| 161. |
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| 162. |
- Nilsson, Thomas, 1965
(författare)
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European RIB facilities - status and future
- 2013
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Ingår i: Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms. - : Elsevier BV. - 0168-583X. ; 317:PART B, s. 194-200
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Tidskriftsartikel (refereegranskat)abstract
- The European landscape of Radioactive Ion Beam facilities is currently in a transformation phase. Several existing installations are undergoing extensive upgrade programmes while construction of next-generation facilities are underway. This encompasses facilities based on both the in-flight and the ISOL techniques, though such traditional scopes are being modified by developments concerning beam handling and preparation. The facility developments are a consequence of the strong scientific potential demonstrated by experiments with radioactive ion beams in the last decades. This potential was recently highlighted in the European roadmap for Nuclear Physics, coordinated by the Nuclear Physics European Collaboration Committee (NuPECC). A brief account of the main current facilities is made, including key instrumentation and future plans. The two major RIB facilities that are under construction in Europe, namely the NUSTAR part of FAIR (Facility for Antiproton and Ion Research) and SPIRAL2 at GANIL, are described. An outlook and roadmap for European ISOL-research according to the NuPECC long range plan, ultimately leading to the future EURISOL facility, is presented.
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| 163. |
- Nilsson, Thomas, 1965
(författare)
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Excursions Along the Drip Line
- 1995
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The drip lines are the outer boundaries of the chart of the nuclides, terminating the isobaric chains on both sides of the valley of .beta.-stability with respect to stability against particle emission. The neutron drip line is, at the moment, only experimentally accessible for the very lightest elements. When approaching the neutron drip line, the structure of the nuclei starts to show anomalies compared to stable nuclei. The best known case is 11Li, having an extremely dilute structure with two loosely bound neutrons surrounding a 9Li core with normal density. This kind of configuration has been labelled a neutron halo and can be found in several nuclei along the drip line. This work regards experimental studies of drip-line nuclei through dissociation reactions at high beam energies and spectroscopy of .beta.-delayed particles. The effect of cross-talk between neutron detectors has been measured and compared to the results of a simulation code. The measurements confirmed the validity of the code and showed a negligible contribution of cross-talk for the neutron-detector arrays used in experiments at GANIL. The .beta.-delayed charged particles following the precursors 6,8He have been studied at ISOLDE, CERN with a newly developed gas-detector telescope. The branching ratios for .beta.-delayed deuteron emission from 6He and .beta.-delayed triton emission from 8He were measured with improved accuracy and decreased low-energy cut-off compared to earlier experiments. In an experiment at GSI, dissociation of 8He, 11Li and 11Be, with energies of 240 MeV/u, 280 MeV/u and 460 MeV/u respectively, was studied. From the experimental data, cross sections and momentum distributions could be extracted. The reaction mechanisms could be probed by studying various reaction channels, revealing an invariability regarding the width of the neutron momentum distribution when concentrating upon the core-breakup reactions. The role of the unbound resonance 10Li has been elucidated by population through one-neutron stripping from 11Li and one-proton stripping from 11Be. The longitudinal and transverse momentum distributions from the reaction 11Li -> 9Li + X have been measured at the same beam energy. The widths were found to be identical, and the lack of Coulomb broadening in the transverse case indicates that the halo-removal reactions predominantly take place at large impact parameters.
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| 164. |
- Nilsson, Thomas, 1965, et al.
(författare)
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Halo-nuclei at ISOLDE
- 2000
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Ingår i: Hyperfine Interactions. - 0304-3843 .- 1572-9540. ; 129:1-4, s. 67-81
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Tidskriftsartikel (refereegranskat)abstract
- Nuclear halo states are studied experimentally with a wide range of techniques. We review the results coming from ISOLDE, emphasizing the beta -decay experiments. Some general comments on the role of beta -decays for halo research are given. We outline the possibilities for low-energy reaction experiments arising from REX-ISOLDE.
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| 165. |
- Nilsson, Thomas, 1965, et al.
(författare)
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He-6 and neutron momentum distributions from He-8 in nuclear break-up reactions at 240 MeV/u
- 1996
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Ingår i: Nuclear Physics A. - 0375-9474. ; 598:3, s. 418-434
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Tidskriftsartikel (refereegranskat)abstract
- Neutron and He-6 momentum distributions from He-8 break-up reactions in a C target have been measured at 240 MeV/u. The two-neutron removal cross section was found to be sigma(-2n) = 0.27 +/- 0.03 b. The nature of the momentum distributions is interpreted in some simple reaction scenarios.
