The fraction of ${\mathrm{Be}}^7$ $K$ capture to the 478 kev excited state of ${\mathrm{Li}}^7$ has been experimentally determined to be 0.107±0.02. The experimental method consisted in measuring the number of ${\mathrm{Be}}^7$ atoms by counting neutrons from the ${\mathrm{Li}}^7\mathrm{}\left(\mathrm{pn}\right)\mathrm{}{\mathrm{Be}}^7$ reaction, and in observing the subsequent number of 478 kev gammas by use of a counter calibrated by beta-gamma-coincidences from ${\mathrm{Au}}^{198}$. Implications concerning the character of the 478 kev ${\mathrm{Li}}^7$ level are discussed.

• Received 23 May 1949

DOI:https://doi.org/10.1103/PhysRev.76.614