913, the son of Jewish immigrants. Naturally brilliant, he was a child prodigy on the violin--a fact that scarred the rest of his life.
“I was [always] the center of attention,” Kamen told interviewers later. “Whenever there were family gatherings, I was expected to perform and my cousins hated me. Everyone was out to get me. When nobody was looking, I got beat up.” That experience often led him to denigrate his accomplishments. “I don’t want to be singled out. I didn’t want to be a soloist.”
As a teenager, he switched to the viola, the better to remain in the background. He remained an accomplished musician throughout his career, often playing with well-known performers.
After graduate school at the University of Chicago, he joined UC Berkeley, where Lawrence ultimately launched him on the search for a new isotope of carbon. Radioisotopes played a crucial role in deciphering chemical processes within the cell. By labeling a sugar molecule, for example, with carbon-11 molecules, biochemists could track its progress through the cell, identifying the individual chemicals it is sequentially converted into as the body burns it for energy.
But carbon-11 is short-lived--half of it disappears every 21 minutes. “By the time you have set up to do a reaction, it has disappeared,” Zimm said. Using the 60-inch cyclotron at Berkeley, Kamen and Ruben bombarded a graphite target with a beam of deuterium nuclei, eventually producing enough carbon-14 for identification. It suited scientists’ needs perfectly because it had a half-life of 5,730 years, much longer than had been predicted by theory.
Typically, Kamen allowed most of the credit for the discovery to go to Ruben, who was killed not long afterward when he inhaled phosphene in a laboratory accident.
Physicists soon discovered that carbon-14 is produced naturally when the atmosphere is bombarded by cosmic rays. Plants incorporate this radioactive isotope as they grow, so its concentration in their tissues is the same as its concentration in the atmosphere. But when the plant dies, no more carbon-14 is taken in and the small amount present begins to decay, converting into nitrogen-14.
In 1949, chemist Willard Libby of the University of California made use of this discovery to invent radiocarbon dating.
Kamen was a liberal, a political leaning that brought many scientists under suspicion during the war years. While he was working on the Manhattan Project at Tennessee’s Oak Ridge National Laboratory, he incurred further suspicion when he correctly deduced that the project had already built a nuclear reactor, even though he was not cleared to know about it.
His downfall came after a 1944 dinner with two Soviet officials he had met at a party given by violinist Isaac Stern, with whom he occasionally played. The Russians asked him about radiation treatments for a colleague with leukemia. FBI agents suspected a more sinister motive, and Kamen was fired the next day.
For nine months, the only job he could get was as an inspector in a shipyard. Ultimately, however, he was hired by Washington University in St. Louis. He later became a founding faculty member at UC San Diego and taught at USC. During the 1950s and 1960s, he did groundbreaking research on bacterial cytochromes and photosynthesis, but he is remembered primarily for his research on carbon-14.
Kamen’s marriage to his first wife, Esther, ended in divorce in 1943. His second wife, Beka, died in 1963 and his third, Virginia, died in 1987. He is survived by his son, David, a U.N. translator in New York City, and a sister, Lillian Smith of Chapel Hill, N.C.