| 1. |
- Warr, N., et al.
(författare)
-
The Miniball spectrometer
- 2013
-
Ingår i: European Physical Journal A. Hadrons and Nuclei. - : Springer Science and Business Media LLC. - 1434-6001. ; 49:3
-
Tidskriftsartikel (refereegranskat)abstract
- The Miniball germanium detector array has been operational at the REX (Radioactive ion beam EXperiment) post accelerator at the Isotope Separator On-Line facility ISOLDE at CERN since 2001. During the last decade, a series of successful Coulomb excitation and transfer reaction studies have been performed with this array, utilizing the unique and high-quality radioactive ion beams which are available at ISOLDE. In this article, an overview is given of the technical details of the full Miniball setup, including a description of the.-ray and particle detectors, beam monitoring devices and methods to deal with beam contamination. The specific timing properties of the REX-ISOLDE facility are highlighted to indicate the sensitivity that can be achieved with the full Miniball setup. The article is finalized with a summary of some physics highlights at REX-ISOLDE and the utilization of the Miniball germanium detectors at other facilities.
|
|
| 2. |
- de Walle, J. V., et al.
(författare)
-
Coulomb excitation of the N=50 nucleus Zn-80
- 2008
-
Ingår i: AIP Conference Proceedings. - 1551-7616 .- 0094-243X. ; 1012, s. 291-295 453
-
Konferensbidrag (refereegranskat)abstract
- Neutron rich Zinc isotopes, including the N=50 nucleus Zn-80, were produced and post-accelerated at the Radioactive Ion Beam (RIB) facility REX-ISOLDE (CERN). Low-energy Coulomb excitation was induced on these isotopes after post-acceleration, yielding B(E2) strengths to the first excited 2(+) states. For the first time, an excited state in Zn-80 was observed and the 2(1)(+) state in Zn-78 was established. The measured B(E2,2(1)(+) -> 0(1)(+)) values are compared to two sets of large scale shell model calculations. Both calculations reproduce the observed B(E2) systematics for the full Zinc isotopic chain. The results for N=50 isotones indicate a good N=50 shell closure and a strong Z=28 proton core polarization. The new results serve as benchmarks to establish theoretical models, predicting the nuclear properties of the doubly magic nucleus Ni-78.
|
|
| 3. |
- Van de Walle, J., et al.
(författare)
-
Coulomb excitation of neutron-rich Zn isotopes: First observation of the 2(1)(+) state in Zn-80
- 2007
-
Ingår i: Physical Review Letters. - 1079-7114. ; 99:14
-
Tidskriftsartikel (refereegranskat)abstract
- Neutron-rich, radioactive Zn isotopes were investigated at the Radioactive Ion Beam facility REX-ISOLDE (CERN) using low-energy Coulomb excitation. The energy of the 2(1)(+) state in Zn-78 could be firmly established and for the first time the 2(+)-> 0(1)(+) transition in Zn-80 was observed at 1492(1) keV. B(E2,2(1)(+)-> 0(1)(+)) values were extracted for Zn-74,Zn-76,Zn-78,Zn-80 and compared to large scale shell model calculations. With only two protons outside the Z=28 proton core, Zn-80 is the lightest N=50 isotone for which spectroscopic information has been obtained to date. Two sets of advanced shell model calculations reproduce the observed B(E2) systematics. The results for N=50 isotones indicate a good N=50 shell closure and a strong Z=28 proton core polarization. The new results serve as benchmarks to establish theoretical models, predicting the nuclear properties of the doubly magic nucleus Ni-78.
|
|
| 4. |
- Walle, J. Van de, et al.
(författare)
-
Coulomb Excitation of Neutron-Rich Zn Isotopes: First Observation of the 2[sub 1][sup +] State in [sup 80]Zn
- 2007
-
Ingår i: Physical Review Letters. ; 99:14, s. 142501-
-
Tidskriftsartikel (refereegranskat)abstract
- Neutron-rich, radioactive Zn isotopes were investigated at the Radioactive Ion Beam facility REX-ISOLDE (CERN) using low-energy Coulomb excitation. The energy of the 21+ state in 78Zn could be firmly established and for the first time the 2+-->01+ transition in 80Zn was observed at 1492(1) keV. B(E2,21+-->01+) values were extracted for 74,76,78,80Zn and compared to large scale shell model calculations. With only two protons outside the Z=28 proton core, 80Zn is the lightest N=50 isotone for which spectroscopic information has been obtained to date. Two sets of advanced shell model calculations reproduce the observed B(E2) systematics. The results for N=50 isotones indicate a good N=50 shell closure and a strong Z=28 proton core polarization. The new results serve as benchmarks to establish theoretical models, predicting the nuclear properties of the doubly magic nucleus 78Ni.
|
|
| 5. |
- Kröll, Th, et al.
(författare)
-
Quadrupole Collectivity of neutron-rich nuclei around 132Sn
- 2008
-
Ingår i: Frontiers in Nuclear Structure, Astrophysics, and Reactions, FINUSTAR 2007. - : AIP. - 9780735405325 ; 1012, s. 296-299
-
Konferensbidrag (refereegranskat)abstract
- We report on the "safe" Coulomb excitation of neutron-rich Cd, Xe, and Ba isotopes in the vicinity of the doubly-magic nucleus 132Sn. The radioactive nuclei have been produced by ISOLDE at CERN and postaccelerated by the REX-ISOLDE facility. The γ-decay of excited states has been detected by the MINIBALL array. The presented preliminary results for the B(E2) values are consistent with expectations from phenomenological systematics and will be compared with theoretical calculations.
|
|
| 6. |
- Stefanescu, I., et al.
