| 1. |
- Fellinger, Joris, et al.
(författare)
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Tungsten based divertor development for Wendelstein 7-X
- 2023
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Ingår i: Nuclear Materials and Energy. - 2352-1791. ; 37
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Tidskriftsartikel (refereegranskat)abstract
- Wendelstein 7-X, the world’s largest superconducting stellarator in Greifswald (Germany), started plasma experiments with a water-cooled plasma-facing wall in 2022, allowing for long pulse operation. In parallel, a project was launched in 2021 to develop a W based divertor, replacing the current CFC divertor, to demonstrate plasma performance of a stellarator with a reactor relevant plasma facing materials with low tritium retention. The project consists of two tasks: Based on experience from the previous experimental campaigns and improved physics modelling, the geometry of the plasma-facing surface of the divertor and baffles is optimized to prevent overloads and to improve exhaust. In parallel, the manufacturing technology for a W based target module is qualified. This paper gives a status update of project. It focusses on the conceptual design of a W based target module, the manufacturing technology and its qualification, which is conducted in the framework of the EUROfusion funded WPDIV program. A flat tile design in which a target module is made of a single target element is pursued. The technology must allow for moderate curvatures of the plasma-facing surface to follow the magnetic field lines. The target element is designed for steady state heat loads of 10 MW/m2 (as for the CFC divertor). Target modules of a similar size and weight as for the CFC divertor are assumed (approx. < 0.25 m2 and < 60 kg) using the existing water cooling infrastructure providing 5 l/s and roughly maximum 15 bar pressure drop per module. The main technology under qualification is based on a CuCrZr heat sink made either by additive manufacturing using laser powder bed fusion (LPBF) or by uniaxial diffusion welding of pre-machined forged CuCrZr plates. After heat treatment, the plasma-facing side of the heat sink is covered by W or if feasible by the more ductile WNiFe, preferably by coating or alternatively by hot isostatic pressing W based tiles with a soft OFE-Cu interlayer. Last step is a final machining of the plasma-exposed surface and the interfaces to the water supply lines and supports to correct manufacturing deformations.
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| 2. |
- Ilieva, S., et al.
(författare)
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Coulomb excitation of neutron-rich Cd isotopes
- 2014
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 89:1
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Tidskriftsartikel (refereegranskat)abstract
- The isotopes (122),(124),Cd-126 were studied in a "safe" Coulomb-excitation experiment at the radioactive ion-beam facility REX-ISOLDE at CERN. The reduced transition probabilities B(E2; 0(g. s)(vertical bar) -> 2(1)(+)) and limits for the quadrupole moments of the first 2(+) excited states in the three isotopes were determined. The onset of collectivity in the vicinity of the Z = 50 and N = 82 shell closures is discussed by comparison with shell model and beyond mean-field calculations.
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| 3. |
- Kroell, Th., et al.
(författare)
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Coulomb excitation of neutron-rich (138,140,142) Xe at REX-ISOLDE
- 2007
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Ingår i: The European Physical Journal. Special Topics. - : Springer Science and Business Media LLC. - 1951-6355 .- 1951-6401. ; 150, s. 127-129
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Tidskriftsartikel (refereegranskat)abstract
- We report on "safe" Coulomb excitation of neutron-rich (138,140,142) Xe nuclei. The radioactive nuclei have been produced by ISOLDE at CERN and post-accelerated by the REX-ISOLDE facility. The gamma-rays emitted by the decay of excited states have been detected by the MINIBALL array. Recent results are presented.
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| 4. |
- Kröll, Th, et al.
(författare)
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Quadrupole Collectivity of neutron-rich nuclei around 132Sn
- 2008
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Ingår i: Frontiers in Nuclear Structure, Astrophysics, and Reactions, FINUSTAR 2007. - : AIP. - 9780735405325 ; 1012, s. 296-299
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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.
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| 5. |
- Stefanescu, I., et al.
(författare)
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Coulomb Excitation of 68,70Cu: First Use of Postaccelerated Isomeric Beams
- 2007
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Ingår i: Physical Review Letters. ; 98
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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.
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| 6. |
- Aad, G, et al.
(författare)
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- 2015
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swepub:Mat__t
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