| 1. |
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Overview of the JET results
- 2015
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 55:10
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Tidskriftsartikel (refereegranskat)
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| 2. |
- Bezbakh, A.A., et al.
(författare)
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Evidence for the First Excited State of H 7
- 2020
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Ingår i: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 124:2
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Tidskriftsartikel (refereegranskat)abstract
- The H7 system was populated in the H2(He8,He3)H7 reaction with a 26 AMeV He8 beam. The H7 missing mass energy spectrum, the H3 energy and angular distributions in the H7 decay frame were reconstructed. The H7 missing mass spectrum shows a peak, which can be interpreted either as unresolved 5/2+ and 3/2+ doublet or one of these states at 6.5(5) MeV. The data also provide indications of the 1/2+ ground state of H7 located at 1.8(5) MeV with quite a low population cross section of ∼25 μb/sr within angular range θc.m.≃(17°-27°).
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| 3. |
- Muzalevskii, I. A., et al.
(författare)
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Resonant states in H 7: Experimental studies of the H 2 (He 8, He 3) reaction
- 2021
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Ingår i: Physical Review C. - 2469-9985 .- 2469-9993. ; 103:4
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Tidskriftsartikel (refereegranskat)abstract
- The extremely neutron-rich system H7 was studied in the direct H2(He8,He3)H7 transfer reaction with a 26 AMeV secondary He8 beam [Bezbakh et al., Phys. Rev. Lett. 124, 022502 (2020)PRLTAO0031-900710.1103/PhysRevLett.124.022502]. The missing mass spectrum and center-of-mass angular distributions of H7, as well as the momentum distribution of the H3 fragment in the H7 frame, were constructed. In addition, we carried out another experiment with the same beam but a modified setup, which was cross-checked by the study of the H2(Be10,He3)Li9 reaction. A solid experimental evidence is provided that two resonant states of H7 are located in its spectrum at 2.2(5) and 5.5(3)MeV relative to the H3+4n decay threshold. Also, there are indications that the resonant states at 7.5(3) and 11.0(3)MeV are present in the measured H7 spectrum. Based on the energy and angular distributions, obtained for the studied H2(He8,He3)H7 reaction, the weakly populated 2.2(5)-MeV peak is ascribed to the H7 ground state. It is highly plausible that the firmly ascertained 5.5(3)-MeV state is the 5/2+ member of the H7 excitation 5/2+-3/2+ doublet, built on the 2+ configuration of valence neutrons. The supposed 7.5-MeV state can be another member of this doublet, which could not be resolved in Bezbakh et al. [Phys. Rev. Lett. 124, 022502 (2020)PRLTAO0031-900710.1103/PhysRevLett.124.022502]. Consequently, the two doublet members appeared in the spectrum of H7 in the work mentioned above as a single broad 6.5-MeV peak.
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| 4. |
- Nikolskii, E.Y., et al.
(författare)
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H 6 states studied in the H 2 (He 8, He 4) reaction and evidence of an extremely correlated character of the H 5 ground state
- 2022
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Ingår i: Physical Review C. - 2469-9993 .- 2469-9985. ; 105:6
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Tidskriftsartikel (refereegranskat)abstract
- The extremely neutron-rich system H6 was studied in the direct H2(He8,He4)H6 transfer reaction with a 26A MeV secondary He8 beam. The measured missing mass spectrum shows a broad bump at ≈4-8 MeV above the H3+3n decay threshold. This bump can be interpreted as a broad resonant state in H6 at 6.8(5) MeV. The population cross section of such a presumably p-wave state (or it may be few overlapping states) in the energy range from 4 to 8 MeV is dσ/dωc.m.≃190-80+40μb/sr in the angular range 5°<θc.m.<16°. The obtained missing mass spectrum is practically free of H6 events below 3.5 MeV (dσ/dωc.m. 5μb/sr in the same angular range). The steep rise of the H6 missing mass spectrum at ≈3 MeV allows us to derive the lower limit for the possible resonant-state energy in H6 to be 4.5(3) MeV. According to the paring energy estimates, such a 4.5(3) MeV resonance is a realistic candidate for the H6 ground state (g.s.). The obtained results confirm that the decay mechanism of the H7 g.s. (located at 2.2 MeV above the H3+4n threshold) is the "true"(or simultaneous) 4n emission. The resonance energy profiles and the momentum distributions of fragments of the sequential H6→H5(g.s.)+n→H3+3n decay were analyzed by the theoretically updated direct four-body-decay and sequential-emission mechanisms. The measured momentum distributions of the H3 fragments in the H6 rest frame indicate very strong "dineutron-type"correlations in the H5 ground state decay.
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| 5. |
- Nikolskii, E.Y., et al.
(författare)
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Study of proton and deuteron pickup reactions (d, 3 He), (d, 4 He) with 8 He and 10 Be radioactive beams at ACCULINNA-2 fragment separator
- 2023
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Ingår i: Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms. - 0168-583X. ; 541, s. 121-125
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Tidskriftsartikel (refereegranskat)abstract
- The extremely neutron-rich systems 7H, 6H were studied in the 2H(8He, 3He)7H and 2H(8He, 4He)6H proton and deuteron pickup reactions with a 26 AMeV secondary 8He beam produced at the new ACCULINNA-2 fragment separator. In addition, the same proton and deuteron pickup reactions were generated using the 42 AMeV 10Be beam, and the population of low-lying 9Li and 8Li states was measured in reactions 2H(10Be,3He)9Li and 2H(10Be,4He)8Li, respectively. The latter were used as reference measurements in order to check the setup calibration over the excitation energy of 7,6H and to determine the real experimental energy resolution which was compared with Monte Carlo calculations. The corresponding results obtained for the superheavy hydrogen systems 7H, 6H are presented and discussed. Typical excitation spectra of the 9Li and 8Li nuclei are also shown.
