${}_{}{}^3{}_{}{}^{}\mathrm{He}$ spectra from the bombardment of tritium and of ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ targets with 22.25-MeV tritons are presented. No clear evidence for new states in either residual nucleus is obtained; however, the ${}_{}{}^3{}_{}{}^{}\mathrm{H}(t, {}_{}{}^3{}_{}{}^{}\mathrm{He})3n$ spectra provide weak evidence for the existence of a "trineutron" unbound by 1 to 1.5 MeV.

• Received 24 July 1968

DOI:https://doi.org/10.1103/PhysRev.176.1163