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3.
  • Akkoyun, S., et al. (författare)
  • AGATA - Advanced GAmma Tracking Array
  • 2012
  • Ingår i: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. - : Elsevier BV. - 0168-9002 .- 0167-5087 .- 1872-9576. ; 668, s. 26-58
  • Tidskriftsartikel (refereegranskat)abstract
    • The Advanced GAmma Tracking Array (AGATA) is a European project to develop and operate the next generation γ-ray spectrometer. AGATA is based on the technique of γ-ray energy tracking in electrically segmented high-purity germanium crystals. This technique requires the accurate determination of the energy, time and position of every interaction as a γ ray deposits its energy within the detector volume. Reconstruction of the full interaction path results in a detector with very high efficiency and excellent spectral response. The realisation of γ-ray tracking and AGATA is a result of many technical advances. These include the development of encapsulated highly segmented germanium detectors assembled in a triple cluster detector cryostat, an electronics system with fast digital sampling and a data acquisition system to process the data at a high rate. The full characterisation of the crystals was measured and compared with detector- response simulations. This enabled pulse-shape analysis algorithms, to extract energy, time and position, to be employed. In addition, tracking algorithms for event reconstruction were developed. The first phase of AGATA is now complete and operational in its first physics campaign. In the future AGATA will be moved between laboratories in Europe and operated in a series of campaigns to take advantage of the different beams and facilities available to maximise its science output. The paper reviews all the achievements made in the AGATA project including all the necessary infrastructure to operate and support the spectrometer. © 2011 Elsevier B.V. All rights reserved.
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4.
  • Klionsky, Daniel J., et al. (författare)
  • Guidelines for the use and interpretation of assays for monitoring autophagy
  • 2012
  • Ingår i: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
  • Forskningsöversikt (refereegranskat)abstract
    • In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
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5.
  • Reifarth, R., et al. (författare)
  • Nuclear astrophysics with radioactive ions at FAIR
  • 2016
  • Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 665:1
  • Konferensbidrag (refereegranskat)abstract
    • The nucleosynthesis of elements beyond iron is dominated by neutron captures in the s and r processes. However, 32 stable, proton-rich isotopes cannot be formed during those processes, because they are shielded from the s-process flow and r-process beta-decay chains. These nuclei are attributed to the p and rp process. For all those processes, current research in nuclear astrophysics addresses the need for more precise reaction data involving radioactive isotopes. Depending on the particular reaction, direct or inverse kinematics, forward or time-reversed direction are investigated to determine or at least to constrain the desired reaction cross sections. The Facility for Antiproton and Ion Research (FAIR) will offer unique, unprecedented opportunities to investigate many of the important reactions. The high yield of radioactive isotopes, even far away from the valley of stability, allows the investigation of isotopes involved in processes as exotic as the r or rp processes.
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6.
  • Menden, MP, et al. (författare)
  • Community assessment to advance computational prediction of cancer drug combinations in a pharmacogenomic screen
  • 2019
  • Ingår i: Nature communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 10:1, s. 2674-
  • Tidskriftsartikel (refereegranskat)abstract
    • The effectiveness of most cancer targeted therapies is short-lived. Tumors often develop resistance that might be overcome with drug combinations. However, the number of possible combinations is vast, necessitating data-driven approaches to find optimal patient-specific treatments. Here we report AstraZeneca’s large drug combination dataset, consisting of 11,576 experiments from 910 combinations across 85 molecularly characterized cancer cell lines, and results of a DREAM Challenge to evaluate computational strategies for predicting synergistic drug pairs and biomarkers. 160 teams participated to provide a comprehensive methodological development and benchmarking. Winning methods incorporate prior knowledge of drug-target interactions. Synergy is predicted with an accuracy matching biological replicates for >60% of combinations. However, 20% of drug combinations are poorly predicted by all methods. Genomic rationale for synergy predictions are identified, including ADAM17 inhibitor antagonism when combined with PIK3CB/D inhibition contrasting to synergy when combined with other PI3K-pathway inhibitors in PIK3CA mutant cells.
