Frederick Reines ( RY-nəs; March 16, 1918 – August 26, 1998) was an American physicist. He was awarded the 1995 Nobel Prize in Physics for his co-detection of the neutrino with Clyde Cowan in the neutrino experiment. He may be the only scientist in history "so intimately associated with the discovery of an elementary particle and the subsequent thorough investigation of its fundamental properties."
A graduate of Stevens Institute of Technology and New York University, Reines joined the Manhattan Project's Los Alamos Laboratory in 1944, working in the Theoretical Division in Richard Feynman's group. He became a group leader there in 1946. He participated in a number of nuclear tests, culminating in his becoming the director of the Operation Greenhouse test series in the Pacific in 1951.
In the early 1950s, working in Hanford and Savannah River Sites, Reines and Cowan developed the equipment and procedures with which they first detected the supposedly undetectable neutrinos in June 1956. Reines dedicated the major part of his career to the study of the neutrino's properties and interactions, which work would influence study of the neutrino for many researchers to come. This included the detection of neutrinos created in the atmosphere by cosmic rays, and the 1987 detection of neutrinos emitted from Supernova SN1987A, which inaugurated the field of neutrino astronomy.
Frederick Reines was born in Paterson, New Jersey, one of four children of Gussie (née Cohen) and Israel Reines. His parents were Jewish emigrants from the same town in Russia, but only met in New York City, where they were later married. He had an older sister, Paula, who became a doctor, and two older brothers, David and William, who became lawyers. He said that his "early education was strongly influenced" by his studious siblings. He was the great-nephew of the Rabbi Yitzchak Yaacov Reines, the founder of Mizrachi, a religious Zionist movement.
The family moved to Hillburn, New York, where his father ran the general store, and he spent much of his childhood. He was an Eagle Scout. Looking back, Reines said: "My early childhood memories center around this typical American country store and life in a small American town, including Independence Day July celebrations marked by fireworks and patriotic music played from a pavilion bandstand."
Reines sang in a chorus, and as a soloist. For a time he considered the possibility of a singing career, and was instructed by a vocal coach from the Metropolitan Opera who provided lessons for free because the family did not have the money for them. The family later moved to North Bergen, New Jersey, residing on Kennedy Boulevard and 57th Street. Because North Bergen did not have a high school, he attended Union Hill High School in Union Hill, New Jersey (today Union City, New Jersey), from which he graduated in 1935.
From an early age, Reines exhibited an interest in science, and liked creating and building things. He later recalled that:
The first stirrings of interest in science that I remember occurred during a moment of boredom at religious school, when, looking out of the window at twilight through a hand curled to simulate a telescope, I noticed something peculiar about the light; it was the phenomenon of diffraction. That began for me a fascination with light.
Ironically, Reines excelled in literary and history courses, but received average or low marks in science and math in his freshman year of high school, though he improved in those areas by his junior and senior years through the encouragement of a teacher who gave him a key to the school laboratory. This cultivated a love of science by his senior year. In response to a question seniors were asked about what they wanted to do for a yearbook quote, he responded: "To be a physicist extraordinaire."
Reines was accepted into the Massachusetts Institute of Technology, but chose instead to attend Stevens Institute of Technology in Hoboken, New Jersey, where he earned his Bachelor of Science (B.S.) degree in mechanical engineering in 1939, and his Master of Science (M.S.) degree in mathematical physics in 1941, writing a thesis on "A Critical Review of Optical Diffraction Theory". He married Sylvia Samuels on August 30, 1940. They had two children, Robert and Alisa. He then entered New York University, where he earned his Doctor of Philosophy (Ph.D.) in 1944. He studied cosmic rays there under Serge A. Korff, but wrote his thesis under the supervision of Richard D. Present on "Nuclear fission and the liquid drop model of the nucleus". Publication of the thesis was delayed until after the end of World War II; it appeared in Physical Review in 1946.
In 1944 Richard Feynman recruited Reines to work in the Theoretical Division at the Manhattan Project's Los Alamos Laboratory, where he would remain for the next fifteen years. He joined Feynman's T-4 (Diffusion Problems) Group, which was part of Hans Bethe's T (Theoretical) Division. Diffusion was an important aspect of critical mass calculations. In June 1946, he became a group leader, heading the T-1 (Theory of Dragon) Group. An outgrowth of the "tickling the Dragon's tail" experiment, the Dragon was a machine that could attain a critical state for short bursts of time, which could be used as a research tool or power source.
Reines participated in a number of nuclear tests, and writing reports on their results. These included Operation Crossroads at Bikini Atoll in 1946, Operation Sandstone at Eniwetok Atoll in 1948, and Operation Ranger and Operation Buster–Jangle at the Nevada Test Site. In 1951 he was the director of Operation Greenhouse series of nuclear tests in the Pacific. This saw the first American tests of boosted fission weapons, an important step towards thermonuclear weapons. He studied the effects of nuclear blasts, and co-authored a paper with John von Neumann on Mach stem formation, an important aspect of an air blast wave.
In spite or perhaps because of his role in these nuclear tests, Reines was concerned about the dangers of radioactive pollution from atmospheric nuclear tests, and became an advocate of underground nuclear testing. In the wake of the Sputnik crisis, he participated in John Archibald Wheeler's Project 137, which evolved into JASON. He was also a delegate at the Atoms for Peace Conference in Geneva in 1958.
Discovery of the neutrino and the inner workings of stars
The neutrino is a subatomic particle first proposed by Wolfgang Pauli on December 4, 1930. The particle was required to resolve the problem of missing energy in observations of beta decay, when a neutron decays into a proton and an electron. The new hypothetical particle was required to preserve the fundamental law of conservation of energy. Enrico Fermi renamed it the neutrino, Italian for "little neutral one", and in 1934, proposed his theory of beta decay by which the electrons emitted from the nucleus were created by the decay of a neutron into a proton, an electron, and a neutrino:
The neutrino accounted for the missing energy, but Fermi's theory described a particle with little mass and no electric charge that appeared to be impossible to observe directly. In a 1934 paper, Rudolf Peierls and Hans Bethe calculated that neutrinos could easily pass through the Earth, and concluded "there is no practically possible way of observing the neutrino."
In 1951, Reines and his colleague Clyde Cowan decided to see if they could detect neutrinos and so prove their existence. At the conclusion of the Greenhouse test series, Reines had received permission from the head of T Division, J. Carson Mark, for a leave in residence to study fundamental physics. "So why did we want to detect the free neutrino?" he later explained, "Because everybody said, you couldn't do it."
According to Fermi's theory, there was also a corresponding reverse reaction, in which a neutrino combines with a proton to create a neutron and a positron: