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Level energies of low-spin yrast states up to spin 8 § are firmly established on the basis of e-7-spectroscopy. Six new a-lines associated with the decay from 212p0 suggest additional levels populated in the 3-decay of 2~2Bi.

Delayed-neutron emission probabilities (P") were measured for 16 isotopes of Br, Rb, I, and Cs. Sources of chemically and mass separated nuclides were obtained from an on-line mass spectrometer facility. Neutrons were counted in a multitube polyethylene-moderated detector. The total number of precursor atoms was determined by direct counting of ions deposited on the first dynode of an electron multiplier. The P"values from this work generally agree with earlier measurements for the longer-lived precursors but are consistently higher for the shorter-lived precursors. A log-log plot of P"versus the reduced energy window (Q& -B")l(Q& -C) gives a straight line with a slope of 6.0~1.4 in agreement with simplified theoretical predictions. Half-lives of Rb and Cs nuclides measured by neutron decay curves are given. P", T&~2, on-line mass separation, polyethylene-moderated neutron counter.

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