| 1. |
- Düllmann, Ch. E., et al.
(författare)
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Production and Decay of Element 114: High Cross Sections and the New Nucleus 277Hs
- 2010
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Ingår i: Physical Review Letters. - 1079-7114. ; 104:25
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Tidskriftsartikel (refereegranskat)abstract
- The fusion-evaporation reaction 244Pu(48Ca, 3-4n)288,289114 was studied at the new gas-filled recoil separator TASCA. Thirteen correlated decay chains were observed and assigned to the production and decay of 288,289114. At a compound nucleus excitation energy of E* = 39.8-43.9 MeV, the 4n evaporation channel cross section was 9.8(-3.1)(+3.9) pb. At E* = 36.1-39.5 MeV, that of the 3n evaporation channel was 8.0-(+7.4)(4.5) pb. In one of the 3n evaporation channel decay chains, a previously unobserved alpha branch in 281Ds was observed ( probability to be of random origin from background: 0.1%). This alpha decay populated the new nucleus 277Hs, which decayed by spontaneous fission after a lifetime of 4.5 ms.
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| 2. |
- Gates, J. M., et al.
(författare)
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First Superheavy Element Experiments at the GSI Recoil Separator TASCA: The Production and Decay of Element 114 in the 244Pu(48Ca,3-4n) Reaction
- 2011
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 83:5
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Tidskriftsartikel (refereegranskat)abstract
- Experiments with the new recoil separator, Transactinide Separator and Chemistry Apparatus (TASCA), at the GSI were performed by using beams of Ca-48 to irradiate targets of Pb206-208, which led to the production of No252-254 isotopes. These studies allowed for evaluation of the performance of TASCA when coupled to a new detector and electronics system. By following these studies, the isotopes of element 114 ((288-291)114) were produced in irradiations of Pu-244 targets with Ca-48 beams at compound nucleus excitation energies around 41.7 and 37.5 MeV, demonstrating TASCA's ability to perform experiments with picobarn-level cross sections. A total of 15 decay chains were observed and were assigned to the decay of 288-291114. A new a-decay branch in (281)Ds was observed, leading to the new nucleus (277)Hs.
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| 3. |
- Yakushev, A., et al.
(författare)
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Superheavy Element Flerovium (Element 114) Is a Volatile Metal
- 2014
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Ingår i: Inorganic Chemistry. - : American Chemical Society (ACS). - 1520-510X .- 0020-1669. ; 53:3, s. 1624-1629
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Tidskriftsartikel (refereegranskat)abstract
- The electronic structure of superheavy elements (Z ≥ 104) and their chemical properties are dominated by relativistic effects. Recently two superheavy elements were recognized by the IUPAC and named flerovium (Fl, Z = 114) and livermorium (Lv, Z = 116). Fl is the heaviest element with which chemical experiments were performed. Here, we report on experiments that help answering the long-standing question whether Fl behaves rather like a noble gas or like a metal.
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| 4. |
- Andersson, L-L, et al.
(författare)
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TASISpec - A Highly Efficient Multi-coincidence Spectrometer for Nuclear Structure Investigations of the Heaviest Nuclei
- 2010
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - : Elsevier BV. - 0167-5087 .- 0168-9002. ; 622:1, s. 164-170
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Tidskriftsartikel (refereegranskat)abstract
- TASISpec (TASCA in Small Image mode Spectroscopy) combines composite Ge- and Si-detectors for a new detector setup aimed towards multi-coincidence gamma -ray, X-ray, conversion electron, fission fragment, and a-particle spectroscopy of the heaviest nuclei. It exploits the TASCA separator's unique small image focal mode, i.e. the fact that evaporation residues produced in fusion-evaporation reactions can be focused into an area of less than 3 cm in diameter. This provides the possibility to pack detectors in very close geometry, resulting in an unprecedented detection efficiency of radioactive decays in prompt and delayed coincidence with implanted nuclei. Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved.
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| 5. |
- Khuyagbaatar, J., et al.
(författare)
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Study of the Average Charge States of 188Pb and 252,254No Ions at the Gas-filled Separator TASCA
- 2012
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - : Elsevier BV. - 0167-5087 .- 0168-9002. ; 689, s. 40-46
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Tidskriftsartikel (refereegranskat)abstract
- The average charge states of Pb-188 and No-252,No-254 ions in dilute helium gas were measured at the gas-filled recoil separator TASCA. Hydrogen gas was also used as a filling gas for measurements of the average charge state of No-254. Helium and hydrogen gases at pressures from 0.2 mbar to 2.0 mbar were used. A strong dependence of the average charge state on the pressure of the filling gases was observed for both, helium and hydrogen. The influence of this dependence, classically attributed to the so-called "density effect", on the performance of TASCA was investigated. The average charge states of No-254 ions were also measured in mixtures of helium and hydrogen gases at low gas pressures around 1.0 mbar. From the experimental results simple expressions for the prediction of average charge states of heavy ions moving in rarefied helium gas, hydrogen gas, and in their mixture were derived. (C) 2012 Elsevier B.V. All rights reserved.
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| 10. |
- Maguire Jr., Gerald Q., et al.
(författare)
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A Digital Radiology Department
- 1982
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Ingår i: Medical physics (Lancaster). - 0094-2405. ; 9:4, s. 636-
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Tidskriftsartikel (refereegranskat)
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