| 1. |
- Kelsall, N. S., et al.
(författare)
-
Testing mean-field models near the N=Z line : gamma-ray spectroscopy of the T-z=1/2 nucleus Kr-73
- 2002
-
Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 65:4
-
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.
|
|
| 2. |
- Fischer, S. M., et al.
(författare)
-
Alignment delays in the N = Z nuclei Kr-72, Sr-76, and Zr-80
- 2001
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 8713:13
-
Tidskriftsartikel (refereegranskat)abstract
- The ground state rotational bands of the N = Z nuclei Kr-72, Sr-76, and Zr-80 have been extended into the angular momentum region where rotation alignment of particles is normally expected. By measuring the moments of inertia of these bands we have observed a consistent increase in the rotational frequency required to start pair breaking, when compared to neighboring nuclei. Kr-72 shows the most marked effect. It has been widely suggested that these delayed alignments arise from np-pairing correlations. However, alignment frequencies are very sensitive to shape degrees of freedom and normal pairing, so the new experimental observations are still open to interpretation.
|
|
| 3. |
- Wadsworth, R., et al.
(författare)
-
Terminating states in the positive-parity structures of As 67
- 2018
-
Ingår i: Physical Review C. - 2469-9985. ; 98:2
-
Tidskriftsartikel (refereegranskat)abstract
- The energy levels and γ-ray decay scheme of the positive-parity states in the Tz=12 nucleus As67 have been studied by using the Ca40(Ar36,2αp)As67 reaction at a beam energy of 145 MeV. Two new band structures have been identified which can be connected to the previously known levels. The results for these bands are compared with configuration-dependent cranked Nilsson-Strutinsky calculations. The good level of agreement between theory and experiment suggests that these structures can be interpreted in terms of configurations that involve three g92 particles and that both possess noncollective terminating states.
|
|
| 4. |
|
|
| 5. |
- Andersson, Lise-Lotte, et al.
(författare)
-
Gamma-ray Spectroscopy of Excited States in 61Zn
- 2006
-
Ingår i: European Physical Journal A. Hadrons and Nuclei. - : Springer Science and Business Media LLC. - 1434-6001. ; 30:2, s. 381-390
-
Tidskriftsartikel (refereegranskat)abstract
- The Zn-61(30)31 isotope has been produced at the Oak Ridge National Laboratory in the fusion-evaporation reaction Ca-40(Mg-24, 2pn)Zn-61 at 104 MeV. The experimental set-up allowed gamma-rays to be detected in the CLARION Ge detector array in coincidence with the detection of recoiling nuclei in the focal plane at the end of the recoil mass spectrometer. This provides a unique identification of gamma-rays belonging to Zn-61. The excited states have been explored by means of recoil-gamma gamma coincidences, and the resulting decay scheme comprises almost 70 transitions. The data reveal numerous non-yrast states and suggest a revised spin and parity assignment for a previously observed superdeformed band. The resulting decay scheme is compared to predictions from different sets of large-scale shell model calculations.
|
|
| 6. |
- Zhang, Xiaodong, et al.
(författare)
-
Characterizing the Timing Performance of a Fast 4H-SiC Detector With an 241Am Source
- 2013
-
Ingår i: IEEE Transactions on Nuclear Science. - : IEEE. - 0018-9499 .- 1558-1578. ; 60:3, s. 2352-2356
-
Tidskriftsartikel (refereegranskat)abstract
- An SPX4 4H-silicon carbide detector consisting of 4 x 4 pixels was developed and studied experimentally. Its pixel size is 400 μm x 400 μm . A timing resolution of 117 11 ps fullwidth at half-maximum (FWHM) has been measured for thedetection of alphas. With such good timing performance andhigh granularity, the SiC pixel detector holds great promise as anassociated alpha-particle detector for fast neutron imaging.
|
|
