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| 2. |
- Henderson, J., et al.
(författare)
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Coulomb excitation of the vertical bar T-z vertical bar=1/2, A=23 mirror pair
- 2022
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Ingår i: PHYSICAL REVIEW C. - 2469-9985 .- 2469-9993. ; 105:3
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Tidskriftsartikel (refereegranskat)abstract
- Background: Electric-quadrupole (E2) strengths relate to the underlying quadrupole deformation of a nucleus and present a challenge for many nuclear theories. Mirror nuclei in the vicinity of the line of N = Z represent a convenient laboratory for testing deficiencies in such models, making use of the isospin symmetry of the systems. Purpose: Uncertainties associated with literature E2 strengths in Mg-23 are some of the largest in T-z = vertical bar 1/2 vertical bar nuclei in the sd shell. The purpose of the present paper is to improve the precision with which these values are known, to enable better comparison with theoretical models. Methods: Coulomb-excitation measurements of Mg-23 and Na-23 were performed at the TRIUMF-ISAC facility using the TIGRESS spectrometer. They were used to determine the E2 matrix elements of mixed E2/M1 transitions. Results: Reduced E2 transition strengths, B(E2), were extracted for Mg-23 and Na-23. Their precision was improved by factors of approximately 6 for both isotopes, while agreeing within uncertainties with previous measurements. Conclusions: A comparison was made with both shell-model and ab initio valence-space in-medium similarity renormalization group calculations. Valence-space in-medium similarity renormalization group calculations were found to underpredict the absolute E2 strength, in agreement with previous studies.
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| 3. |
- Moukaddam, M., et al.
(författare)
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In-beam internal conversion electron spectroscopy with the SPICE detector
- 2018
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Ingår i: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. - : Elsevier BV. - 0168-9002. ; 905, s. 180-187
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Tidskriftsartikel (refereegranskat)abstract
- The SPectrometer for Internal Conversion Electrons (SPICE) has been commissioned for use in conjunction with the TIGRESS γ-ray spectrometer at TRIUMF's ISAC-II facility. SPICE features a permanent rare-earth magnetic lens to collect and direct internal conversion electrons emitted from nuclear reactions to a thick, highly segmented, lithium-drifted silicon detector. This arrangement, combined with TIGRESS, enables in-beam γ-ray and internal conversion electron spectroscopy to be performed with stable and radioactive ion beams. Technical aspects of the device, capabilities, and initial performance are presented.
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| 4. |
- Orce, J. N., et al.
(författare)
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Reorientation-effect measurement of the (2+ 1 Eˆ22+ 1) matrix element in 10Be
- 2012
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Ingår i: Physical Review C - Nuclear Physics. - 2469-9985 .- 2469-9993. ; 86:4
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Tidskriftsartikel (refereegranskat)abstract
- The highly-efficient and segmented TIGRESS gamma-ray spectrometer at TRIUMF has been used to perform a reorientation-effect Coulomb-excitation study of the 2(1)(+) state at 3.368 MeV in Be-10. This is the first Coulomb-excitation measurement that enables one to obtain information on diagonal matrix elements for such a high-lying first excited state from gamma-ray data. With the availability of accurate lifetime data, a value of -0.110 +/- 0.087 eb is determined for the diagonal matrix element, which assuming the rotor model, leads to a negative spectroscopic quadrupole moment of Q(S)(2(1)(+)) = -0.083 +/- 0.066 eb. This result is in agreement with both no-core shell-model calculations performed in this work with the CD-Bonn 2000 two-nucleon potential and large shell-model spaces, and Green's function Monte Carlo predictions with two-plus three-nucleon potentials.
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| 5. |
- Svensson, C. E., et al.
(författare)
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Decay Out of the Doubly Magic Superdeformed Band in the N=Z Nucleus 60Zn
- 1999
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Ingår i: Physical Review Letters. - 1079-7114. ; 82:17, s. 3400-3403
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Tidskriftsartikel (refereegranskat)abstract
- The doubly magic superdeformed band in the N = Z nucleus Zn-60 has been identified. Linking transitions connecting this band to the yrast line provide the first spin, parity, and excitation energy measurements for superdeformed states in the A similar to 60 region. The stretched-E2 character and relatively large B(E2) values of these transitions suggest a nonstatistical decay-out process.
