A Study of the Breakup of Li8

作者：T. W. Bonner, J. E. Evans, C. W. Malich, J. R. Risser · 发表于：Physical Review · 年份：1948 · DOI：10.1103/physrev.73.885 · 被引用次数：28 · 研究领域：Atomic and Molecular Physics、Nuclear physics research studies、Radioactive Decay and Measurement Techniques

An experimental technique in which radioactive ${\mathrm{Li}}^{8}$ atoms are introduced into the gas of a cloud chamber has been used to determine the energy distribution of the alpha-particles from the ${\mathrm{Li}}^{8}$ breakup. The maximum of the distribution occurs at 3.3 Mev and the width of half-intensity is 1.2\ifmmode\pm\else\textpm\fi{}0.2 Mev. The theoretical distribution ${N}_{\ensuremath{\alpha}}d{E}_{\ensuremath{\alpha}}=[{P}_{\ensuremath{\alpha}J}\frac{{(Q\ensuremath{-}2{E}_{\ensuremath{\alpha}})}^{5}}{{({E}_{0}\ensuremath{-}2{E}_{\ensuremath{\alpha}})}^{2}}+\frac{1}{4}{\ensuremath{\Gamma}}^{2}]d{E}_{\ensuremath{\alpha}}$with ${E}_{0}=3.1$ Mev, $\ensuremath{\Gamma}=0.8$ Mev, and $J=4$, gives good agreement with experimental data. ${N}_{\ensuremath{\alpha}}$ is the relative number of alpha-particle pairs, ${E}_{\ensuremath{\alpha}}$ is the energy of one alpha-particle, ${P}_{\ensuremath{\alpha}J}$ is the penetrability of one alpha-particle from a ${\mathrm{Be}}^{8}$ nucleus having $J$ units of total angular momentum, and ${E}_{0}$ and $\ensuremath{\Gamma}$ are, respectively, the mean energy and width at half-intensity of the excited level in ${\mathrm{Be}}^{8}$. No evidence was found for a short-range group of alpha-particles which would correspond to the disintegration energy of the ground state of ${\mathrm{Be}}^{8}$.