Zur Isomerie des Au¹⁹⁷

Abstract

Au^197m was produced from Au by fast neutron irradiation and investigated using scintillation and semiconductor gamma spectrometers. The following results were obtained: Half-lifeT _1/2=(7,5± 0,2) sec; conversion coefficients of the 130,5 keV isomeric transition:α _K130.5=0,9±0,3 andα _tot130,5=28 ± 4, indicating anE3 multipolarity. Conversion coefficients of the subsequent 278,5 keV transition:α _K278,5=0,32±0,04 andα _tot278,5=0,44±0,10. This transition was identified asM1 with anE2 admixture of (13± 13)%. The 278,5 keV level decays either by this transition (98,5%) or by a 202 keV- 77 keV cascade (1,5%). The experimental gamma transition probabilities are in reasonable agreement with the theoretical values calculated from the model ofKisslinger andSorensen.