| 1. |
- Pausch, G., et al.
(författare)
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RoSiB - a 4 pi silicon ball for charged-particle detection in EUROBALL
- 2000
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - 0168-9002 .- 1872-9576. ; 443:03-feb, s. 304-318
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Tidskriftsartikel (refereegranskat)abstract
- A 4 pi silicon bail for detection and identification of light charged particles in large multidetector gamma-arrays as EUROBALL is presented. The design is based on a N = 42 ball with 12 pentagons and 30 hexagons as used in the GASP array. The absorptive material for gamma-rays is minimized to the detector thickness of 300 or 500 mu m and a 0.63 mm ceramic backing. The geometrical coverage is designed for about 90% of 4 pi. A pulse shape discrimination method with totally depleted detectors working in the reverse mount allows identifying protons and alpha-particles above an energy threshold of about 2 MeV. The performances of the ball were rested at the tandem - booster accelerator combination of the MPI Heidelberg in two experiments using the high-recoil reaction of 228 MeV Ni-58 + Ti-46 and the low-recoil reaction of 95 MeV O-16 + Ni-58. The two-dimensional spectra of zero-crossing (ZC) versus energy confirmed an excellent discrimination of protons and alpha-particles in all the detectors at different angles. The energy spectra of protons and alpha-particles measured in the experiments are presented. too. The gamma-spectra measured in coincidence with various combinations of emitted particles showed a high selectivity of the ball. The reduced total efficiency for protons of 59% and 55% and alpha-particles of 44% and 32% measured in a nuclear spectroscopy application is analyzed in a Monte-Carlo simulation (GEANT). It is due to a combined influence of a thick target needed to stop the recoiling residual nuclei and thick absorbers needed to protect the Si-detectors from scattered beam. The results along with the GEANT extrapolation to optimum experimental conditions confirm that RoSiB is a highly efficient and selective device for identification of rare reaction channels with heavy ions.
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| 2. |
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| 3. |
- Pausch, G, et al.
(författare)
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RoSiB - a 4 pi silicon ball for charged-particle detection in EUROBALL
- 2000
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Ingår i: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT. - : ELSEVIER SCIENCE BV, AMSTERDAM. - 0168-9002. ; 443:2-3, s. 304-318
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Tidskriftsartikel (refereegranskat)abstract
- A 4 pi silicon bail for detection and identification of light charged particles in large multidetector gamma-arrays as EUROBALL is presented. The design is based on a N = 42 ball with 12 pentagons and 30 hexagons as used in the GASP array. The absorptive
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| 4. |
- Borcan, C, et al.
(författare)
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First identification of excited states in the N = Z nucleus Br-70
- 1999
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Ingår i: EUROPEAN PHYSICAL JOURNAL A. - : SPRINGER VERLAG. ; 5:3, s. 243-246
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Excited states in the T-z = 0 nucleus Br-70 have been investigated using the reaction Ni-58(O-16,1p3n). gamma rays were detected with one EUROBALL CLUSTER detector and three single HPGe detectors. Charged particles and neutrons were registered with the Ro
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| 5. |
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| 6. |
- Lane, G. J., et al.
(författare)
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Identification of excited states in doubly odd [Formula Presented]Sb : Smooth band termination
- 1997
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Ingår i: Physical Review C - Nuclear Physics. - 0556-2813. ; 55:5, s. 2127-2131
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Tidskriftsartikel (refereegranskat)abstract
- Excited states in [Formula Presented]Sb have been identified for the first time in a series of [Formula Presented]-spectroscopy experiments using both thin and backed targets, including neutron-fold and recoil-mass measurements to provide unambiguous channel identification. The three decoupled intruder bands observed in [Formula Presented]Sb are based upon configurations involving 2p-2h excitations across the [Formula Presented] shell gap and show the features of smooth band termination. The yrast intruder band, which has been connected to the low-spin levels, is tentatively identified up to its predicted termination at [Formula Presented]. Excellent agreement with configuration-dependent cranked Nilsson-Strutinsky calculations is obtained for the high-spin states near termination.
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| 7. |
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| 8. |
- Plettner, C., et al.
(författare)
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Very high rotational frequencies and band termination in 73Br
- 2000
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Ingår i: Physical Review C - Nuclear Physics. - 0556-2813. ; 62:1, s. 143131-143136
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Tidskriftsartikel (refereegranskat)abstract
- Rotational bands in 73Br have been investigated up to spins of I = 65/2 using the EUROBALL III spectrometer. One of the negative-parity bands displays the highest rotational frequency ℏω= 1.85 MeV reported to date in nuclei with A ≥ 25. At high frequencies, the experimental J(2) dynamic moment of inertia for all bands decreases to very low values, J(2) ≤ 10ℏ2 MeV-1. The bands are described in the configuration-dependent cranked Nilsson-Strutinsky model. The calculations indicate that one of the negative-parity bands is observed up to its terminating single-particle state at spin 63/2. This result establishes the first band termination in the A ≈ 70 mass region.
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| 9. |
- Rainovski, G, et al.
(författare)
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Shape coexistence at high spin in the N = Z+2 nucleus Se-70
- 2002
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Ingår i: Journal of Physics G: Nuclear and Particle Physics. - : IOP Publishing. - 0954-3899. ; 28:10, s. 2617-2625
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Tidskriftsartikel (refereegranskat)abstract
- The nucleus Se-70 was studied using the Ca-40(Ca-40, 2alpha2p) reaction at a beam energy of 185 MeV. Gamma rays were measured with the EUROBALL III spectrometer. The known positive-parity bands have been extended and one new band of positive parity and two of negative parity have been identified. These bands are interpreted in terms of the cranked Nilsson-Strutinsky approach. Calculations suggest that the two negative-parity bands, which have the same signature, are both based on a configuration with two protons and three neutrons lifted from the fp shell to the g(9/2) orbital, but at different nuclear shapes. This represents a shape coexistence at high spin.
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| 10. |
- Thorslund, I., et al.
(författare)
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Intruder bands in Te114 : Smooth band termination
- 1995
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Ingår i: Physical Review C. - 0556-2813. ; 52:6, s. 2839-2843
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Tidskriftsartikel (refereegranskat)abstract
- The nucleus Te114 has been studied in heavy-ion -ray spectroscopy experiments performed with the early implementation of the GAMMASPHERE multidetector array. Three rotational intruder bands have been observed up to high spins. The yrast band, involving the 4p2h (h11/2)2(g7/2)2(g9/2)-2 proton configuration, reaches I=48Latin small letter h with stroke at an excitation energy of 30.3 MeV, the highest observed spin connected by rays in this mass region. The band properties are interpreted in the framework of smooth band termination.
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| 11. |
- Valiente-Dobon, JJ, et al.
(författare)
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Evidence for nontermination of rotational bands in Kr-74
- 2005
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Ingår i: Physical Review Letters. - 1079-7114. ; 95:23
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Tidskriftsartikel (refereegranskat)abstract
- Three rotational bands in Kr-74 were studied up to (in one case one transition short of) the maximum spin I-max of their respective single-particle configurations. Their lifetimes have been determined using the Doppler-shift attenuation method. The deduced transition quadrupole moments reveal a modest decrease, but far from a complete loss of collectivity at the maximum spin I-max. This feature, together with the results of mean field calculations, indicates that the observed bands do not terminate at I=I-max.
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