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| 166. |
- Nilsson, Thomas, 1965, et al.
(författare)
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Muonic radioactive atoms - a unique probe for nuclear structure
- 2004
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Ingår i: Nuclear Physics A. - : Elsevier BV. - 0375-9474. ; 746, s. 513C-517C
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Konferensbidrag (refereegranskat)abstract
- Muonic atoms have been a source of high-precision experimental nuclear structure data for decades, through muonic X-rays that yield information on nuclear charge distributions. The intense driver beams for production of radioactive beams in so-called second generation facilities will simultaneously be capable of producing unprecedented amounts of low-energy muons. This paper concerns some of the potential synergies of combining unions with radioactive nuclei. as one possible new tool to be used at future RIB facilities. As a case study, muonic capture rates into highly excited states in Ni-78 have been calculated.
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| 167. |
- Nilsson, Thomas, 1965, et al.
(författare)
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Neutron Momentum Distributions from Core Break-up Reactions of Halo Nuclei
- 1995
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Ingår i: Europhysics Letters. - 0295-5075 .- 1286-4854. ; 30:1, s. 19-24
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Tidskriftsartikel (refereegranskat)abstract
- Neutron angular distributions from violent break-up reactions of Li-11 and Be-11 have been measured at 28 MeV/u and 280 MeV/u and at 41 MeV/u and 460 MeV/u, respectively. The derived neutron momentum distributions show a narrow component in transverse momentum that is within uncertainties independent of beam energy and target charge. This component is suggested to be simply related to the momentum distribution of the loosely bound halo neutron(s) in the projectiles.
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| 168. |
- Nilsson, Thomas, 1965
(författare)
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Nuclear Few-Body Physics at FAIR
- 2011
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Ingår i: Few-Body Systems. - : Springer Science and Business Media LLC. - 1432-5411 .- 0177-7963. ; 50:1-4, s. 121-127
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Konferensbidrag (refereegranskat)abstract
- The FAIR facility, to be constructed at the GSI site in Darmstadt, will be addressing a wealth of outstanding questions within the realm of subatomic, atomic and plasma physics through a combination of novel accelerators, storage rings and innovative experimental set-ups. One of the key installations is the fragment separator Super-FRS that will be able to deliver an unprecedented range of radioactive ion beams (RIBs) in the energy range of 0-1.5 GeV/u to the envisaged experiments collected within the NuSTAR collaboration. This will in particular permit new experimental investigations of nuclear few-body systems at extreme isospins, also reaching beyond the drip-lines, using the NuSTAR-(RB)-B-3 set-up. The outcome of pilot experiments on unbound systems are reported, as well as crucial detector upgrades.
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| 169. |
- Nilsson, Thomas, 1965
(författare)
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Nuclear reactions with radioactive beams at FAIR
- 2010
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Ingår i: Conference proceedings, Italian Physical Society. - 9788874380541 ; 101, s. 103-112
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Konferensbidrag (refereegranskat)abstract
- The future FAIR facility will be a world-leading infrastructure within many fields of contemporary physics. In particular, it will open up an unprecedented range of exotic nuclear beams in the energy interval between 0 - 1.5 GeV/u produced by the Super-FRS. These beams form the basis for the envisaged experimental programme being prepared within the NuSTAR collaboration that will cover most aspects of contemporary physics within nuclear structure, astrophysics and reactions. Nuclear reactions with relativistic radioactive beams is the specific field of study for the R3B project, building upon the existing ALADIN-LAND programme. A few examples of physics cases attainable at R3B and its precursor are given, as well as an overview of the ongoing detector upgrades.
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| 170. |
- Nilsson, Thomas, 1965
(författare)
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Radioactive ion beams at FAIR-NuSTAR
- 2008
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Ingår i: European Physical Journal: Special Topics. - : Springer Science and Business Media LLC. - 1951-6401 .- 1951-6355. ; 156:1, s. 1-12
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Tidskriftsartikel (refereegranskat)abstract
- The future FAIR facility will open up an unprecedented range of exotic nuclear beams in the energy interval between 0-1.5GeV/u produced by the Super-FRS. The envisaged experimental programme with radioactive beams, being prepared within the NuSTAR collaboration, will cover most aspects of contemporary physics within nuclear structure, astrophysics and reactions. An overview of this programme is given, with emphasis on high-energy reactions.
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