An investigation of the three-body reaction He^3(He^3, 2p)He^4

Abstract

Reactions produced by the He3 bombardment of the He3 have been investigated for bombarding energies from 1 to 20 MeV using a tandem Van de Graaff accelerator. Proton spectra from the three-body reaction He3(He3, 2p)He4 have been measured with a counter telescope at 13 angles for 9 bombarding energies between 3 and 18 MeV. The results are compared with a model for the reaction which includes a strong p-He4 final-state interaction. Alpha-particle spectra have been obtained at 12 and 18 MeV for forward angles with a magnetic spectrometer. These spectra indicate a strongly forward-peaked mechanism involving the 1S0 p-p interaction in addition to the p-He4 interaction. Measurements of p-He4 and p-p coincidence spectra at 10 MeV confirm these features of the reaction mechanism. Deuteron spectra from the reaction of He3(He3, d)pHe3 have been measured at 18 MeV. A triton spectrum from the reaction He3(He3, t)3p at 20 MeV and 40 is interpreted in terms of a sequential decay through an excited state of the alpha particle at 20.0 MeV. No effects are observed which would indicate an interaction in the residual (3p) system. Below 3 MeV the He3(He3, 2p)He4 reaction mechanism is observed to be changing and further measurements are suggested in view of the importance of this reaction in stellar interiors.