FORMATION OF He$sup 6$ BY 14-MEV NEUTRON BOMBARDMENT OF Li AND Be

Formation of ${\mathrm{He}}^{6}$ by bombardment of ${\mathrm{Li}}^{6}$, ${\mathrm{Li}}^{7}$, and ${\mathrm{Be}}^{9}$ with 14-Mev neutrons has been observed. The ${\mathrm{He}}^{6}$ was identified by its known half-life and the decay rate observed on a ten-channel time-delay analyzer. Beta-rays from the ${\mathrm{He}}^{6}$ were detected by means of a thin-walled proportional counter, and the over-all counting efficiency was determined by using the ${\mathrm{Cu}}^{63}(n, 2n){\mathrm{Cu}}^{62}$ reaction. Cross sections determined for the ${\mathrm{Li}}^{6}(n, p)$, ${\mathrm{Li}}^{7}(n, d)$, and ${\mathrm{Be}}^{9}(n, \ensuremath{\alpha})$ reactions were 6.7\ifmmode\pm\else\textpm\fi{}0.8, 9.8\ifmmode\pm\else\textpm\fi{}1.1, and 10\ifmmode\pm\else\textpm\fi{}1 millibarns, respectively. The half-life of ${\mathrm{He}}^{6}$ was found to be 0.83\ifmmode\pm\else\textpm\fi{}0.03 second.