Nuclear levels of ¹⁹⁹Au

Abstract

The low energy level scheme of ¹⁹⁹Au as observed in the decay of 30 min acitivity of ¹⁹⁹Pt has been studied using an intermediate image beta ray spectrometer and scintillation coincidence spectrometers in conjunction with a 512-channel analyser. Four beta groups of end-point energies at 1690±50, 1370, 1150 and 900 keV have been identified. The gamma-rays of energies 75, 197, 245, 320, 475, 540, 715, 790 and 960 keV were observed in the scintillation spectrum. To explain the various β-γ, γ-β and γ-γ coincidences and their relative intensities, levels at 75, 320, 475, 540, 737, 790 and 960 keV have been proposed. This new level scheme of ¹⁹⁹Au shows a close similarity with those of neighbouring odd-mass gold nuclei. An isomeric state at about 475 keV has been identified, also suggesting a possible existence of the h_11/2 state in the ¹⁹⁹Au nucleus.