Nuclear Data Sheets for A = 89
The evaluated experimental data are presented for 14 known nuclides of mass 89 (Ge, As, Se, Br, Kr, Rb, Sr, Y, Zr, Nb, Mo, Tc, Ru, Rh). New data on high–spin excitations are available for 89 Kr, 89 Rb, 89 Sr, 89 Tc and 89 Ru, including a superdeformed structure in 89 Tc. Fluorescence studies in 89 Y have revealed a large number of new levels in 7–11 MeV range. New two–neutron transfer data are available for 89 Zr. New direct and precise measurement of atomic masses of 89 Se, 89 Br, 89 K r, 89 Rb, 89 Mo and 89 Tc have greatly improved the Q value landscape in this mass region. This work supersedes previous A=89 evaluation published in 1998Si31, and also the older ones 1989Si20, 1975Ko21, and M.W. Johns et al., Nuclear Data Tables A 8, 373 (1970). In spite of extensive experimental work on the isobaric nuclei of this mass chain several deficiencies remain. The identification of 89 Rh isotope remains unconfirmed. The half–lives of ground states of 89 Ge, 89 As and 89 Rh have not been measured, only the lower limits are estimated from time–of–flight in a reaction and experimental arrangement, where produced and identified. The decay schemes of 89 Ge, 89 As, 89 Se, 89 Ru and 89 Rh are not known, and those for 89 Tc and 89 Mo are incomplete. High–lying (neutron unbound) levels in 89 Kr, expected to be populated in the decay of 89 Br, have not been investigated. The spins and parities for levels in 89 Kr are largely unassigned, while for 89 Tc and 89 Ru, only few low–spin excitations are established. For 89 Rb, little information is available for high–spin structures. Detailed gamma–ray data are available for 88 Sr(n, γ ) 89 Sr reaction, but most of these γ rays remain unassigned in a level scheme. Excited state data are nonexistent for 89 Ge, 89 As, 89 Se, 89 Br and 89 Rh. The 89 Y and 89 Zr are the most extensively studied nuclei in A=89.