Gamma Spectrum of Ho^160m Isomer

During the decay of Er¹⁶⁰ (T_1⁄2=28.7 hours), the isomeric state Ho^160m (T_1⁄2=5.1 hours) with an energy of 60 keV is excited. The decay of this level occurs both by electronic capture and by isomeric E3 γ-transition to the ground state. Beta decay of Ho¹⁶⁰ occurs with a half-life of 25.6 minutes. It has already been established that there is a genetic connection between Ho¹⁶⁰ levels. Gamma radiation occurs after the β-decay of both states of Ho¹⁶⁰ and is caused by transitions between the levels of the even-even deformed nucleus Dy¹⁶⁰. The goal of this work was to establish which γ-rays arise directly from the β-decay of the isomeric level Ho^160m. When studying the γ-spectrum of Er¹⁶⁰, purified from daughter holmium, one can observe an increase in the intensity of γ-lines following the β-decay of both Ho^160m and Ho¹⁶⁰, and the nature of their increase is different. This difference in rise rate is used in our work. The chromatographic method of erbium purification allowed us to begin measuring the γ-spectrum 2 minutes after the erbium fraction left the column. The source was the erbium fraction of the products of irradiation of tantalum with protons with an energy of 660 MeV at the JINR synchrocyclotron. Secondary separation was carried out 2 days after irradiation, when almost pure Er¹⁶⁰ and the daughter isotope Ho¹⁶⁰ remained in the erbium fraction