The energy spectra of tritons, $\alpha$ particles, and deuterons from the reactions ${}_{}{}^3{}_{}{}^{}\mathrm{He}\mathrm{}(d,t)2p$, $d({}_{}{}^3{}_{}{}^{}\mathrm{He},t)2\mathrm{}p$, ${}_{}{}^3{}_{}{}^{}\mathrm{He}({}_{}{}^3{}_{}{}^{}\mathrm{He},{}_{}{}^4{}_{}{}^{}\mathrm{He})2\mathrm{}p$, and $p({}_{}{}^3{}_{}{}^{}\mathrm{He},d)2\mathrm{}p$ were measured at forward angles 0° to 5°, using 36-MeV deuterons and 53-MeV ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ from the Oak Ridge isochronous cyclotron. The reaction $d({}_{}{}^3{}_{}{}^{}\mathrm{He},t)2\mathrm{}p$ at 0° was also studied at 74 MeV. All spectra had peaks in the high-energy region which are attributed to the enhancement of the cross section due to the final-state interaction of the two protons. The final-state interaction theory of Watson and Migdat gives an adequate representation of the data for the reactions ${}_{}{}^3{}_{}{}^{}\mathrm{He}\mathrm{}(d,t)2p$ and ${}_{}{}^3{}_{}{}^{}\mathrm{He}({}_{}{}^3{}_{}{}^{}\mathrm{He},{}_{}{}^4{}_{}{}^{}\mathrm{He})2\mathrm{}p$ for the known proton-proton interaction. For the other two reactions, $d({}_{}{}^3{}_{}{}^{}\mathrm{He},t)2\mathrm{}p$ and $p({}_{}{}^3{}_{}{}^{}\mathrm{He},d)2\mathrm{}p$, the observed peaks are much narrower than the predictions of the Watson-Migdal theory. In the case of $d({}_{}{}^3{}_{}{}^{}\mathrm{He},t)2\mathrm{}p$ the narrower peak could be explained by assuming the primary reaction mechanism to be a charge-exchange process. A search for a three-proton enhancement in the reaction ${}_{}{}^3{}_{}{}^{}\mathrm{He}({}_{}{}^3{}_{}{}^{}\mathrm{He},t)3\mathrm{}p$ was unsuccessful.

• Received 27 December 1967

DOI:https://doi.org/10.1103/PhysRev.169.825