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| 6. |
- Torregrosa-Martin, C., et al.
(författare)
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Overview of IFMIF-DONES diagnostics : Requirements and techniques
- 2023
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Ingår i: Fusion engineering and design. - : Elsevier. - 0920-3796 .- 1873-7196. ; 191
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Tidskriftsartikel (refereegranskat)abstract
- The IFMIF-DONES Facility is a unique first-class scientific infrastructure whose construction is foreseen in Granada, Spain, in the coming years. Strong integration efforts are being made at the current project phase aiming at harmonizing the ongoing design of the different and complex Systems of the facility. The consolidation of the Diagnostics and Instrumentation, transversal across many of them, is a key element of this purpose. A top-down strategy is proposed for a systematic Diagnostics Review and Requirement definition, putting emphasis in the one-of-a-kind instruments necessary by the operational particularities of some of the Systems, as well as to the harsh environment that they shall survive. In addition, other transversal aspects such as the ones related to Safety and Machine Protection and their respective requirements shall be also considered. The goal is therefore to advance further and solidly in the respective designs, identify problems in advance, and steer the Diagnostics development and validation campaigns that will be required. The present work provides an overview of this integration strategy as well as a description of some of the most challenging Diagnostics and Instruments within the facility, including several proposed techniques currently under study.
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| 7. |
- Allentoft, Morten E., et al.
(författare)
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Population genomics of post-glacial western Eurasia
- 2024
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Ingår i: Nature. - 0028-0836 .- 1476-4687. ; 625:7994, s. 301-311
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Tidskriftsartikel (refereegranskat)abstract
- Western Eurasia witnessed several large-scale human migrations during the Holocene1–5. Here, to investigate the cross-continental effects of these migrations, we shotgun-sequenced 317 genomes—mainly from the Mesolithic and Neolithic periods—from across northern and western Eurasia. These were imputed alongside published data to obtain diploid genotypes from more than 1,600 ancient humans. Our analyses revealed a ‘great divide’ genomic boundary extending from the Black Sea to the Baltic. Mesolithic hunter-gatherers were highly genetically differentiated east and west of this zone, and the effect of the neolithization was equally disparate. Large-scale ancestry shifts occurred in the west as farming was introduced, including near-total replacement of hunter-gatherers in many areas, whereas no substantial ancestry shifts happened east of the zone during the same period. Similarly, relatedness decreased in the west from the Neolithic transition onwards, whereas, east of the Urals, relatedness remained high until around 4,000 bp, consistent with the persistence of localized groups of hunter-gatherers. The boundary dissolved when Yamnaya-related ancestry spread across western Eurasia around 5,000 bp, resulting in a second major turnover that reached most parts of Europe within a 1,000-year span. The genetic origin and fate of the Yamnaya have remained elusive, but we show that hunter-gatherers from the Middle Don region contributed ancestry to them. Yamnaya groups later admixed with individuals associated with the Globular Amphora culture before expanding into Europe. Similar turnovers occurred in western Siberia, where we report new genomic data from a ‘Neolithic steppe’ cline spanning the Siberian forest steppe to Lake Baikal. These prehistoric migrations had profound and lasting effects on the genetic diversity of Eurasian populations.
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| 8. |
- Serikov, V. V., et al.
(författare)
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Formation of solid solutions of gallium in Fe-Cr and Fe-Co alloys : Mossbauer studies and first-principles calculations
- 2014
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Ingår i: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388 .- 1873-4669. ; 614, s. 297-304
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Tidskriftsartikel (refereegranskat)abstract
- Investigation of Ga influence on the structure of Fe-Cr and Fe-Co alloys was performed with the use of Mossbauer spectroscopy and X-ray diffraction methods. The experimental results are compared with results of first-principles calculations of the mixing and solubility energies for Ga in an Fe-X (X = Co, Cr) alloy both in ferromagnetic and paramagnetic states. It is shown that Ga mainly goes into the solid solutions of the base alloys. In the alloys of the Fe-Cr system, doping with Ga handicaps the decomposition of solid solutions, observed in the binary alloys, and increases its stability. In the alloys with Co, Ga also favors the uniformity of solid solutions. The results of the first-principles calculations testify in favor of a preferable dissolution of Ga in the FeCo regions of a multicomponent structure rather than FeCr regions, both types of regions being in the ferromagnetic state at the temperature of annealing. The analysis of Mossbauer experiments gives some grounds to conclude that if, owing to liquation, clusterization, or initial stages of phase separation, there exist regions enriched in iron, some amount of Ga atoms prefer to enter the nearest surroundings of iron atoms, thus forming binary Fe-Ga regions (or phases).
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| 9. |
- Axelsson, L., et al.
(författare)
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Study of the unbound nucleus 11N by elastic resonance scattering
- 1996
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813 .- 2469-9985 .- 2469-9993. ; 54:4, s. 1511-1514
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Tidskriftsartikel (refereegranskat)abstract
- Resonances in the unbound nucleus 11N have been studied, using the resonance scattering reaction 10C+p. The data give evidence for three states above the 10C+p threshold with energies 1.30, 2.04, and 3.72 MeV. These states can be interpreted, in a potential-model analysis, as the ground state and the first two excited states with spin-parity 1 / 2+, 1 / 2-, and 5 / 2+ arising from the shell-model orbitals 1s1 / 2, 0p1 / 2, and 0d5 / 2. A narrow state superposed on a broad structure found at higher energy could be interpreted as the mirror state of the 3 / 2- in 11Be shifted down in energy. This shift would suggest a large radius of the potential.
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| 10. |
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