Wolfgang Panofsky, known to his friends and colleagues as “Pief”, was a renowned nuclear physicist and a very effective administrator. The breadth of his career was remarkable. As a nuclear physicist, he was best known for his crucial discoveries about the nature of the neutral pi meson (pion), a member of the family of elementary particles. Elementary particles are fundamental constituents of all matter. They include — in addition to mesons — neutrons, protons, electrons and others.

Hideki Yukawa, the Japanese 1949 Nobel prize-winning physicist, predicted the existence of mesons theoretically in 1935. In 1947 Cecil Powell, the British 1950 Nobel prize-winning physicist, and his collaborators at Bristol University, discovered tracks of charged pions in photographic emulsions placed for a long time in sites located at high altitude on mountains (at Pic du Midi de Bigorre in the Pyrénées and later at Chacaltaya in the Andes). These pions carried an electrical charge.

Neutral pions are much more difficult to observe than charged pions; they do not leave tracks in a photographic emulsion. Neutral pions are normally produced in machines that accelerate particles, like cyclotrons and electron accelerators. They were first produced and identified at the Berkeley cyclotron in 1950. The neutral pion exists for a very short time indeed and then decays into two gamma rays.

Panofsky was the leading light in the creation of an electron accelerator, more than three kilometres (two miles) long built at Stanford University, Palo Alto, California, which accelerated electrons to very high speeds. The accelerator was used as a research tool in particle physics. As a researcher, a builder of machines and an administrator of basic nuclear physics research, Panofsky had a considerable impact on the development of particle physics.

In addition to his career as a scientist, he advocated, throughout his life, the control of the nuclear arms race and took a keen interest in American and international security policy. During the 1980s he was a strong and outspoken critic of the Strategic Defence Initiative, proposed by President Reagan on March 23, 1983, to use ground and space-based systems to protect the territory of the US against attack from strategic ballistic missiles — the “Star Wars” anti-ballistic missile programme.

He became an influential government adviser, spending much time in Washington trying to influence the US Government in the development of its security policy. In parallel with this, he helped to develop the science policies of the US Government.

He also worked, during the height of the Cold War, to establish a dialogue between the Soviet Union and the West. In particular, he used contacts with senior Soviet and Western scientists to persuade them to explain to the political leaders, on both sides, the dangers of the nuclear arms race and the risk of an all-out nuclear war.

Wolfgang Kurt Hermann Panofsky was born in 1919 in Berlin. He spent much of his early life in Hamburg, where his father, Erwin Panofsky, was a professor of art history. In 1934 the family moved to the US to escape the Nazi persecution of the Jews. Erwin Panofsky became Professor of Art History at the Institute of Advanced Study, Princeton University, New Jersey.

Wolfgang Panofsky became a student at Princeton University, studying physics, mathematics and Latin. He received his bachelor’s degree in 1938 and then went to the California Institute of Technology, Pasadena, California, as a postgraduate student, obtaining his PhD in 1942. He became an American citizen in the same year.

In 1942 and 1943 he was director of the Office of Scientific Research and Development Project at the California Institute of Technology. Between 1943 and 1945 he was a consultant to the Manhattan Project at Los Alamos, New Mexico, helping to develop the first atomic bomb.

In 1945-46 he worked as a physicist at the Radiation Laboratory, University of California at Berkeley. In 1951 he became an assistant professor and then associate professor at the University of California at Berkeley. He then went to Stanford University as a professor of physics, directing the university’s high-energy physics laboratory.

Between 1961 (when the project to build the electron accelerator began) and 1984, he was the director of the Stanford Linear Accelerator Centre (SLAC) and continued to serve as its director Emeritus after he retired in 1984.

He remained active at SLAC until the last day of his life. During his directorship, three Stanford scientists won Nobel prizes for their discoveries of new elementary particles.

His work on the Manhattan Project and the destruction in 1945 of Hiroshima and Nagasaki by atomic bombs had a profound influence on Panofsky’s thinking about the ethical and social responsibilities of scientists.

He was a member of the US President’s Science Advisory Committee in the Eisenhower, Kennedy and Johnson administrations. He encouraged the negotiation of the 1963 Treaty Banning the Testing of Nuclear Weapons in the Atmosphere (the Partial Test Ban Treaty) and of the 1972 Anti-Ballistic Missile Treaty. He later helped to establish the Centre for International Security and Arms Control at Stanford University which became a very influential think-tank on arms control and international security issues.

Panofsky received a large number of awards and honours. In 1969 he was awarded the US National Medal of Science by President Nixon. In addition, he received the Ernest Orlando Lawrence Memorial Award (1961), the Franklin Institute Award (1970), the Enrico Fermi Award (1979), the Leo Szilard Award (1982), the Matteucei Medal (Rome, 1997) and the International Scientific and Technological Award from the People’s Republic of China (2001). He was made an Officer of the French Legion of Honour in 1977.

He was a member of the US National Academy of Sciences (1954), the American Academy of Arts and Sciences, the American Physical Society (president 1974), and the American Philosophical Society.

He was an elected foreign member of the Chinese Academy of Sciences (2002), the Académie des Sciences (France, 1989), the Accademia Nazionale dei Lincei (Italy) and the Russian Academy of Sciences.

He was awarded honorary degrees by four American universities, two German universities and universities in Canada, Italy, the People’s Republic of China and Sweden.

His autobiography, Panofsky on Physics, Politics and Peace: Pief Remembers, is published this month.

Panofsky was known for his considerable integrity, the warmth of his personality, his belief in high principles and his willingness to fight for them.

He is survived by his wife and five children.

Wolfgang Panofsky, nuclear physicist, was born on April 24, 1919. He died on September 24, 2007, aged 88