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7.
  • Hudson, Lawrence N, et al. (författare)
  • The database of the PREDICTS (Projecting Responses of Ecological Diversity In Changing Terrestrial Systems) project
  • 2017
  • Ingår i: Ecology and Evolution. - : John Wiley & Sons. - 2045-7758. ; 7:1, s. 145-188
  • Tidskriftsartikel (refereegranskat)abstract
    • The PREDICTS project-Projecting Responses of Ecological Diversity In Changing Terrestrial Systems (www.predicts.org.uk)-has collated from published studies a large, reasonably representative database of comparable samples of biodiversity from multiple sites that differ in the nature or intensity of human impacts relating to land use. We have used this evidence base to develop global and regional statistical models of how local biodiversity responds to these measures. We describe and make freely available this 2016 release of the database, containing more than 3.2 million records sampled at over 26,000 locations and representing over 47,000 species. We outline how the database can help in answering a range of questions in ecology and conservation biology. To our knowledge, this is the largest and most geographically and taxonomically representative database of spatial comparisons of biodiversity that has been collated to date; it will be useful to researchers and international efforts wishing to model and understand the global status of biodiversity.
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8.
  • Lehr, C., et al. (författare)
  • Unveiling the two-proton halo character of 17 Ne: Exclusive measurement of quasi-free proton-knockout reactions
  • 2022
  • Ingår i: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 827
  • Tidskriftsartikel (refereegranskat)abstract
    • The proton drip-line nucleus 17Ne is investigated experimentally in order to determine its two-proton halo character. A fully exclusive measurement of the 17Ne(p,2p)16F→15⁎O+p quasi-free one-proton knockout reaction has been performed at GSI at around 500 MeV/nucleon beam energy. All particles resulting from the scattering process have been detected. The relevant reconstructed quantities are the angles of the two protons scattered in quasi-elastic kinematics, the decay of 16F into 15O (including γ decays from excited states) and a proton, as well as the 15O+p relative-energy spectrum and the 16F momentum distributions. The latter two quantities allow an independent and consistent determination of the fractions of l=0 and l=2 motion of the valence protons in 17Ne. With a resulting relatively small l=0 component of only around 35(3)%, it is concluded that 17Ne exhibits a rather modest halo character only. The quantitative agreement of the two values deduced from the energy spectrum and the momentum distributions supports the theoretical treatment of the calculation of momentum distributions after quasi-free knockout reactions at high energies by taking into account distortions based on the Glauber theory. Moreover, the experimental data allow the separation of valence-proton knockout and knockout from the 15O core. The latter process contributes with 11.8(3.1) mb around 40% to the total proton-knockout cross section of 30.3(2.3) mb, which explains previously reported contradicting conclusions derived from inclusive cross sections.
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9.
  • Marganiec, J., et al. (författare)
  • Coulomb breakup of 17Ne from the viewpoint of nuclear astrophysics
  • 2012
  • Ingår i: Proceedings of Science. - Proceedings of Science : Sissa. - 1824-8039.
  • Konferensbidrag (refereegranskat)abstract
    • By the Coulomb breakup of 17Ne, the time-reversed reaction 15O(2p,γ)17Ne has been studied. This reaction might play an important role in the rp process, as a break-out reaction of the hot CNO cycle. The secondary 17Ne ion beam with an energy of 500 MeV/nucleon has been dissociated in a Pb target. The reaction products have been detected with the LAND-R3B experimental setup at GSI. The preliminary differential and integral Coulomb dissociation cross section sCoul has been determined, which then will be converted into a photo-absorption cross section sphoto, and a two-proton radiative capture cross section σcap. Additionally, information about the structure of the 17Ne, a potential two-proton halo nucleus, will be received. The analysis is in progress. © Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence.
