抄録
Internal conversion lines in decay of 200Tl have been measured with a large air-core spectrometer. The spin assignment for the third excited 1029-keV level of 200Hg is discussed mainly based on the multipolarity of the 661-keV transition from this level to the first 2+ level. It was found to be of almost pure E2 character from the experimental L-subshell line ratios. The spin and parity of the level are concluded to be most likely 0+. The internal conversion measurement of the 1029-keV line with high resolution showed the presence of a doublet of 1027.13-keV and 1029.21-keV lines. The monopole strength parameter of the 1029-keV E0 transition is estimated to be 0.53×10−2≥ρ.
