A new neutron-deficient isotope of krypton, ${\mathrm{Kr}}^{76}$, with a half-life of 9.7±0.5 hours has been produced by the spallation of yttrium. Its genetic relationship with its 17.2-hour ${\mathrm{Br}}^{76}$ daughter was established by isolation experiments. ${\mathrm{Kr}}^{76}$ decays by weak positron emission (probably >0.6 Mev). A search for electron capture by this nuclide gave negative results.

• Received 21 September 1953

DOI:https://doi.org/10.1103/PhysRev.93.175