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10.
  • Wamers, F., et al. (författare)
  • Comparison of electromagnetic and nuclear dissociation of Ne 17
  • 2018
  • Ingår i: Physical Review C. - 2469-9985 .- 2469-9993. ; 97:3
  • Tidskriftsartikel (refereegranskat)abstract
    • The Borromean drip-line nucleus Ne17 has been suggested to possess a two-proton halo structure in its ground state. In the astrophysical rp-process, where the two-proton capture reaction O15(2p,γ)Ne17 plays an important role, the calculated reaction rate differs by several orders of magnitude between different theoretical approaches. To add to the understanding of the Ne17 structure we have studied nuclear and electromagnetic dissociation. A 500 MeV/u Ne17 beam was directed toward lead, carbon, and polyethylene targets. Oxygen isotopes in the final state were measured in coincidence with one or two protons. Different reaction branches in the dissociation of Ne17 were disentangled. The relative populations of s and d states in F16 were determined for light and heavy targets. The differential cross section for electromagnetic dissociation (EMD) shows a continuous internal energy spectrum in the three-body system O15+2p. The Ne17 EMD data were compared to current theoretical models. None of them, however, yields satisfactory agreement with the experimental data presented here. These new data may facilitate future development of adequate models for description of the fragmentation process.
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11.
  • Wamers, F., et al. (författare)
  • Diverse mechanisms in proton knockout reactions from the Borromean nucleus Ne-17
  • 2023
  • Ingår i: European Physical Journal A. - : Springer. - 1434-6001 .- 1434-601X. ; 59
  • Tidskriftsartikel (refereegranskat)abstract
    • Nucleon knockout experiments using beryllium or carbon targets reveal a strong dependence of the quenching factors, i.e., the ratio (Rs) of theoretical to the experimental spectroscopic factors (C2S), on the proton-neutron asymmetry in the nucleus under study. However, this dependence is greatly reduced when a hydrogen target is used. To understand this phenomenon, exclusive H-1(Ne-17, 2p F-16) and inclusive C-12(Ne-17, 2p 1(6)F)X, 1(2)C(Ne-17, F-16)X as well as 1H(Ne-17,(16) F)X(X-denotes undetected reaction products) reactions with F-16 in the ground and excited states were anal- ysed. The longitudinal momentum distribution of F-16 and the correlations between the detached protons were studied. In the case of the carbon target, there is a significant deviation from the predictions of the eikonal model. The eikonal approximation was used to extract spectroscopic factor values (CS)-S-2. The experimental (CS)-S-2 value obtained with C target is markedly lower than that for H target. This is interpreted as rescattering due to simultaneous nucleon knockout from both reaction partners, Ne-17 and C-12.
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12.
  • Wamers, F., et al. (författare)
  • New insight into knockout reactions from the two-proton halo nucleus Ne 17
  • 2024
  • Ingår i: Physical Review C. - 2469-9985 .- 2469-9993. ; 109:5
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: The unexplained disagreement in the dependence of spectroscopic factors (C2Sexp) on the binding energy obtained by nucleon knockout using different targets is still a puzzle that needs to be addressed. Purpose: To find an explanation of this riddle through exclusive measurements using different targets. Method: The exclusive measurements were performed by using a Ne17 beam with an energy of 500 MeV/u incident on C and CH2 targets. Through the standard theoretical approach, C2Sexp were derived from the analysis of the experimental data on proton ejection from the proton halo in Ne17 as well as from its core O15. Result: For the C target, proton ejection from the proton halo gave C2Sexp about 37% smaller than for the H target. But when protons are ejected from the core of Ne17, C2Sexp are identical within statistical uncertainties. Conclusion: An explanation for the difference in C2Sexp could be the removal of both halo protons, a more important reaction pathway for the C target. The C2Sexp values obtained by analyzing the proton ejection from the core indicate that it is not affected by the interaction with the halo protons.
