Metastable State ofGe73

Abstract

A new short-period isomeric activity with a gamma-ray energy of 54 kev and a half-life of 0.53±0.03 sec has been observed following thermal neutron absorption in ${\mathrm{Ge}}^{72}$. The gamma-ray transition is shown to arise from a metastable state of ${\mathrm{Ge}}^{73}$ at 67.4-kev excitation energy, known from the decay of ${\mathrm{As}}^{73}$, but not previously characterized as to half-life. Chemical separation of ${\mathrm{Ge}}^{73m}$ from ${\mathrm{As}}^{73}$ by a gas-sweeping technique was sufficiently rapid to allow decay measurements of the separated gas. The half-life so determined is within experimental error the same as that found in the neutron-produced activity.