(författare)
-
Coulomb Excitation of 68,70Cu: First Use of Postaccelerated Isomeric Beams
- 2007
-
Ingår i: Physical Review Letters. ; 98
-
Tidskriftsartikel (refereegranskat)abstract
- We report on the first low-energy Coulomb excitation measurements with radioactive Ipi=6- beams of odd-odd nuclei 68,70Cu. The beams were produced at ISOLDE, CERN and were post-accelerated by REX-ISOLDE to 2.83 MeV/nucleon. gamma rays were detected with the MINIBALL spectrometer. The 6- beam was used to study the multiplet of states (3-, 4-, 5-, 6-) arising from the pi2p3/2nu1g9/2 configuration. The 4- state of the multiplet was populated via Coulomb excitation and the B(E2;6--->4-) value was determined in both nuclei. The results obtained illustrate the fragile stability of the Z=28 shell and N=40 subshell closures. A comparison with large-scale shell-model calculations using the 56Ni core shows the importance of the proton excitations across the Z=28 shell gap to the understanding of the nuclear structure in the neutron-rich nuclei with N[approximate]40.
|
|
| 7. |
- Cederkäll, Joakim, et al.
(författare)
-
REX-ISOLDE - experiences from the first year of operation
- 2004
-
Ingår i: Nuclear Physics A. - : Elsevier BV. - 0375-9474. ; 746, s. 17-17
-
Konferensbidrag (refereegranskat)abstract
- The Radioactive beam EXperiment (REX) at CERN-ISOLDE has been commissioned and the first experiments successfully completed during 2002 and 2003. The concept used for post-acceleration has proven to be flexible and the experimental program has therefore been extended during the past year. This paper relays some experiences drawn from using the machine in the current program and also conveys some plans for the future.
|
|
| 8. |
- Cederkäll, Joakim, et al.
(författare)
-
Sub-Barrier Coulomb Excitation of ^110Sn and Its Implications for the ^100Sn Shell Closure
- 2007
-
Ingår i: Physical Review Letters. - 1079-7114. ; 98:17, s. 172501-
-
Tidskriftsartikel (refereegranskat)abstract
- The first excited 2+ state of the unstable isotope 110Sn has been studied in safe Coulomb excitation at 2.82 MeV/u using the MINIBALL array at the REX-ISOLDE post accelerator at CERN. This is the first measurement of the reduced transition probability of this state using this method for a neutron deficient Sn isotope. The strength of the approach lies in the excellent peak-to-background ratio that is achieved. The extracted reduced transition probability, B(E2:0+-->2+)=0.220±0.022e2b2, strengthens the observation of the evolution of the B(E2) values of neutron deficient Sn isotopes that was observed recently in intermediate-energy Coulomb excitation of 108Sn. It implies that the trend of these reduced transition probabilities in the even-even Sn isotopes is not symmetric with respect to the midshell mass number A=116 as 100Sn is approached.
|
|
| 9. |
- Niedermaier, O., et al.
(författare)
-
"Safe" Coulomb excitation of Mg-30
- 2005
-
Ingår i: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 94:17, s. 172501 (artno)-
-
Tidskriftsartikel (refereegranskat)abstract
- We report on the first radioactive beam experiment performed at the recently commissioned REX-ISOLDE facility at CERN in conjunction with the highly efficient γ spectrometer MINIBALL. Using Mg-30 ions accelerated to an energy of 2.25 MeV/u together with a thin Ni-nat target, Coulomb excitation of the first excited 2(+) states of the projectile and target nuclei well below the Coulomb barrier was observed. From the measured relative deexcitation γ-ray yields the B(E2;0(gs)(+)→ 2(1)(+)) value of Mg-30 was determined to be 241(31)e(2) fm(4). Our result is lower than values obtained at projectile fragmentation facilities using the intermediate-energy Coulomb excitation method, and confirms the theoretical conjecture that the neutron-rich magnesium isotope Mg-30 resides outside the "island of inversion."
|
|
| 10. |
- Niedermaier, O., et al.
(författare)
-
The neutron-rich Mg isotopes: first results from MINIBALL at REX-ISOLDE
- 2005
-
Ingår i: Nuclear Physics A. - : Elsevier BV. - 0375-9474. ; 752, s. 273-273
-
Tidskriftsartikel (refereegranskat)abstract
- We report on the first radioactive beam experiment performed at the recently commissioned REX-ISOLDE facility at CERN in conjunction with the highly efficient γ spectrometer MINIBALL. Using Mg-30 ions accelerated to an energy of 2.25 MeV/u together with a thin Ni-nat target, Coulomb excitation of the first excited 2(+) states of the projectile and target nuclei well below the Coulomb barrier was observed. From the measured relative deexcitation γ-ray yields the B(E2;0(gs)(+)→ 2(1)(+)) value of Mg-30 was determined to be 241(31)e(2) fm(4). Our result is lower than values obtained at projectile fragmentation facilities using the intermediate-energy Coulomb excitation method, and confirms the theoretical conjecture that the neutron-rich magnesium isotope Mg-30 resides outside the "island of inversion."
|
|
