Neutrons from Deuteron Breakup on D, T, andHe4

Abstract

The continuous neutron spectra produced by deuteron bombardment of D, T, and ${\mathrm{He}}^4$ have been studied at deuteron energies near 9 MeV with a time-of-flight spectrometer. Angular distributions of the continuous spectra from D+$d$ and ${\mathrm{He}}^4$+$d$ were obtained for deuteron energies of 9 and 10 MeV. The center-of-mass angular distributions are peaked forward for neutrons of all energies. Two maxima present in the 0° spectrum from ${\mathrm{He}}^4$+$d$ at $E_d=10\mathrm{}$ MeV are consistent with the interpretation that ${\mathrm{He}}^5$ and ${\mathrm{Li}}^5$ are produced in their ground states as alternative intermediate steps in the reaction. Two maxima are also present in the continuous neutron spectrum from T+$d$. The higher energy maximum occurs near the maximum possible neutron energy from the $\mathrm{T}(d, np)\mathrm{T}$ reaction and cannot be caused by the $\mathrm{T}(d, 2n){\mathrm{He}}^3$ reaction. If this peak is caused by an excited state in ${\mathrm{He}}^4$, it would correspond to an excitation in ${\mathrm{He}}^4$ of 20.0±0.2 MeV, and be unbound.