| 1. |
- Ponnath, L., et al.
(författare)
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Measurement of nuclear interaction cross sections towards neutron-skin thickness determination
- 2024
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Ingår i: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - 0370-2693. ; 855
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Tidskriftsartikel (refereegranskat)abstract
- The accuracy of reaction theories used to extract properties of exotic nuclei from scattering experiments is often unknown or not quantified, but of utmost importance when, e.g., constraining the equation of state of asymmetric nuclear matter from observables as the neutron-skin thickness. In order to test the Glauber multiple-scattering model, the total interaction cross section of [Formula presented] on carbon targets was measured at initial beam energies of 400, 550, 650, 800, and 1000 MeV/nucleon. The measurements were performed during the first experiment of the newly constructed R3B (Reaction with Relativistic Radioactive Beams) experiment after the start of FAIR Phase-0 at the GSI/FAIR facility with beam energies of 400, 550, 650, 800, and 1000 MeV/nucleon. The combination of the large-acceptance dipole magnet GLAD and a newly designed and highly efficient Time-of-Flight detector enabled a precise transmission measurement with several target thicknesses for each initial beam energy with an experimental uncertainty of ±0.4%. A comparison with the Glauber model revealed a discrepancy of around 3.1% at higher beam energies, which will serve as a crucial baseline for the model-dependent uncertainty in future fragmentation experiments.
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| 2. |
- Elekes, Z., et al.
(författare)
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Shape coexistence in 66Se
- 2023
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Ingår i: Physics Letters B. - : Elsevier. - 0370-2693 .- 1873-2445. ; 844
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Tidskriftsartikel (refereegranskat)abstract
- The nuclear structure of 66Se, nucleus beyond the N=Z line on the proton-rich side of the valley of stability, was investigated by the neutron knock-out reaction 67Se(12C,X)66Se using a 12C target. The analysis of the singles spectrum of the γ-rays emitted during the de-excitation of the populated low-lying excited states revealed two previously detected (927(4) keV, 1460(32) keV) and three new (744(6) keV, 1210(17) keV, 1661(23) keV) transitions. The 744-keV, the 1210-keV, and the 1460-keV transitions were found to be in coincidence with the one at 927 keV. The spectrum coincident with the 927-keV transition showed a further possible transition at 299(35) keV, which was obscured by significant atomic background in the singles spectrum. This transition might correspond to a peak previously reported at 273(5) keV that could not be assigned to 66Se unambiguously. Based on a comparison of the experimental data to theoretical calculations, four new excited states are proposed which suggest that 66Se exhibits shape coexistence.
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| 3. |
- Grigorenko, L. V., et al.
(författare)
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Complete correlation studies of two-proton decays: Be-6 and Fe-45
- 2009
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Ingår i: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 677:1-2, s. 30-35
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Tidskriftsartikel (refereegranskat)abstract
- The complete three-body correlation pictures are experimentally reconstructed for the two-proton decays of the Be-6 and (45)e ground states. We are able to see qualitative similarities and differences between these decays. They demonstrate very good agreement with the predictions of a theoretical three-body cluster model. Validity of the theoretical methods for treatment of the three-body Coulombic decays of this class is thus established by the broad range of lifetimes and nuclear masses spanned by these cases. Implementations for decay dynamics and nuclear structure of 2p emitters are discussed. (C) 2009 Elsevier B.V. All rights reserved.
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| 4. |
- Grigorenko, L. V., et al.
(författare)
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Three-body decay of Be-6
- 2009
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Ingår i: Physical Review C - Nuclear Physics. - 2469-9985 .- 2469-9993. ; 80:3
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Tidskriftsartikel (refereegranskat)abstract
- Three-body correlations for the ground-state decay of the lightest two-proton emitter Be-6 are studied both theoretically and experimentally. Theoretical studies are performed in a three-body hyperspherical-harmonics cluster model. In the experimental studies, the ground state of Be-6 was formed following the alpha decay of a C-10 beam inelastically excited through interactions with Be and C targets. Excellent agreement between theory and experiment is obtained demonstrating the existence of complicated correlation patterns that can elucidate the structure of Be-6 and, possibly, of the A = 6 isobars.
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| 5. |
- Bolelli, G., et al.
