D.C. Kocher

Nuclear Data Sheets for A = 90*

Abstract The 1961 version of Nuclear Data Sheets for A=90 and the 1970 Midstream Evaluation, A=90 +J. B. Ball, M. W. Johns, and K. Way, Nuclear Data Tables 8, 407 (1970)+, have been revised on the basis of experimental data received prior to May 1, 1975. Results from approximately 225 papers and communications chosen from the extensive literature for this A-chain have been included in the present evaluation. Numerous additional references dealing with reaction mechanism studies and nuclear structure theory are not included in this compilation, but are available upon request from the Nuclear Data Project. Data on nine A=90 nuclei are presented. The decay of 90 Br has been observed, but the decay scheme has not been established. Recent unpublished results on 90 Kr and 90 Rb decays are presented. These results are not yet comlete, but appear to be considerably more extensive than previously published work. The particularly simple decay schemes for 90 Sr and 90 Y are wellk known. A few spin assignments have been proposed for levels in 90 Sr, but additional reaction studies would be useful. Many spin assignments have been made for levels in 90 Y, 90 Zr, 90 Nb, and 90 Mo from a variety of decay and reaction studies. The results for 90 Zr are particularly extensive. The decay schemes for 90 Nb and 90 Mo appear reasonably well established. Recent results on the decay of two 90 Tc isomers are presented, but the decay schemes have not been established and the energy ordering of the two isomers is not known.

Nuclear data sheets for A = 89

Abstract The 1961 version of Nuclear Data Sheets for A = 89 and the 1970 Midstream Evaluation, A = 89 [M. W. Johns, J. Y. Park, S. M. Shafroth, D. M. Van Patter, and K. Way, Nuclear Data Tables 8, 373 (1970)], have been revised on the basis of experimental data received prior to August 1, 1975. Results from approximately 150 papers and communications chosen from the extensive literature for this A-chain have been included in the present evaluation. Numerous additional references dealing wtih reaction mechanism studies and nuclear structure theory are not included in this compilation, but are available upon request from the Nuclear Data Project. Data on nine A = 89 nuclei are presented. Only the half-lives for 89Se and 89Br have been determined. The decay schemes for 89Kr and 89Rb appear to be well established. The decay scheme for 89Sr is particularly simple, but the intensity for the single γ-ray in the decay is not well known. Many spin assignments have been made for levels in 89Sr, 89Y, and 89Zr from a variety of decay and reaction studies. The decay schemes for low-spin and high-spin isomers in both 89Zr and 89Nb appear to be well established, but the energy ordering of the two isomers in 89Nb is not known. On the basis of recent results, it appears that the previously claimed isotope 89Mo has not yet been observed.

Nuclear data sheets for A = 58*

Nuclear structure data available through June 1976 are compiled, and adopted level properties are given. The bulk of the data is presented pictorially for easy comparison. Experimental details, references, and additional comments, where required, are given in the text. All drawings, tables, and comments are reproduced from the computerized Evaluated Nuclear Structure Data File (ENSDF). Any additions or corrections desired by the users should be addressed to the compilers for maintenance and updating of the computer file.

Nuclear data sheets for A = 92

Abstract The 1960 version of the Nuclear Data Sheets for A = 92 has been revised on the basis of experimental data received prior to March 1, 1972. Information from approximately 150 papers and communications has been included in the present evaluation. Ten nuclei are known for A = 92. Only the presumed ground states and their half-lives have been established for 92Br, 92Kr, and 92Ru. Extensive investigations of the 92Kr, 92Rb, and 92Sr decay schemes have been reported, but few spin-parity assignments can be made for levels in the daughter nuclei. The stable nuclei 92Zr and 92Mo have been studied via β-decay, γ-decay, transfer reactions, and inelastic scattering; an appreciable number of spin assignments for low-lying levels are firm. Levels in 92Nb up to 0.5 MeV in excitation are well established by transfer reaction and γ-decay studies; however, only tentative spin assignments can be made, many of which are based on shell-model arguments. An analysis of a preliminary 92Tc decay scheme has resulted in a tentative Jπ=(7+) assignment for the 92Tc ground state, a value not previously suggested in the literature. Reaction, γ-decay, and 92Ru decay studies have established some excited levels in 92Tc, but no spins are known. Several important gaps and uncertainties remain in the data. The normalizations for transition intensities in the 92Kr and 92Rb decay schemes determined by an indirect method result in unexpectedly low log ft values for the ground-state β-branches. Reaction studies are needed to resolve the ambiguity in the placement of low-lying levels in 92Y from 92Sr decay. Above 2.4 MeV in excitation in 92Zr, the correspondence between levels observed in 92Y decay, transfer reactions, and inelastic scattering is not well determined, resulting primarily from the lack of precise energy determinations in reaction studies. An accurate determination of the half-life of the 92Nb ground state and a careful search for the γ-decay of the first-excited state might establish the spin of the ground state independently of shell-model arguments. Firm spin assignments for the lowest-lying 6+ and 8+ levels in 92Mo and a confirmation of the proposed 92Tc decay scheme are required for a firm spin assignment for the 92Tc ground state. The placement of levels in 92Tc observed in γ- and β-decay is uncertain.

