LOW ENERGY LEVELS OF 211BI

The gamma-ray spectrum of the excited levels of 211Bi populated following the β-decay of 211Pb was examined using both NaI(Tl) and germanium detectors. Coincidence, component sum coincidence and sum coincidence techniques were used to evaluate the spectra and the possible cascades which occur. Evidence is presented for several new transitions and the results of previous work are largely confirmed with respect to the decay scheme. There are however some disagreements with previous measurements of the γ-decay relative intensities. In particular the 405:427 keV intensity is 1:0.40±0.03 and together with the relative intensities of K-shell conversion electrons implies that the 427 keV transition is essentially pure M1. The conversion coefficients for other dominant transitions are evaluated. © 1968.