Energy Release fromBe9(d,α)Li7and the Production ofLi7

Abstract

The $\ensuremath{\alpha}$-particles from ${\mathrm{Be}}^{9}(d,\ensuremath{\alpha}){\mathrm{Li}}^{7}$ have been investigated with a variable air pressure absorption cell, ionization chamber and linear amplifier. It has been established that there are two groups of $\ensuremath{\alpha}$-particles differing at 760 mm pressure and 15\ifmmode^\circ\else\textdegree\fi{}C by 3.08\ifmmode\pm\else\textpm\fi{}0.10 mm range reduced to zero bombarding voltage. The groups have been shown to be associated with the production of ${\mathrm{Li}}^{7}$ in the ground state and in an excited state. At 239 kv bombarding voltage, the excited state is formed 1.7 times as often as the ground state. The energy balance, $Q$, associated with the production of the ground state has been determined to be 7.093\ifmmode\pm\else\textpm\fi{}0.022 Mev. The energy of the excited level has been determined to be 494\ifmmode\pm\else\textpm\fi{}16 kev. The total yield curve for $\ensuremath{\alpha}$-particles has been investigated from 235 kv to 390 kv bombarding voltage. The measured value for the energy of the excited level in ${\mathrm{Li}}^{7}$ is discussed in connection with values from other reactions in which ${\mathrm{Li}}^{7}$ is an end product and with $\ensuremath{\gamma}$-ray measurements of the level.