| 1. |
- Bjornstad, T., et al.
(författare)
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Study of the Giant Gamow-Teller Resonance in Nuclear Beta-Decay - the Case of Ar-32
- 1985
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Ingår i: Nuclear Physics A. - : Elsevier BV. - 0375-9474. ; 443:2, s. 283-301
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Tidskriftsartikel (refereegranskat)abstract
- Delayed proton and gamma emissions following the β-decay of 32Ar have been studied. The half-life of 32Ar is 98 ± 2 ms, and the T = 2 analogue state in 32Cl lies at the excitation energy 5036 ± 12 keV. From the intensity of the feeding to this state the proton intensities can be converted to an absolute scale leading to a total proton branching ratio of (43 ± 3)%. From proton-gamma coincidence measurements it emerges that (1.9 ± 0.2)% of the protons lead to the first-excited state in 31S. A level scheme up to 8.75 MeV excitation in 32Cl has been constructed and the Gamow-Teller strength function has been deduced. The result is a renormalization of the axial-vector strength to (49 ± 5)% of the free-nucleon value.
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| 2. |
- Bjornstad, T., et al.
(författare)
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The Doubly Closed Shell Nucleus Sn-132(50)82
- 1986
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Ingår i: Nuclear Physics A. - : Elsevier BV. - 0375-9474. ; 453:3, s. 463-485
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Tidskriftsartikel (refereegranskat)abstract
- The structure of excited states in 132Sn, fed in the β-decay of 132In, has been investigated. Absolute intensities were deduced from γ-singles measurements. From multi-spectrum analysis of γ-lines the half-life of 132In was determined to be 186 ± 22 ms. A level scheme based on γγ and βγ coincidences is presented. The conversion electron spectrum has been studied and internal conversion coefficients deduced for two low-energy transitions. The total decay energy of 132In was determined, from γ-gated β-spectra, to be Qβ = 13.6 ± 0.4 MeV. A lower limit of 6.968 MeV for the neutron separation energy in 132Sn was deduced from the β-delayed neutron spectrum. The experimental results on the level structure of the doubly closed shell nucleus 132Sn show that the shell model is applicable even far from the valley of stability.
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| 3. |
- Borge, M. J. G., et al.
(författare)
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Beta-Delayed Proton and Alpha Emission in the Decay of Ne-17
- 1988
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Ingår i: Nuclear Physics A. - : Elsevier BV. - 0375-9474. ; 490:2, s. 287-306
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Tidskriftsartikel (refereegranskat)abstract
- The beta-delayed proton and alpha spectra from 17Ne have been studied with Si-detectors. The Gamow-Teller strength in the decay of 17Ne has been extracted and compared with a two-particle-one-hole shell-model calculation. The experimental strength is quenched by a factor of 0.82 with respect to the calculated one. Furthermore, the decay scheme has been improved and is discussed in some detail. The proton emitting levels in 17F are very broad and the line shapes are strongly influenced by phase-space effects. Interference between peaks corresponding to the same intermediate spin is a prominent feature emerging clearly with the good resolution and statistics of the present work.
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| 4. |
- Borge, M. J. G., et al.
(författare)
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Beta-Delayed Triton Emission in the Decay of He-8
- 1986
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Ingår i: Nuclear Physics A. - : Elsevier BV. - 0375-9474. ; 460:3, s. 373-380
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Tidskriftsartikel (refereegranskat)abstract
- A β-delayed triton branch with an intensity of (0.9 ± 0.1)% has been observed in the decay of 8He. The triton energy spectrum was measured with a specially designed ΔE − E telescope. These data as well as an earlier measured β-delayed neutron spectrum cannot be explained from the known levels in 8Li, but it turns out that the main features of both the delayed triton and the delayed neutron spectra from 8He could be understood if one assumes a new state in 8Li at about 8.8 MeV excitation energy.
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| 5. |
- Sümmerer, K., et al.
(författare)
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Levels in 106Ru and 108Ru
- 1980
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Ingår i: Nuclear Physics A. - : Elsevier BV. - 0375-9474. ; 339:1, s. 74-88
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Tidskriftsartikel (refereegranskat)abstract
- The decay schemes of 36 s 106Tc and 5 s 108Tc have been studied with γ-ray singles and γ-γ coincidence measurements. To separate the technetium nuclides from the fission products of 239Pu, an on-line chemical separation procedure has been developed which is based on multistep chemical separations of liquid phases by fast-rotating centrifuges (“SISAK”). The resulting level schemes of 106Ru and 108Ru, together with those of 102Ru and 104Ru, are interpreted in terms of the generalized collective model of Gneuss and Greiner. The potential-energy surfaces calculated from the spectroscopic data show a trend towards triaxial shapes for the very neutron-rich Ru nuclei.
