Nuclear Data Sheets for A = 106 De Frenne, D.; Negret, A.
Nuclear data sheets,
04/2008, Letnik:
109, Številka:
4
Journal Article
Recenzirano
The 1994 evaluation on mass A = 106 has been revised, taking into account all data available before May 2007. Detailed experimental information is presented from the neutron rich nucleus
106Y to the ...neutron deficient
106Te nucleus. All conversion coefficients have been calculated with BRICC.
Isospin symmetry is expected for the T(z)=+/-1-->0 isobaric analogous transitions in isobars with mass number A, where T(z) is the z component of isospin T. Assuming this symmetry, strengths of ...analogous Gamow-Teller (GT) transitions within A = 50 isobars were determined from a high energy-resolution study at 0 degrees in combination with the decay Q value and lifetime from the beta decay. This method can be applied to other pf-shell nuclei and can be used to study GT strengths of astrophysical interest.
Gamow-Teller (GT) transitions in atomic nuclei are sensitive to both nuclear shell structure and effective residual interactions. The nuclear GT excitations were studied for the mass number A = 42, ...46, 50, and 54 "f-shell" nuclei in ((3)He, t) charge-exchange reactions. In the (42)Ca → (42)Sc reaction, most of the GT strength is concentrated in the lowest excited state at 0.6 MeV, suggesting the existence of a low-energy GT phonon excitation. As A increases, a high-energy GT phonon excitation develops in the 6-11 MeV region. In the (54)Fe → (54)Co reaction, the high-energy GT phonon excitation mainly carries the GT strength. The existence of these two GT phonon excitations are attributed to the 2 fermionic degrees of freedom in nuclei.
The 1998 evaluation on mass A = 102 (1998De15) has been revised, taking into account all data available before december 2008. Detailed experimental information is presented from the neutron rich ...nucleus
102Rb to the neutron deficient
102Sn nucleus. No information on excited states of
102Rb is available and very scarce for
102Sr Especially new (HI,xnγ) data sets for several nuclides have been evaluated and new and more accurate data for γ intensities and multipolarities obtained. For
102Ru very precise new data of the Budapest (n,γ) collaboration have been included.A new and very elaborated decay scheme for
102In is obtained. Isomerism in
102Y and
102Nb needs further investigation due to conflicting results.
Nuclear Data Sheets for A = 105 De Frenne, D.; Jacobs, E.
Nuclear data sheets,
08/2005, Letnik:
105, Številka:
4
Journal Article
Recenzirano
Odprti dostop
The 1993 evaluation on mass A = 105 has been revised, taking into account all data available before September 2004. Detailed experimental information is presented from the neutron rich nucleus
105Zr ...to the neutron deficient
105Sb nucleus. Especially several (HI,xnγ) data sets to obtain the excited levels for the proton rich nuclides have been evaluated.
The 2001 evaluation on mass A = 103 (2001De37) has been revised, taking into account all data available before March 2009. Experimental information is presented from the neutron rich nucleus
103Sr to ...the neutron deficient
103Sn nucleus. The experimental information on excited states for
103Sr and
103y is very scarce New (HI, xnγ) data sets for several nuclides have been evaluated and new and more accurate data for γ intensities and multipolarities obtained. The BRICC code has been used for the calculation of conversion coefficients.
The mainstream forestry policy in many European countries is to convert coniferous plantations into (semi-natural) deciduous woodlands. However, woodlands are the main habitat for Ixodes ricinus ...ticks. Therefore, assessing to what extent tick abundance and infection with Borrelia spirochetes are affected by forest composition and structure is a prerequisite for effective prevention of Lyme borreliosis. We selected a total of 25 pine and oak stands, both with and without an abundant shrub layer, in northern Belgium and estimated tick abundance between April and October 2008-2010. Additionally, the presence of deer beds was used as an indicator of relative deer habitat use. Borrelia infections in questing nymphs were determined by polymerase chain reactions. The abundance of larvae, nymphs, and adults was higher in oak stands compared to pine stands and increased with increasing shrub cover, most likely due to differences in habitat use by the ticks' main hosts. Whereas tick abundance was markedly higher in structure-rich oak stands compared to homogeneous pine stands, the Borrelia infection rates in nymphs did not differ significantly. Our results indicate that conversion towards structure-rich deciduous forests might create more suitable tick habitats, but we were unable to detect an effect on the infection rate.
A new experimental approach to the famous problem of the anomalously slow Gamow-Teller (GT) transitions in the beta decay of the A=14 multiplet is presented. The GT strength distributions to excited ...states in 14C and 14O were studied in high-resolution (d,2He) and (3He,t) charge-exchange reactions on 14N. No-core shell-model calculations capable of reproducing the suppression of the beta decays predict a selective excitation of Jpi=2+ states. The experimental confirmation represents a validation of the assumptions about the underlying structure of the 14N ground state wave function. However, the fragmentation of the GT strength over three 2+ final states remains a fundamental issue not explained by the present no-core shell model using a 6homega model space, suggesting possibly the need to include cluster structure in these light nuclei in a consistent way.
Spin–isospin excitations of the medium-mass nucleus 58Co were studied using the (n,p)-type (d,2He) charge-exchange reaction at an incident energy Ed=170 MeV and small scattering angles. The achieved ...energy resolution of 130 keV, full width at half maximum, allowed the extraction of Gamow–Teller strength to 13 peaks at excitation energies lower than 4.1 MeV in the residual nucleus 58Co and is consistent with the results of a multipole-decomposition analysis. The identification of Gamow–Teller transitions is possible by comparison of the measured cross sections with DWBA calculations. The results are used to discuss the relevance of the Gamow–Teller strength distribution at low excitation energy with regard to electron-capture rates used in calculations for the final stage of a massive star.
In general, the EPR spectra of irradiated sugars are very complex because of their multicomponent character. In this study we applied a multivariate statistical method called MLCFA, maximum ...likelihood common factor analysis, and it predicted at least six components contributing to the total EPR spectrum of irradiated sucrose. Three dominant components have already been isolated in an irradiated sucrose single crystal using electron nuclear double resonance (ENDOR) and ENDOR induced EPR (EI-EPR). Results of EPR simulations based on the ENDOR data are in a reliable agreement with the experimental EPR spectra of irradiated sucrose single crystals.
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