Gamma-Ray Excitation ofTa181Isomer

Abstract

The 615-kev isomeric state in ${\mathrm{Ta}}^{181}$ was excited by 6-Mev bremsstrahlung gamma rays. The half-life and gamma ray spectra were measured with a NaI(Tl) scintillation detector. The measured half-life is 18.1±0.3 μsec. The relative intensities of the 134-kev, 346-kev, and 482-kev gamma rays and the 56-kev x-ray from internal conversion are 57, 16, 100, and 32 and agree with the results obtained from the excitation of this state by beta decay of ${\mathrm{Hf}}^{181}$. An estimate of the yield is given.