The Midstream Evaluation, A = 88 [Nuclear Data Tables A8, 345–371 (1970)] has been revised on the basis of experimental data received before September 1, 1975. Data for the nine known members of the A = 88 isobar are presented.
Very little is known about 88Se and the available data are inconsistent. The γ-ray spectrum following the 88Br decay has been measured. The resulting level scheme for 88Kr is shown in Drawing 2. The dashed levels result from energy sums involving only two γ-rays and no coincidence data. These data and the 86Kr(t,p) data indicate that the levels at 1644.1 keV (β−) and 1654 keV (t,p) are not equivalent. More decay and reaction data are required before the 88Kr level properties can be considered firm. The γ-rays following the 88Kr β-decay are well established. The agreement of the resulting 88Rb level scheme with that obtained from the 87Rb(d,p) reactions is quite good. The 88Rb β-decay has been well established through many extensive measurements using several different source preparations. The levels of 88Sr have been investigated through many reactions (more than 20 given here) and the 88Rb β- and 88Y ε-decays. Adopted levels through 4.85 MeV are given on the Data Sheets. Above 4.85 MeV inconsistencies in the various energy calibrations obscure the assignment of corresponding levels. A detailed discussion of the various 88Sr(n,γ) experiments can be found in 69Ly07. The 88Y ε-decay is presented as an adopted scheme derived from data discussed in ten publications. The levels of 88Y are well established through many reactions including several (charged particle, nγ) which provide some very accurate level energies. The simple 88Zr ε-decay is shown on Drawing 1. The adopted level properties are from the 90Zr(p,t)88Zr reactions. These data correspond well through 3 MeV. The 88Nb ground-state and isomeric ε-decays need further work. The 14.3-m decay data presented here are in poor agreement with a recent measurement by 74Ba55 which identifies an additional 26 γ-rays, 18 of which are not placed in the decay scheme. The tentative assignment of Jπ(88gNb)=(8+) and Jπ(88mNb)=(4−) are based on weak arguments and should be reconsidered in the light of new decay data. The relative position of these levels is unknown. Very little data are available for 88Mo.
In a few cases unpublished data have been frequently cited by other researchers. These unpublished data have been included for reference and are clearly marked as such. The Adopted Properties were not influenced by these data.