Nuclear data sheets for A = 55

Abstract The 1970 version of Nuclear Data Sheets for A = 55 has been revised on the basis of experimental data received prior to March 1, 1976. Results from approximately 220 papers and communications have been included in the present evaluation. Data on five A = 55 nuclei are presented. The decay schemes for 55 Cr, 55 Fe, and 55 Co are well established. Many excited levels are known in 55 Cr, 55 Mn, 55 Fe, and 55 Co from a variety of decay and reaction experiments. Many firm or tentative spin assignments are made, and many half-lives for excited levels in 55 Mn, 55 Fe, and 55 Co have been measured. An uncertainty in the level scheme for 55 Mn occurs near 1290 keV, where the number of distinct levels and their spins cannot be unambiguously determined. The nucleus 55 Ni has been observed for the first time in the ( 3 He, 6 He) reaction, but the decay of 55 Ni has not yet been observed.

Nuclear data sheets for A = 93

Abstract The 1960 version of the Nuclear Data Sheets for A = 93 has been revised on the basis of experimental data received prior to November 1, 1972. Information from approximately 180 papers and communications has been included in the present evaluation. Nine nuclei are known for A = 93. Only the presumed ground states and their half-lives have been established for 93Kr, 93Rb, and 93Sr, and only fragmentary information on their decay schemes is available. The Q-Value for 93Sr decay is not well determined experimentally. Decay studies and pick-up reactions have established a few low-lying levels in 93Y. Many spin assignments have been made for levels in 93Zr on the basis of decay studies, transfer reactions, and measurements on isobaric analog resonances in 93Nb. The decay schemes of long-lived 93Zr and 93Mo are still somewhat uncertain, since the existence of a decay on the 93Nb ground state is not well established for either nucleus. Furthermore, the half-life of 93Mo has not been directly measured. Low-lying levels in stable 93Nb have been extensively studied via β-decay, Coulomb excitation, neutron inelastic scattering and transfer reactions, and an appreciable number of spin assignments are firm. Extensive β-decay, γ-decay, transfer and charge-exchange reaction, and isobaric analog resonance measurements have led to many spin assignments for levels in 93Mo. The nucleus 93Tc has been studied via γ-decay and transfer reactions, but few spin assignments are firm. Recent measurements indicate the existence of two levels in 93Ru with approximately the same half-life, but the ordering of the levels and their decay properties is not well established. The well-established MA γ-decays of the first-excited states of 93Nb and 93Tc are found to have large enhancements of 13.2 and 26.7, respectively, the latter being the largest M4 enhancement known. The electron-capture decay of the first-excited state of 91Tc also is found to have an unusually low log ft of 4.2.

Nuclear data sheets for A = 94

Abstract The 1960 version of the Nuclear DAta Sheets for A = 94 has bee revised on the basis of experimental data received prior to April 1, 1973. Information from approximately 165 papers and communications has been included in the present evaluation. Nine nuclei are well established for A = 94. Only the presumed ground states and their half-lives are known for 94Kr and 94Rb. The 94Sr decay scheme has recently been determined. Some discrepancies are found in the reported decay schemes for 94Y. Many spin assignments for low-lying levels in the stable nuclei 94Zr and 94Mo are firm. Many levels are known in 94Nb, but only a few spin assignments can be made independently of shell-model predictions. The decay schemes for the two 94Tc isomers appear well established. A few firm spin assignments are made for levels in 94Te and 94Ru. The two known branches in 94Ru decay are found to have unusully low log ft values ( The existence of the nucleus 94Rh has been reported for the first time, but details of the observations are not yet published.

