Otto Frisch

Otto Frisch was an Austrian-born British physicist who played a pivotal role in the discovery and understanding of nuclear fission. With his aunt, Lise Meitner, he provided the first theoretical explanation for the results of Otto Hahn and Fritz Strassmann's experiments, coining the term "fission" in the process. His later work on the Frisch–Peierls memorandum was crucial in jump-starting the Allied atomic bomb project, leading to his significant contributions to the Manhattan Project.

Early life and education

Born in Vienna to a family of Jewish intellectuals, his father was a painter and his mother a concert pianist. He displayed an early aptitude for science and mathematics, enrolling at the University of Vienna to study physics. Under the supervision of Karl Przibram, he earned his doctorate in 1926 with work on the photoelectric effect under the influence of Salomon Rosenblum. Following his graduation, he held research positions at the Physikalisch-Technische Bundesanstalt in Berlin under Otto Stern and later at the University of Hamburg, where he collaborated with Emilio Segrè and Patrick Blackett.

Work on nuclear physics

The rise of the Nazi Party in 1933 forced him to leave Germany, leading to a five-year fellowship at the University of Copenhagen under the mentorship of Niels Bohr. It was during a 1938 Christmas visit to his aunt, Lise Meitner, in Kungälv, Sweden, that he learned of the puzzling results from Otto Hahn's laboratory at the Kaiser Wilhelm Institute for Chemistry in Berlin. He and Meitner famously discussed the problem during a walk in the snow, where they conceived the idea of the nucleus splitting, which he later named "fission" by analogy with biological cell division. Their joint paper, "Disintegration of Uranium by Neutrons: A New Type of Nuclear Reaction," was published in the journal Nature in 1939.

Manhattan Project and later career

At the outbreak of World War II, he was visiting the University of Birmingham in England and was detained as an enemy alien. Upon release, he joined the laboratory of Mark Oliphant, where he collaborated with fellow refugee physicist Rudolf Peierls. Together, they calculated the critical mass of uranium-235, proving a practical atomic bomb was feasible. Their secret report, the Frisch–Peierls memorandum, was a direct catalyst for the establishment of the MAUD Committee and, ultimately, the Manhattan Project. He subsequently joined the British Mission to the project, working primarily at the Los Alamos Laboratory in the New Mexico desert under the direction of J. Robert Oppenheimer, where he led the critical assembly group for the Trinity test device. After the war, he returned to England, first heading the nuclear physics division at the Atomic Energy Research Establishment at Harwell and then becoming the Jacksonian Professor of Natural Philosophy at the University of Cambridge and a fellow of Trinity College, Cambridge.

Personal life and legacy

He married artist Ursula Blau in 1951, and they had one son and one daughter. A talented pianist and skilled draftsman, he was known for his clarity of thought and engaging lecture demonstrations. He was elected a Fellow of the Royal Society in 1948 and received numerous honors, including the Max Planck Medal from the German Physical Society. His popular science book, What Little I Remember, provides a witty and insightful account of the golden age of nuclear physics. He died in Cambridge in 1979, remembered as a key experimentalist and theorist whose insights helped usher in the nuclear age.

Category:Austrian physicists Category:Manhattan Project people Category:Fellows of the Royal Society Category:1904 births Category:1979 deaths