The nuclide ${\mathrm{Br}}^{86}$ has been identified by chemical separation following neutron bombardment of enriched ${\mathrm{Kr}}^{86}$. A half-life of 54±2 sec was observed. $\beta$- and $\gamma$-scintillation counting with multichannel pulse-height analysis indicate a complex beta spectrum with an end point of 7.1±0.5 MeV for the most energetic component and prominent $\gamma$ rays at 1.57 and 2.76 MeV. The effect of ${\mathrm{Br}}^{86}$ on the interpretation of previous data on short-lived bromine fission products is discussed. Rough values for the relative ($n, p$), ($n, \mathrm{pn}$), and ($n, \alpha$) reactions on ${\mathrm{Kr}}^{86}$ were determined as 1: 1: 0.05, respectively. The ratio of ${\mathrm{Se}}^{83}$ isomers formed by the ($n, \alpha$) reaction is 3: 1 in favor of the metastable state.

• Received 12 January 1962

DOI:https://doi.org/10.1103/PhysRev.127.563