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13.
  • Altstadt, S.G., et al. (författare)
  • B-13,B-14(n,gamma) via Coulomb Dissociation for Nucleosynthesis towards the r-Process
  • 2014
  • Ingår i: Nuclear Data Sheets. - : Elsevier BV. - 1095-9904 .- 0090-3752. ; 120, s. 197-200
  • Konferensbidrag (refereegranskat)abstract
    • Radioactive beams of 14,15B produced by fragmentation of a primary 40Ar beam were directed onto a Pb target to investigate the neutron breakup within the Coulomb field. The experiment was performed at the LAND/R3B setup. Preliminary results for the Coulomb dissociation cross sections as well as for the astrophysically interesting inverse reactions, 13,14B(n,γ), are presented.
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14.
  • Bonham, LW, et al. (författare)
  • Genetic variation across RNA metabolism and cell death gene networks is implicated in the semantic variant of primary progressive aphasia
  • 2019
  • Ingår i: Scientific reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 9:1, s. 10854-
  • Tidskriftsartikel (refereegranskat)abstract
    • The semantic variant of primary progressive aphasia (svPPA) is a clinical syndrome characterized by neurodegeneration and progressive loss of semantic knowledge. Unlike many other forms of frontotemporal lobar degeneration (FTLD), svPPA has a highly consistent underlying pathology composed of TDP-43 (a regulator of RNA and DNA transcription metabolism). Previous genetic studies of svPPA are limited by small sample sizes and a paucity of common risk variants. Despite this, svPPA’s relatively homogenous clinicopathologic phenotype makes it an ideal investigative model to examine genetic processes that may drive neurodegenerative disease. In this study, we used GWAS metadata, tissue samples from pathologically confirmed frontotemporal lobar degeneration, and in silico techniques to identify and characterize protein interaction networks associated with svPPA risk. We identified 64 svPPA risk genes that interact at the protein level. The protein pathways represented in this svPPA gene network are critical regulators of RNA metabolism and cell death, such as SMAD proteins and NOTCH1. Many of the genes in this network are involved in TDP-43 metabolism. Contrary to the conventional notion that svPPA is a clinical syndrome with few genetic risk factors, our analyses show that svPPA risk is complex and polygenic in nature. Risk for svPPA is likely driven by multiple common variants in genes interacting with TDP-43, along with cell death,x` working in combination to promote neurodegeneration.
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15.
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16.
  • Marganiec, C., et al. (författare)
  • Coulomb breakup of 17Ne from the viewpoint of nuclear astrophysics
  • 2013
  • Ingår i: Proceedings of Science.
  • Konferensbidrag (refereegranskat)abstract
    • By the Coulomb breakup of 17Ne, the time-reversed reaction 15O(2p,γ)17Ne has been studied. This reaction might play an important role in the rp process, as a break-out reaction of the hot CNO cycle. The secondary 17Ne ion beam with an energy of 500 MeV/nucleon has been dissociated in a Pb target. The reaction products have been detected with the LAND-R3B experimental setup at GSI. The preliminary differential and integral Coulomb dissociation cross section sCoul has been determined, which then will be converted into a photo-absorption cross section sphot o, and a two-proton radiative capture cross section σcap. Additionally, information about the structure of the 17Ne, a potential two-proton halo nucleus, will be received. The analysis is in progress.
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17.
  • Marganiec, J, et al. (författare)
  • Experimental study of the 15O(2p ,γ)17Ne cross section by Coulomb Dissociation for the rp process
  • 2016
  • Ingår i: Journal of Physics Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596.
