| 1. |
- Fujita, Y, et al.
(författare)
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Evidence for the existence of the [202]3/2 deformed band in mirror nuclei Mg-25 and Al-25
- 2004
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Ingår i: Physical Review Letters. - 1079-7114. ; 92:6
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Tidskriftsartikel (refereegranskat)abstract
- After 50 years of its prediction, the highest-lying [2 0 2]3/2 orbit among the six Nilsson single-particle orbits originating from the sd shells in prolately deformed nuclei and the rotational band on this orbit were identified. The band members were observed in Al-25 at excitation energies of 6-7.5 MeV in a high-resolution Mg-25(He-3,t) charge-exchange reaction at 0degrees having a strong selectivity for Gamow-Teller transitions. In the comparison with the analogous M1 transitions in Mg-25, the J(pi)=3/2(+) bandhead state and the excited 5/2(+) and 7/2(+) members were clearly assigned.
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| 2. |
- Shimbara, Y, et al.
(författare)
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Suppression of Gamow-Teller and M1 transitions in deformed mirror nuclei Mg-25 and Al-25 - Direct observation of K selection rules
- 2004
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Ingår i: European Physical Journal A. Hadrons and Nuclei. - : Springer Science and Business Media LLC. - 1434-6001. ; 19:1, s. 25-31
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Tidskriftsartikel (refereegranskat)abstract
- The mirror nuclei Mg-25 and Al-25 are expected to have very similar structures. The Gamow-Teller (GT) transitions from the J(pi) = 5/2(+) ground state of Mg-25 to the excited states in Al-25 were studied by high-resolution measurements of the Mg-25(He-3,t) charge-exchange reaction at 0degrees and at 140 MeV/nucleon. Assuming the usual DeltaJ(pi) = 1(+) selection rule for the spin-isospin-type GT transitions, the states with J(pi) = 3/2(+), 5/2(+), and 7/2 (+) should be excited. However, of the more than ten states with these J(pi) values below 6 MeV excitation energy, only the 5/2 (+) ground state and the 7/2 (+) , 1.613 MeV state in Al-25 were strongly populated, while all other states were strongly suppressed. The analysis of M1 transitions in Mg-25 also suggested a very similar feature for the analogous M1 transitions. Both Mg-25 and Al-25 are known to be largely deformed, and most low-lying states can be interpreted in terms of one-particle quantum numbers in the deformed potential and the associated rotational spectra. The observed suppression can be explained in terms of the K quantum number selection rules that are inherent to axially deformed nuclei.
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| 3. |
- Sips, A. C. C., et al.
(författare)
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An international database for the study of the formation of ITBs in tokamaks
- 2002
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Ingår i: Plasma Physics and Controlled Fusion. - 0741-3335 .- 1361-6587. ; 44, s. A391-A398
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Tidskriftsartikel (refereegranskat)abstract
- For the first time, data from eight,different tokamaks have been combined in an international database for internal transport barriers (ITBs). An analysis of the data for the formation of an ITB with dominant ion heating shows a clear dependence of the threshold power on the minor radius and line-averaged electron density for the formation of ion ITBs. The dependence of ITB formation on the toroidal magnetic field is weak. For the formation of ITBs with dominant electron heating, the database is smaller, but for the threshold power a strong increase with plasma size and a weak toroidal field dependence could also be identified. Based on these results, an expression for the power required to form an ITB is given using global variables only. These results give a basis for the analysis of the database using local values (like magnetic shear) and a detailed comparison with theory-based models.
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| 4. |
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