Nuclear Data Sheets for A = 103

Abstract The 1961 version of the Nuclear Data Sheets for A = 103 has been revised on the basis of experimental data received prior to March 1, 1974. Information from approximately 150 papers and communications has been included in the present evaluation. Data on nine A = 103 nuclei are presented. The compilers regard the assignment of fission-fragment γ-rays to 103Zr and 103Nb as uncertain, and no measurements on the decay of these nuclei have been made. The half-lives of 103Mo and 103Cd are known, but no decay schemes have been proposed. The compilers propose a decay scheme for 103Tc based mainly on unpublished measurements, but further work is needed to determine absolute transition intensities and the decay energy. The decay schemes for 103Ru, 103Pd, and 103Ag appear to be well established on the basis of extensive but mainly unpublished results. The spins of a few low-lying levels in 103Ru are determined by single-nucleon transfer reactions. Spin assignments have been made for most low-lying levels in the stable nucleus 103Rh from 103Ru decay, 103Pd decay, and Coulomb excitation. The spins of many levels in 103Pd have been determined from extensive unpublished results in 103Ag decay, single-nucleon transfer reactions, and in-beam γ-ray studies. Only one excited level is known in 103Ag. For papers concerned with nuclear structure theory for A = 103 nuclei, see 66Sh18, 72Ku25, 73Bo16, and 73Im01.

Nuclear data sheets for A = 79

Abstract The 1966 version of Nuclear Data Sheets for A = 79 has been revised on the basis of experimental data received prior to December 1, 1974. Information from approximately 85 papers and communications has been included in the present evaluation. Data on eight A = 79 nuclei are presented. The half-life and decay energy for 79 Ga have been proposed, but the compilers do not regard the nuclidic assignment as firmly established. The existence of two isomers in 79 Ge has recently been proposed. The compilers tentatively assign a 42-s activity to the 79 Ge ground state, and a partial decay scheme is given. The compilers do not regard the assignment of a 19.1-s activity to 79 Ge as firmly established. The spin of the 79 As ground state is known from its decay to levels in 79 Se. Many levels from 79 Se are known from 79 As decay, single-nucleon transfer, and a level scheme for 78 Se(th n, γ ) proposed by the compilers. Only an upper limit for the half-life of long-lived 79 Se has been determined; this nucleus decays directly to the 79 Br ground state. Levels in stable 79 Br up to 2 MeV are known from 79 Kr decay, Coulomb excitation and resonance fluorescence, and (n,n′ γ ). Most of the information on excited levels in 79 Kr is regarded by the compilers as tentative, since the 79 Rb decay scheme is not well established and all reaction studies are unpublished. Only the ground state of 79 Rb is known, and its spin cannot be determined since the intensity of the decay to the 79 Kr ground state is not accurately known. The compilers tentatively assign as 8.1-m activity to the 79 Sr ground state, but no decay scheme has been proposed. The compilers regard the assignment of a 4.4-m activity to 79 Sr as not firmly established. The only data on excited levels of 79 Sr are unpublished.

Nuclear data sheets for A = 120

Abstract The 1960 version of Nuclear Data Sheets for A = 120 has been revised on the basis of experimental data received prior to September 1, 1975. Results from approximately 130 papers and communications have been included in the present evaluation. Data on ten A = 120 nuclei are presented. Two β —decaying isomers are known for each of the odd-odd nuclei 120 Ag, 120 In, 120 Sb, and 120 I. Only for 120 Ag is the energy ordering of the two isomers known, and only for 120 In and 120 Sb are the decay schemes for the two isomers well determined. With the exception of 120 I, other excited levels in these odd-odd nuclei have not been identified. Reaction studies to determine excited levels in 120 Sb would seem particularly appropriate. Other than a half—life, little is known about the remaining odd-odd nucleus, 120 Cd. For the even-even nuclei, the decay scheme for 120 Cd is somewhat uncertain, although it is likely that most of the decay directly feeds the 1 + isomer in 120 In. Many levels in stable 120 Sn and 120 Te are known from a variety of decay and reaction studies. The complex decay scheme for 120 Xe appears well determined, but little is known about 120 Ba decay. A few excited levels for 120 Xe and 120 Ba comprising rotational bands have been proposed from in—beam γ -ray spectroscopy.