Sidney D. Drell, a physicist who served for nearly half a century as a top adviser to the United States government on military technology and arms control, died on Wednesday at his home in Palo Alto, Calif. He was 90.
His death was confirmed by his daughter Persis Drell.
Dr. Drell combined groundbreaking work in particle physics — he was deputy director of the Stanford Linear Accelerator Center, now the SLAC National Accelerator Laboratory, for nearly 30 years — with a career in Washington as a technical adviser and defense intellectual.
In 2000, he was given the Enrico Fermi Award for his life’s work, and in 2013, President Obama presented him with the National Medal of Science for his contributions to physics and his service to the government.
Beginning in 1960, as the Cold War heated up, Dr. Drell served on a succession of advisory groups that helped advance the technology of nuclear detection and shape the policy of nuclear deterrence.
As a founding member of the Jason defense advisory group, a panel of defense scientists, he helped develop the McNamara Line, a barrier that was intended to halt the infiltration of soldiers and weapons into South Vietnam from the north through a system that combined electronic surveillance with mines and troop concentrations at strategic points.
Dr. Drell was a strong proponent of nuclear deterrence during the Cold War. “I believed that given the Soviet empire, its stated goals and existence, we had to deter them,” he said in an interview for “The Partnership: Five Cold Warriors and Their Quest to Ban the Bomb” (2012), a book by Philip Taubman, a former reporter and editor for The New York Times.
“We had to be clear,” he added. “These are not weapons we want to use, but they have to know that should they monkey around with us, they had to expect we’re going to use them against them, and at a degree that’s unacceptable to them.”
At the same time, he was a leading advocate of arms control and a critic of major projects such as the MX missile and the Strategic Defense Initiative, the Reagan administration program also known as Star Wars.
Dr. Drell was recruited as a consultant for the Arms Control and Disarmament Agency soon after its creation in 1961 and served as a director of the Center for International Security and Arms Control (now the Center for International Security and Cooperation) at Stanford University in the 1980s. In 2006, he and George P. Shultz, the secretary of state under Ronald Reagan, founded a program at the Hoover Institution to propose practical steps to rid the world of nuclear weapons.
“In dealing with terrorists or rogue governments, nuclear deterrence doesn’t mean anything — the value has gone,” he told the website In Menlo in 2012. “Yet the danger of the material getting into evil hands has gone up. So what are existing nuclear arms deterring now? In this era, I argue that nuclear weapons are irrelevant as a deterrence.”
Sidney David Drell was born on Sept. 13, 1926, in Atlantic City, to Jewish immigrants from the Russian empire. His father, Tully, was a pharmacist. His mother, the former Rose White, was a teacher.
He was admitted to Princeton at 16 and earned a degree in physics in 1946. At the University of Illinois, he obtained a master’s degree in physics in 1947 and a doctorate in 1949.
After teaching at Stanford for two years, he joined the physics department at the Massachusetts Institute of Technology. He left in 1956 to work under Wolfgang K. H. Panofsky at the Stanford Linear Accelerator Center.
As an academic, Dr. Drell specialized in quantum electrodynamics, which describes the interactions between light and matter, and quantum chromodynamics, which explores subatomic particles like quarks and gluons.
He and Tung-Mow Yan, a research associate at the accelerator center, formulated a key concept in particle physics when they explained what happens when a quark in one particle collides with an antiquark in a second particle, an annihilating confrontation that yields an electron and a positron. The sequence of events became known as the Drell-Yan process.
Dr. Drell was the author of “Electromagnetic Structure of Nucleons” (1961) and, with the theoretical physicist James D. Bjorken, wrote the textbooks “Relativistic Quantum Mechanics” (1964) and “Relativistic Quantum Fields” (1965).
As the head of the theory group at the accelerator center, which gathered leading scientists to discuss nuclear science, he found himself in demand as a technical adviser on defense and security.
In 1960, Dr. Drell was invited to join an advisory group led by Charles H. Townes, the father of the laser. His task was to see whether orbiting infrared sensors could detect a Soviet intercontinental missile launch by picking up a heat reading from the missile’s exhaust plume. Additionally, he had to determine whether the Soviet Union could nullify the sensors by exploding a nuclear device in the atmosphere before the main launch.
After he and his team judged such an explosion impractical, the Defense Department went ahead with plans to develop the Missile Defense Alarm System.
He later served on the Land Panel, which developed a new system for taking high-resolution, wide-range photographs from spy satellites.
During the Vietnam War, Dr. Drell’s service on the President’s Science Advisory Committee under Lyndon B. Johnson and Richard M. Nixon, and his role as a shadow adviser to Henry A. Kissinger, damaged his academic reputation as opinion turned against American policy. Increasingly, he found himself fending off attacks in public forums.
“Call it entrapment, commitment or whatever, but I have remained actively involved in technical national security work for the United States,” he told Mr. Taubman.
After the war, he emerged as a leading thinker on arms control and disarmament, which he addressed in numerous books and papers, including “Facing the Threat of Nuclear Weapons” (1983), “The Reagan Strategic Defense Initiative: A Technical, Political and Arms Control Assessment” (1985), “In the Shadow of the Bomb: Physics and Arms Control” (1993) and “The Gravest Danger: Nuclear Weapons” (2003).
In addition to his daughter Persis, who directed Stanford’s accelerator laboratory for five years, he is survived by his wife of 64 years, the former Harriet Stainback; another daughter, Joanna Drell; a son, Daniel, and three grandchildren.
Correction: December 23, 2016
An earlier version of this obituary omitted two of Dr. Drell’s survivors. They are his wife, the former Harriet Stainback, and his son, Daniel. It also misstated his position at the Stanford Linear Accelerator Center. He was deputy director, not the director.