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| 6. |
- Yu, C. H., et al.
(författare)
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Comparison of Superdeformed Bands in 61Zn and 60Zn: Possible Evidence for T=0 Pairing
- 1999
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 60:3
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Tidskriftsartikel (refereegranskat)abstract
- The yrast superdeformed band in Zn-61 has been established using Si-28(Ar-36, 2pn)Zn-61 and Ca-40(Si-29, 2 alpha)Zn-61 fusion-evaporation reactions. The excitation energy of this band was determined via two transitions that link this band to the normally deformed states. Lifetime analysis of this band resulted in a quadrupole moment of Q(t) = 3.0 +/- (0.5)(0.4)e b, which corresponds to a deformation of beta(2) = 0.50+/-(0.07)(0.06). A comparison of the J((2)) dynamical moments of inertia of the yrast superdeformed band in Zn-61 with those in Zn-60 shows a nearly complete blocking of the observed alignment in Zn-60, indicating that T=0 proton-neutron pair correlations may be present in Zn-60. [S0556-2813(99)51109-6].
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| 7. |
- Yu, C. H., et al.
(författare)
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Superdeformed and Highly Deformed Bands in 65Zn and Neutron-proton Interactions in Zn Isotopes
- 2000
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 62:4
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Tidskriftsartikel (refereegranskat)abstract
- Superdeformed and highly deformed rotational bands were established in Zn-65 using the Ca-40(Si-29,4p)Zn-65 reaction, and averaged quadrupole moments were measured for two of these bands. The configurations of these bands were assigned based on Hartree-Fock calculations. One of the three bands exhibits at low (h) over bar omega a rise in the J((2)) dynamic moments of inertia that is similar to the alignment gain observed in Zn-60. A comparison of the rotational band configurations and their J((2)) moments of inertia for light Zn isotopes suggests that the rise in J((2)) is most likely caused by np interactions associated with the valence protons and neutrons occupying the g(9/2) intruder orbits.
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| 8. |
- Gellanki, Jnaneswari, et al.
(författare)
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Characterization of Superdeformed Bands in 62Zn
- 2009
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 80:5
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Tidskriftsartikel (refereegranskat)abstract
- Combined data from four fusion-evaporation reaction experiments were utilized to investigate deformed and superdeformed structures in Zn-62(30)32. Combination of the Gammasphere gamma-ray spectrometer and ancillary particle detection systems allowed for the connection of rotational bands to well-known, low-lying excited states in Zn-62, as well as spectroscopy of discrete high-spin states reaching excitation energies of E-x=42.5 MeV. Four well- or superdeformed bands in Zn-62 are characterized and described by means of cranked Nilsson-Strutinsky calculations.
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| 9. |
- Kelsall, N. S., et al.
(författare)
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Testing mean-field models near the N=Z line : gamma-ray spectroscopy of the T-z=1/2 nucleus Kr-73
- 2002
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 65:4
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Tidskriftsartikel (refereegranskat)abstract
- Excited states in the N=Z+1 nucleus Kr-73 have been investigated using the Ca-40(Ar-36,2pn) and Ca-40(Ca-40,alpha2pn) reactions at 145 and 160 MeV, respectively. gamma rays were detected using the Gammasphere array and events were recorded in coincidence with charged-particle and neutron detectors. The three previously observed bands were extended to high spin, and a new unfavored positive-parity band has been observed. The alignment characteristics and decay properties of the bands are all consistent with large-deformation prolate rotation, with no clear evidence for oblate bands or shape coexistence. This is quite different from neighboring Kr-72,Kr-74, indicating a strong shape-stabilizing role for the valence neutron. The experimental results are compared to extended total Routhian surface, cranked Nilsson Strutinsky, and cranked relativistic mean-field calculations. The results suggest that the paired calculations lack some important physics. Neutron-proton correlations may be the missing ingredient. There is also evidence for an unusual band crossing in the negative-parity bands, which may indicate the presence of T=0 pairing correlations. At high spin all the models can reproduce the experimental data.
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| 10. |
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