  • Konferensbidrag (refereegranskat)abstract
    • The time-reversed reaction 15O(2p,γ)17Ne has been studied by the Coulomb dissociation technique. Secondary 17Ne ion beams at 500 AMeV have been produced by fragmentation reactions of 20Ne in a beryllium production target and dissociated on a secondary Pb target. The incoming beam and the reaction products have been identified with the kinematically complete LAND-R3B experimental setup at GSI. The excitation energy prior to decay has been reconstructed by using the invariant-mass method. The preliminary differential and integral Coulomb Dissociation cross sections (σCoul) have been calculated, which provide a photoabsorption (σphoto) and a radiative capture cross section (σcap). Additionally, important information about the nuclear structure of the 17Ne nucleus will be obtained. The analysis is in progress.
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18.
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19.
  • Wamers, F., et al. (författare)
  • Comparison of electromagnetic and nuclear dissociation of Ne-17
  • 2018
  • Ingår i: Physical Review C. - : AMER PHYSICAL SOC. - 2469-9985 .- 2469-9993. ; 97:3
  • Tidskriftsartikel (refereegranskat)abstract
    • The Borromean drip-line nucleus Ne-17 has been suggested to possess a two-proton halo structure in its ground state. In the astrophysical rp-process, where the two-proton capture reaction O-15(2p,gamma) Ne-17 plays an important role, the calculated reaction rate differs by several orders of magnitude between different theoretical approaches. To add to the understanding of the Ne-17 structure we have studied nuclear and electromagnetic dissociation. A 500 MeV/u Ne-17 beam was directed toward lead, carbon, and polyethylene targets. Oxygen isotopes in the final state were measured in coincidence with one or two protons. Different reaction branches in the dissociation of Ne-17 were disentangled. The relative populations of s and d states in F-16 were determined for light and heavy targets. The differential cross section for electromagnetic dissociation (EMD) shows a continuous internal energy spectrum in the three-body system O-15 + 2p. The Ne-17 EMD data were compared to current theoretical models. None of them, however, yields satisfactory agreement with the experimental data presented here. These new data may facilitate future development of adequate models for description of the fragmentation process.
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20.
  • Wamers, F., et al. (författare)
  • Exclusive measurements of nuclear breakup reactions of 17Ne
  • 2014
  • Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 66
  • Konferensbidrag (refereegranskat)abstract
    • We have studied one-proton-removal reactions of about 500MeV/u 17Ne beams on a carbon target at the R3B/LAND setup at GSI by detecting beam-like 15O-p and determining their relative-energy distribution. We exclusively selected the removal of a 17Ne halo proton, and the Glauber-model analysis of the 16F momentum distribution resulted in an s2 contribution in the 17Ne ground state of about 40%. © Owned by the authors, published by EDP Sciences, 2014.
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21.
  • Aksouh, F., et al. (författare)
  • STUDY OF THE O-15(2p,gamma)Ne-17 CROSS SECTION BY COULOMB DISSOCIATION OF Ne-17 FOR THE rp PROCESS OF NUCLEOSYNTHESIS
  • 2014
  • Ingår i: Acta Physica Polonica, Series B.. - 1509-5770 .- 0587-4254. ; 45:2, s. 229-234
  • Tidskriftsartikel (refereegranskat)abstract
    • The O-15(2p, gamma)Ne-17 cross section has been studied by the inverse reaction, the Coulomb dissociation of Ne-17. The experiment has been performed at the GSI. The Ne-17 excitation energy prior to decay has been reconstructed by using the invariant-mass method. The preliminary differential and integral Coulomb dissociation cross sections (sigma(Coul)) have been extracted, which provide a photoabsorption (sigma(photo)) and a radiative capture cross section (sigma(cap)). Additionally, important information about the Ne-17 nuclear structure will be obtained. The analysis is in progress.
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22.
