Multipolarities of γ-rays from 92, 94Nb and 94,95,96,97,98Tc
Abstract
92, 94Nb and 94, 96, 98Tc have been produced by the (p, n) reaction at proton energies on and near the isobaric analog resonance. 95,97Tc have been produced by the (p, γ) reaction below the (p, n) threshold. Internal conversion electrons due to the decay of their excited states were detected on-line with a mini-orange spectrometer which is optimized for the energy range 50 to 500 keV. Gamma rays from these nuclei were detected with a thin Ge(Li) detector. Isomeric-delayed internal conversion electrons and γ-rays were observed, using a nanosecond-pulsed beam. The internal conversion coefficients for 55 transitions in these nuclei have been determined and their multipolarities deduced. The multipolarity of the transitions in these nuclei is predominantly M1. Negative parities have been assigned through use of the isobaric analog resonance enhancements of the population of negative-parity final states. The systematic behavior of the 2−, 3− doublet and of the multiplet in these nuclei is discussed.
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Cited by (33)
Nuclear Data Sheets for A=98
2020, Nuclear Data SheetsExperimental spectroscopic data on nuclear structure and decay are evaluated for known nuclides of mass 98 (Br, Kr, Rb, Sr, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In). Detailed evaluation results of individual reactions and decays are presented together with the Adopted values that are recommended for level properties, γ and β radiations, and other spectroscopic information. 98Mo remains as the most extensively studied nuclide via various reactions and decays. Level schemes of Sr, Y, Zr, Tc, and Pd nuclides in this mass chain are also well established to date; while Kr, Rb, Nb, Ag and Cd are amongst the least-studied ones for excited states, with only limited data available for each. On the neutron-rich side, 98Br has been identified in the 9Be(238U,F) reaction, but no spectroscopic data are yet available, while for 98In on the proton-rich side, only the ground state and an isomer are known with half-lives measured but their spin-parities and the absolute level energy of the isomer yet to be determined. While 98Ru and 98Rh have also been extensively studied, large discrepancies exist between the high-spin sections of the proposed level schemes in different measurements, and these need to be clarified and resolved with further experimental investigations to improve the currently-adopted ones, which have been selected from the measurements with higher statistics, considering no other criteria of preference. This work supersedes all the earlier evaluations of A=98 (2003Si07, 1998Si18, 1992Si21, 1983Mu21, 1974Me34).
Study of gamma transitions and level scheme of <sup>94</sup>Nb using the <sup>93</sup>Nb(n<inf>th</inf>,2γ) reaction
2020, Nuclear Physics AIn this paper, we present new spectroscopic information on from the (,2γ) reaction. The intensities of the two-step gamma cascades in the compound nucleus to the final levels, with excitation energies below 400 keV, were derived from experimental spectra recorded at the PGAA facility of Centre for Energy Research (MTA EK), Budapest, Hungary. The intensities, energies of primary and secondary transitions of 216 energy-resolved cascades as well as intermediate cascade levels were determined. The part of the level scheme of was obtained from analyzing the intensity spectra of the strongest cascades. The results were compared to the existing data in the ENSDF database. We concluded that 27 primary transitions, 29 intermediate cascades levels as well as 183 secondary transitions can be recommended as new nuclear data.
Nuclear Data Sheets for A = 92
2012, Nuclear Data SheetsNuclear structure and decay data pertaining to all nuclides with mass number A = 92 (As, Se, Br, Kr, Rb, Sr, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd) have been compiled and evaluated, and incorporated into the ENSDF data file. All literature available by 15 September 2012 has been considered. This evaluation supersedes the previous publication for this mass chain (Coral M. Baglin, Nuclear Data Sheets 91, 423 (2000) (November 2000 cutoff date)), and subsequent unpublished reevaluations by C.M. Baglin for 92Kr (January 2004 literature cut-off) and 92Sr (August 2003 literature cut-off).
Nuclear data sheets for A = 95
2010, Nuclear Data SheetsExperimental data on ground and excited state properties for all known nuclei with mass number A=95 have been compiled and evaluated. States populated in radioactive decay, as well as in nuclear reactions, have been considered. For these nuclei, level and decay schemes, as well as tables of nuclear properties, are presented. This work supersedes the 1993 evaluation by T. W. Burrows (1993Bu08). In summary, three isomers were identified in 95Ag and their respective decay schemes were presented (2003Do09) though only limits on their half lives could be obtained. Besides, high resolution prompt gamma-spectroscopy of 95Ag has been reported for the first time (2003Ma24). A comprehensive level scheme 95Pd is now available through the ε decay of 95Ag (2005Ha45) and the energy of the 21/2+ spin-gap isomer have been established for the first time by observing the gamma-rays from the yrast levels (2003Ma24). The level scheme of 95Rh has been extended up to 39/2 h by in-beam spectroscopy (1994Ro08) and the γ-delayed proton decays from 96Ag isomers to low-lying levels in 95Pd have been observed (2003Ba39). The high spin level scheme of 95Ru has been extended up 43/2 h (1994Gh06) and the lifetime or lifetime limits of several high spin states have been reported (2004Ga08). In 95Tc, the level scheme has been extended by in-beam spectroscopy (2000Gh01). New data on high spin states in 95Mo have been available through in-beam spectroscopy using heavy ion reactions [(1998Kh04),(2004Ch18),(2009Zh11)]. The data on 95Nb has been considerably extended by (t,p) reaction (2005Ra30) and by (82Se,p2nγ) reaction (2005Bu08). In 95Zr, new measurements on μ (2005St24) and Q (1998Se01) have become available. Controversy on the existence of a 23 keV state in 95Zr has been resolved by a high-resolution measurement using magnetic spectrometer (2003So23). New data on high spin states have been published through heavy-ion induced fission [(2002Fo03), (2005Pa48)]. Very recently, new high spin data on 95Y by n-induced and spontaneous fission decay have been available (2009Ur02). High spin data on 95Sr have been reported by γ-spectroscopy of spontaneous fission decay (2004Hw04). In 95Rb, revised estimate of γ-n decay intensity (2002Pf04) and mass excess (2007Ra23) have been reported. New data on 85Kr it decay have been reported [(2006Ge05),(2007Si17)] and incorporated.
Nuclear Data Sheets for A = 97
2010, Nuclear Data SheetsThe 1993 evaluation of A = 97 (1993Ar09) was updated using data available prior to Nov. 19, 2009.
Nuclear Data Sheets for A = 96
2008, Nuclear Data SheetsExperimental data on ground- and excited-state properties for all known nuclei with mass number A = 96 have been compiled and evaluated. States populated in radioactive decay, as well as in nuclear reactions, have been considered. For these nuclei, level and decay schemes, as well as tables of nuclear properties, are presented. This work supersedes the 1993 evaluation by L.K. Peker (1993Pe02). In summary, three isomers were identified in 96Ag (2003Ba39,1997Gr02), even though the relative energies were not established. In 96Ru a nuclear fluorescence experiment (2005Li59) determined the spin, branching ratios and transition strengths of dipole excitations; high-spin level properties were reported by 2000Kh02 and 2002Kl07. High spin levels in 96Tc were studied in 2001Bu19. For 96Mo, there are new high-spin data (2000Ch42), as well as low-spin levels produced in () (2007Le05) and () (2004Fr30). High spin data (2005Pa48) were obtained for 96Zr using heavy-ion induced fission. For 96Sr, new levels were deduced using alpha-induced (2005Pa48) and spontaneous fission. The decay of a (10-) isomer in 96Rb was studied by 2005Pi13. Several new mass measurements for neutron rich nuclides have been published, which were used to obtain Q-values and separation energies.