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

Abstract

The $\alpha$-particles from ${\mathrm{Be}}^9(d,\alpha ){\mathrm{Li}}^7$ 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 $\alpha$-particles differing at 760 mm pressure and 15°C by 3.08±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±0.022 Mev. The energy of the excited level has been determined to be 494±16 kev. The total yield curve for $\alpha$-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 $\gamma$-ray measurements of the level.