Singlet Deuterons (d) from (p, d) Reactions

Abstract

Singlet deuterons $d$ (i.e., a neutron-proton system in the $S=0$, $T=1$ virtual state) are treated as particles emitted from nuclear reactions. A method for detecting them by $n\ensuremath{-}p$ coincidence time-of-flight techniques is described. ($p, d$) reactions induced by 12-MeV protons on ${\mathrm{Li}}^{7}$ and ${\mathrm{Be}}^{9}$, and by 17-MeV protons on ${\mathrm{Be}}^{9}$, ${\mathrm{C}}^{13}$, ${\mathrm{Mg}}^{25}$, and ${\mathrm{Sn}}^{117}$ are investigated. In the lighter elements, angular distributions of $d$ are measured and compared with those of deuterons from analogous ($p, d$) reactions, and the ratios $R=\frac{\ensuremath{\sigma}(p, d)}{\ensuremath{\sigma}(p, d)}$ are determined. Semiquantitative comparisons with theory indicate reasonable agreement. In ${\mathrm{Mg}}^{25}$ and ${\mathrm{Sn}}^{117}$, no ($p, d$) reactions could be detected, although they are expected to be observable at least in ${\mathrm{Sn}}^{117}$.