(författare)
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Sliding and abrasive wear behaviour of HVOF- and HVAF-sprayed Cr3C2-NiCr hardmetal coatings
- 2016
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Ingår i: Wear. - : Elsevier BV. - 0043-1648 .- 1873-2577. ; 358-359, s. 32-50
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Tidskriftsartikel (refereegranskat)abstract
- This paper provides a comprehensive characterisation of HVOF- and HVAF-sprayed Cr3C2–25 wt.% NiCr hardmetal coatings. One commercial powder composition with two different particle size distributions was processed using five HVOF and HVAF thermal spray systems.All coatings contain less Cr3C2 than the feedstock powder, possibly due to the rebound of some Cr3C2-rich particles during high-velocity impact onto the substrate.Dry sand-rubber wheel abrasive wear testing causes both grooving and pull-out of splat fragments. Mass losses depend on inter- and intra-lamellar cohesion, being higher (≥70 mg after a wear distance of 5904 m) for the coatings deposited with the coarser feedstock powder or with one type of HVAF torch.Sliding wear at room temperature against alumina involves shallower abrasive grooving, small-scale delamination and carbide pull-outs, and it is controlled by intra-lamellar cohesion. The coatings obtained from the fine feedstock powder exhibit the lowest wear rates (≈5x10−6 mm3/(Nm)). At 400 °C, abrasive grooving dominates the sliding wear behaviour; wear rates increase by one order of magnitude but friction coefficients decrease from ≈0.7 to ≈0.5. The thermal expansion coefficient of the coatings (11.08x10−6 °C−1 in the 30–400 °C range) is sufficiently close to that of the steel substrate (14.23x10−6 °C−1) to avoid macro-cracking
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| 6. |
- Bolelli, G., et al.
(författare)
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Tribology of HVOF- and HVAF-sprayed WC-10Co4Cr hardmetal coatings : A comparative assessment
- 2015
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Ingår i: Surface and Coatings Technology. - : Elsevier. - 0257-8972. ; 265, s. 125-144
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Tidskriftsartikel (refereegranskat)abstract
- his paper provides a comprehensive assessment of the sliding and abrasive wear behaviour of WC–10Co4Cr hardmetal coatings, representative of the existing state-of-the-art. A commercial feedstock powder with two different particle size distributions was sprayed onto carbon steel substrates using two HVOF and two HVAF spray processes.Mild wear rates of < 10-7 mm3/(Nm) and friction coefficients of ≈ 0.5 were obtained for all samples in ball-on-disk sliding wear tests at room temperature against Al2O3 counterparts. WC–10Co4Cr coatings definitely outperform a reference electrolytic hard chromium coating under these test conditions. Their wear mechanisms include extrusion and removal of the binder matrix, with the formation of a wavy surface morphology, and brittle cracking. The balance of such phenomena is closely related to intra-lamellar features, and rather independent of those properties (e.g. indentation fracture toughness, elastic modulus) which mainly reflect large-scale inter-lamellar cohesion, as quantitatively confirmed by a principal component analysis. Intra-lamellar dissolution of WC into the matrix indeed increases the incidence of brittle cracking, resulting in slightly higher wear rates. At 400 °C, some of the hardmetal coatings fail because of the superposition between tensile residual stresses and thermal expansion mismatch stresses (due to the difference between the thermal expansion coefficients of the steel substrate and of the hardmetal coating). Those which do not fail, on account of lower residual stresses, exhibit higher wear rates than at room temperature, due to oxidation of the WC grains.The resistance of the coatings against abrasive wear, assessed by dry sand–rubber wheel testing, is related to inter-lamellar cohesion, as proven by a principal component analysis of the collected dataset. Therefore, coatings deposited from coarse feedstock powders suffer higher wear loss than those obtained from fine powders, as brittle inter-lamellar detachment is caused by their weaker interparticle cohesion, witnessed by their systematically lower fracture toughness as well.
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| 7. |
- Iacob, VE, et al.
(författare)
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Reflection asymmetric states in Nd-146
- 1996
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Ingår i: NUCLEAR PHYSICS A. - : ELSEVIER SCIENCE BV. ; 596:1, s. 155-170
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- High-spin states in Nd-146 up to an excitation energy of 7.4 MeV were studied via the Xe-136(C-13,3n gamma) reaction. A quasi-rotational band consisting of alternating parity levels connected by fast El transitions is found, indicating strong octupole cor
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