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| 6. |
- Skarnemark, Gunnar, 1948
(författare)
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Levels in 109Rh
- 1987
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Ingår i: Nucl. Phys.. - : Elsevier BV. ; :470, s. 141-
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Tidskriftsartikel (refereegranskat)abstract
- The levels in 109Rh have been investigated via the γ-rays following the β− decay of 34.5 s 109Ru. The ruthenium activity was produced in the thermal neutron-induced fission of 149Cf and separated chemically from the fission product mixture with the on-line centrifuge system SISAK. The emitted γ-rays were studied by γ singles and γγ(t) coincidence measurements. In addition, the 110Pd(d, 3He) reaction was investigated at Ed = 50 MeV to study the proton-hole states in 109Rh. From the comparison of the measured angular distributions with DWBA calculations l-transfers and spectroscopic factors were deduced. The level scheme of 109Rh that was obtained is discussed and compared with neighbouring nuclei and with recent calculations in the framework of the interacting bosonfermion model (IBFM-1). An interpretation of the observed candidates for intruder states as a rotational band built upon the [431] Nilsson configuration is proposed.
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| 7. |
- Skarnemark, Gunnar, 1948
(författare)
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Levels of 107Rh
- 1986
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Ingår i: Nucl. Phys. - : Elsevier BV. ; A460, s. 437-
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Tidskriftsartikel (refereegranskat)abstract
- The levels in 107Rh have been investigated via the γ-rays following the β− decay of 3.75 min 107Ru. The ruthenium activity was produced in the thermal neutron-induced fission of 239Pu and separated chemically from the fission product mixture with the on-line centrifuge system SISAK. The emitted γ-rays were studied by γ singles and γγ(t) coincidence measurements. In addition, the 108Pd(d, 3He) reaction was investigated at Ed = 50 MeV to study the proton-hole states in 107Rh. From the comparison of the measured angular distributions with DWBA calculations l-transfers and spectroscopic factors were deduced. The obtained level scheme of 107Rh is discussed and compared with neighbouring nuclei and with recent calculations in the framework of the interacting boson-fermion (IBFM-1) model.
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| 8. |
- Skarnemark, Gunnar, 1948
(författare)
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The Decay 150Pr 150Nd and the Anomalous -Band in 150Nd
- 1986
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Ingår i: Nucl. Phys. - : Elsevier BV. ; A453, s. 15-
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Tidskriftsartikel (refereegranskat)abstract
- The β-decay of mass-separated 150Pr has been studied resulting in a considerably improved level scheme for 150Nd. Particular care has been taken to evaluate the γ-ray branching ratios from the 2+ levels of the β- and γ-bands since the moment of inertia of the β-band in 150Nd deviates considerably from the systematics of the N = 90 isotones. The deduced relative B(E2) values from the β-band are in keeping with a relatively small deformation for this band.
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| 9. |
- Dodig Crnkovic, Gordana, 1955
(författare)
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Absolute Alpha-decay Rates in Po Isotopes
- 1985
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Ingår i: Nuclear Physics A. - 0375-9474. ; 444, s. 419-435
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Tidskriftsartikel (refereegranskat)abstract
- Absolute a-decay widths in Po isotopes are studied in terms of a correlated basis consisting of two-particle (physical) states. It is found that the neutron-neutron, proton-proton and neutron-proton pairing interactions play a fundamental role in clustering the neutrons and protons thateventually constitute the alpha-particle. As a result, the calculated alpha-decay widths are enhanced by several orders of magnitude by properly including the pairing interaction. Reasonable agreement with available experimental data is obtained.
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| 10. |
- Dodig Crnkovic, Gordana, 1955, et al.
(författare)
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An exact shell-model treatment of Alpha-clustering and absolute Alpha-decay
- 1989
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Ingår i: Nuclear Physics A. - 0375-9474. ; 501:3, s. 533-545
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Tidskriftsartikel (refereegranskat)abstract
- The alpha clustering and corresponding alpha decay of 212Po is studied within the framework of a multistep shell-model method. All interactions among the four nucleons that constitute the alpha particle are included and a large single-particle representation is used.
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