PRECISE KINETIC ENERGY MEASUREMENTS AND FINE STRUCTURE IN THE SPONTANEOUS FISSION OF Cf²⁵²

Abstract

The kinetic energies of the fragments from spontaneous fission of Cf 252 have been remeasured in order to provide reliable data for the calibration of semiconductor detectors. The results, which are in satisfactory agreement with a recent measurement by Whetstone (1963), are presented in a convenient form for the energy calibration of semiconductor detectors by means of a least-squares fitting procedure. They are given before and after neutron emission. A fine structure is seen in the mass–energy contour diagram in the region of low fragment excitation energy. As in the slow-neutron-induced fission of lighter elements there are periodic yield maxima at heavy fragment mass numbers of 134, 140, 146, and 152.