Petr Efimovich Spivak ( born 24.03.1911) is a Soviet experimental physicist and a corresponding member of the USSR Academy of Sciences (1964). He was born in St Petersburg. He graduated from the Leningrad Polytechnic Institute (1936). In 1936-43 he worked at the Leningrad Physico-Technical Institute, and from 1943 at the I. V. Kurchatov Institute of Atomic Energy (head of a laboratory from 1949).
His main work is in the fields of nuclear physics and the physics of weak interactions. Together with his colleagues he carried out a series of studies to determine the number of secondary neutrons per capture event in the fission of nuclei by thermal neutrons and by neutrons in the energy range 30 — 900 keV, and other nuclear-physics characteristics of fissile isotopes; to study the decay of the neutron and measure its half-life; and to measure the degree of longitudinal polarisation of electrons in beta decay.
USSR State Prize (1953). I. V. Kurchatov Gold Medal (1962).