  • Atar, L., et al. (författare)
  • Quasifree (p, 2p) Reactions on Oxygen Isotopes: Observation of Isospin Independence of the Reduced Single-Particle Strength
  • 2018
  • Ingår i: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 120:5
  • Tidskriftsartikel (refereegranskat)abstract
    • Quasifree one-proton knockout reactions have been employed in inverse kinematics for a systematic study of the structure of stable and exotic oxygen isotopes at the R3B/LAND setup with incident beam energies in the range of 300-450 MeV/u. The oxygen isotopic chain offers a large variation of separation energies that allows for a quantitative understanding of single-particle strength with changing isospin asymmetry. Quasifree knockout reactions provide a complementary approach to intermediate-energy one-nucleon removal reactions. Inclusive cross sections for quasifree knockout reactions of the type OA(p,2p)NA-1 have been determined and compared to calculations based on the eikonal reaction theory. The reduction factors for the single-particle strength with respect to the independent-particle model were obtained and compared to state-of-the-art ab initio predictions. The results do not show any significant dependence on proton-neutron asymmetry.
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23.
  • Boillos, J. M., et al. (författare)
  • Isotopic cross sections of fragmentation residues produced by light projectiles on carbon near
  • 2022
  • Ingår i: Physical Review C. - 2469-9993 .- 2469-9985. ; 105:1
  • Tidskriftsartikel (refereegranskat)abstract
    • We measured 135 cross sections of residual nuclei produced in fragmentation reactions of C12, N14, and O13−16,20,22 projectiles impinging on a carbon target at kinetic energies of near 400A MeV, most of them for the first time, with the RB3/LAND setup at the GSI facility in Darmstadt (Germany). The use of this state-of-the-art experimental setup in combination with the inverse kinematics technique gave the full identification in atomic and mass numbers of fragmentation residues with a high precision. The cross sections of these residues were determined with uncertainties below 20% for most of the cases. These data are compared to other previous measurements with stable isotopes and are also used to benchmark different model calculations.
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24.
  • Cronin, M. F., et al. (författare)
  • Developing an Observing Air-Sea Interactions Strategy (OASIS) for the global ocean
  • 2022
  • Ingår i: Ices Journal of Marine Science. - : Oxford University Press (OUP). - 1054-3139 .- 1095-9289. ; 80:2, s. 367-73
  • Tidskriftsartikel (refereegranskat)abstract
    • The Observing Air-Sea Interactions Strategy (OASIS) is a new United Nations Decade of Ocean Science for Sustainable Development programme working to develop a practical, integrated approach for observing air-sea interactions globally for improved Earth system (including ecosystem) forecasts, CO2 uptake assessments called for by the Paris Agreement, and invaluable surface ocean information for decision makers. Our "Theory of Change" relies upon leveraged multi-disciplinary activities, partnerships, and capacity strengthening. Recommendations from >40 OceanObs'19 community papers and a series of workshops have been consolidated into three interlinked Grand Ideas for creating #1: a globally distributed network of mobile air-sea observing platforms built around an expanded array of long-term time-series stations; #2: a satellite network, with high spatial and temporal resolution, optimized for measuring air-sea fluxes; and #3: improved representation of air-sea coupling in a hierarchy of Earth system models. OASIS activities are organized across five Theme Teams: (1) Observing Network Design & Model Improvement; (2) Partnership & Capacity Strengthening; (3) UN Decade OASIS Actions; (4) Best Practices & Interoperability Experiments; and (5) Findable-Accessible-Interoperable-Reusable (FAIR) models, data, and OASIS products. Stakeholders, including researchers, are actively recruited to participate in Theme Teams to help promote a predicted, safe, clean, healthy, resilient, and productive ocean.
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25.
  • Güsten, R., et al. (författare)
  • APEX - The Atacama Pathfinder Experiment
  • 2006
  • Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. ; 6267 I
  • Konferensbidrag (refereegranskat)abstract
    • APEX, the Atacama Pathfinder Experiment, has been successfully commissioned and is in operation now. This novel submillimeter telescope is located at 5107 m altitude on Llano de Chajnantor in the Chilean High Andes, on what is considered one of the world's outstanding sites for submillimeter astronomy. The primary reflector with 12 m diameter has been carefully adjusted by means of holography. Its surface smoothness of 17-18 μm makes APEX suitable for observations up to 200 μm, through all atmospheric submm windows accessible from the ground.
