${\mathrm{H}}^3(\alpha , \gamma ){\mathrm{Li}}^7$ and ${\mathrm{He}}^3(\alpha , \gamma ){\mathrm{Be}}^7$ Reactions

The cross sections for the ${\mathrm{H}}^3(\alpha , \gamma ){\mathrm{Li}}^7$ and ${\mathrm{He}}^3(\alpha , \gamma ){\mathrm{Be}}^7$ reactions have been measured at bombarding energies of 480, 720, 940, 1130, and 1320 kev. The cross sections at the lower bombarding energies may be fitted within the experimental uncertainties by the expressions $\sigma =0.12(1-0.00051\mathrm{}{E}_{\alpha }){E_{\alpha }}^{-1\mathrm{}}\exp (-125\mathrm{}{E_{\alpha }}^{-\frac{1}{2}})$ b for the ${\mathrm{H}}^3$ reaction and $\sigma =2.8(1-0.00055\mathrm{}{E}_{\alpha }){E_{\alpha }}^{-1\mathrm{}}\exp (-250\mathrm{}{E_{\alpha }}^{-\frac{1}{2}})$ b for the ${\mathrm{H}}^3$ reaction, with $E_{\alpha }$ in kev.