Origin of Protons in Californium-252 Fission

Protons from ²⁵²Cf fission have been studied to determine their origin by using a ΔE, E detector particle telescope. Both fission- and nonfission-related events are discussed as possible sources of the observed proton energy spectrum. The increased yield of low-energy protons, which peak at ∼3.2 MeV, seems to be due mainly to background (α,p) reactions. Evidence of polar proton emission is discussed and gives an estimated polar proton emission yield of 2.83 ± 0.18 × 10⁻⁵ per fission, with a most probable energy of 10.0 ± 0.2 MeV and full-width at half-maximum (FWHM) of 7.6 ± 0.2 MeV. The yield of tripartition fission-related protons was then estimated to be 3.50 ± 0.20 × 10⁻⁵ per fission, with a most probable energy of 6.6 ± 0.2 MeV and an FWHM of 7.0 ± 0.2 MeV