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26.
  • Heine, M., et al. (författare)
  • Determination of the neutron-capture rate of C-17 for r-process nucleosynthesis
  • 2017
  • Ingår i: Physical Review C. - 2469-9985 .- 2469-9993. ; 95:1, s. Article no 014613 -
  • Tidskriftsartikel (refereegranskat)abstract
    • With the (RB)-B-3-LAND setup at GSI we have measured exclusive relative-energy spectra of the Coulomb dissociation of C-18 at a projectile energy around 425A MeV on a lead target, which are needed to determine the radiative neutron-capture cross sections of C-17 into the ground state of C-18. Those data have been used to constrain theoretical calculations for transitions populating excited states in C-18. This allowed to derive the astrophysical cross section sigma(n gamma)*. accounting for the thermal population of C-17 target states in astrophysical scenarios. The experimentally verified capture rate is significantly lower than those of previously obtained Hauser-Feshbach estimations at temperatures T-9
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27.
  • Hinke, C. B., et al. (författare)
  • Superallowed Gamow-Teller decay of the doubly magic nucleus 100Sn
  • 2012
  • Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 486:7403, s. 341-345
  • Tidskriftsartikel (refereegranskat)abstract
    • The shell structure of atomic nuclei is associated with 'magic numbers' and originates in the nearly independent motion of neutrons and protons in a mean potential generated by all nucleons. During beta(+)-decay, a proton transforms into a neutron in a previously not fully occupied orbital, emitting a positron-neutrino pair with either parallel or antiparallel spins, in a Gamow-Teller or Fermi transition, respectively. The transition probability, or strength, of a Gamow-Teller transition depends sensitively on the underlying shell structure and is usually distributed among many states in the neighbouring nucleus. Here we report measurements of the half-life and decay energy for the decay of Sn-100, the heaviest doubly magic nucleus with equal numbers of protons and neutrons. In the beta-decay of Sn-100, a large fraction of the strength is observable because of the large decay energy. We determine the largest Gamow-Teller strength so far measured in allowed nuclear beta-decay, establishing the 'superallowed' nature of this Gamow-Teller transition. The large strength and the low-energy states in the daughter nucleus, In-100, are well reproduced by modern, large-scale shell model calculations.
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28.
  • Marganiec, J., et al. (författare)
  • Coulomb and nuclear excitations of narrow resonances in 17Ne
  • 2016
  • Ingår i: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 759, s. 200-205
  • Tidskriftsartikel (refereegranskat)abstract
    • New experimental data for dissociation of relativistic 17Ne projectiles incident on targets of lead, carbon, and polyethylene targets at GSI are presented. Special attention is paid to the excitation and decay of narrow resonant states in 17Ne. Distributions of internal energy in the O15+p+p three-body system have been determined together with angular and partial-energy correlations between the decay products in different energy regions. The analysis was done using existing experimental data on 17Ne and its mirror nucleus 17N. The isobaric multiplet mass equation is used for assignment of observed resonances and their spins and parities. A combination of data from the heavy and light targets yielded cross sections and transition probabilities for the Coulomb excitations of the narrow resonant states. The resulting transition probabilities provide information relevant for a better understanding of the 17Ne structure.
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29.
  • Marganiec, J., et al. (författare)
  • Experimental study of the O-15(2p, gamma) Ne-17 cross section by Coulomb Dissociation for the rp process
  • 2016
  • Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 665:1
  • Konferensbidrag (refereegranskat)abstract
    • The time-reversed reaction O-15(2p, gamma) Ne-17 has been studied by the Coulomb dissociation technique. Secondary 17Ne ion beams at 500 AMeV have been produced by fragmentation reactions of Ne-20 in a beryllium production target and dissociated on a secondary Pb target. The incoming beam and the reaction products have been identified with the kinematically complete LAND-(RB)-B-3 experimental setup at GSI. The excitation energy prior to decay has been reconstructed by using the invariant-mass method. The preliminary differential and integral Coulomb Dissociation cross sections (sigma(Coul)) have been calculated, which provide a photoabsorption (sigma(photo)) and a radiative capture cross section (sigma(cap)). Additionally, important information about the nuclear structure of the Ne-17 nucleus will be obtained. The analysis is in progress.
