The reaction ${\mathrm{Li}}^7(d, \alpha ){\mathrm{He}}^5$ was studied with the use of coincidence circuitry and solid-state charged-particle detectors. Targets of natural and isotopic lithium were bombarded with 150-200 keV deuterons, and $\alpha$ particles emitted at laboratory angles of 90 and 82 deg were detected in coincidence. The ($d, \alpha$) reaction proceeding to the ground state of ${\mathrm{He}}^5$ was observed, its differential cross section at 90 deg was measured relative to that for ${\mathrm{Li}}^6(d, \alpha )\alpha$, and a value of ${2.4}_{-1.0\mathrm{}}^{+1.5\mathrm{}}$ was assigned to the parameter $A$ in the function $f\left(\theta \right)=1+A{sin}^2\theta$ which describes the center-of-mass $\alpha$-particle distribution resulting from the disintegration of ${\mathrm{He}}^5$. The first excited state of ${\mathrm{He}}^5$ was found to have an excitation energy of 2.6±0.4 MeV and a width of 4.0±1.0 MeV. The intensity of the excited state alpha group was greater than that of the ground-state group by a factor of about 1.5. There was no evidence for any other excited state up to at least 7 MeV. The ratio of the differential cross sections at 90 deg for ${\mathrm{Li}}^6(d, p){\mathrm{Li}}^7$ and ${\mathrm{Li}}^6(d, \alpha )\alpha$ was determined for several values of $E_d$ and found to agree with reported cross-section data.

• Received 16 July 1963

DOI:https://doi.org/10.1103/PhysRev.133.B71