The 12C(p, p′3α) Breakup Reaction Induced by 14, 18 and 26 MeV Protons

Abstract

Double-differential cross sections (DDXs) of emitted protons and αs particles were measured for proton-induced reactions on 12C at 14, 18 and 26MeV in order to investigate the 12C(p, p′3α) breakup reaction. The experimental DDXs were analyzed on the assumption that the (p, p′3α) reaction proceeds through two major processes, a three-body simultaneous breakup (3BSB) process (i.e., p+12C→p+α+8Be*2094Mev) and sequential decay processes from unstable nuclei produced by (p, p′) and (p, α) reactions (i.e., 12C, 9B, 8Be and 5Li). Partial cross sections for the various reaction channels were extracted from the measured DDXs by a least squares method with two fitting functions: a three-body phase distribution function for the 3BSB process and a Breit-Wigner function for the transition to a discrete level in the first step of the sequential decay process. The result showed that the 12C(p, p′3α) reaction took place predominantly via nearly isotropic particle emission in the 3BSB process, and emission of protons and α particles with low energies was explained well by the sequential decay via 12C* and 9Bg.s Experimental (p, p) and (p, p′) scattering cross sections at 26 MeV were reproduced well by the coupled-channels calculation with the soft-rotator model. The experimental DDXs were compared with a Monte Carlo calculation based on the SCINFUL/DDX code and the latest intermediate energy nuclear data evaluation library LA150.