  •  
30.
  • Ribeiro, G., et al. (författare)
  • Structure of Be-13 studied in proton knockout from B-14
  • 2018
  • Ingår i: Physical Review C. - 2469-9985 .- 2469-9993. ; 98:2
  • Tidskriftsartikel (refereegranskat)abstract
    • The neutron-unbound isotope Be-13 has been studied in several experiments using different reactions, different projectile energies, and different experimental setups. There is, however, no real consensus in the interpretation of the data, in particular concerning the structure of the low-lying excited states. Gathering new experimental information, which may reveal the Be-13 structure, is a challenge, particularly in light of its bridging role between Be-12, where the N = 8 neutron shell breaks down, and the Borromean halo nucleus Be-14. The purpose of the present study is to investigate the role of bound excited states in the reaction product Be-12 after proton knockout from B-14, by measuring coincidences between Be-12, neutrons, and gamma rays originating from de-excitation of states fed by neutron decay of Be-13. The Be-13 isotopes were produced in proton knockout from a 400 MeV/nucleon B-14 beam impinging on a CH2 target. The Be-12-n relative-energy spectrum d sigma/dE(fn) was obtained from coincidences between Be-12(g.s.) and a neutron, and also as threefold coincidences by adding gamma rays, from the de-excitation of excited states in Be-12. Neutron decay from the first 5/2(+) state in Be-13 to the 2(+) state in Be-12 at 2.11 MeV is confirmed. An energy independence of the proton-knockout mechanism is found from a comparison with data taken with a 35 MeV/nucleon B-14 beam. A low-lying p-wave resonance in Be-13(1/2(-)) is confirmed by comparing proton- and neutron-knockout data from B-14 and Be-14.
  •  
31.
  • Röder, M., et al. (författare)
  • Coulomb dissociation of 20,21 N
  • 2016
  • Ingår i: Physical Review C - Nuclear Physics. - 2469-9985 .- 2469-9993 .- 0556-2813. ; 93:6
  • Tidskriftsartikel (refereegranskat)abstract
    • Neutron-rich light nuclei and their reactions play an important role in the creation of chemical elements. Here, data from a Coulomb dissociation experiment on N20,21 are reported. Relativistic N20,21 ions impinged on a lead target and the Coulomb dissociation cross section was determined in a kinematically complete experiment. Using the detailed balance theorem, the N19(n,γ)N20 and N20(n,γ)N21 excitation functions and thermonuclear reaction rates have been determined. The N19(n,γ)N20 rate is up to a factor of 5 higher at T
  •  
32.
  • Thies, Ronja, 1987, et al. (författare)
  • Systematic investigation of projectile fragmentation using beams of unstable B and C isotopes
  • 2016
  • Ingår i: Physical Review C - Nuclear Physics. - 2469-9985 .- 2469-9993 .- 0556-2813. ; 93:5
  • Tidskriftsartikel (refereegranskat)abstract
    • Models describing nuclear fragmentation and fragmentation fission deliver important input for planning nuclear physics experiments and future radioactive ion beam facilities. These models are usually benchmarked against data from stable beam experiments. In the future, two-step fragmentation reactions with exotic nuclei as stepping stones are a promising tool for reaching the most neutron-rich nuclei, creating a need for models to describe also these reactions. Purpose: We want to extend the presently available data on fragmentation reactions towards the light exotic region on the nuclear chart. Furthermore, we want to improve the understanding of projectile fragmentation especially for unstable isotopes. Method: We have measured projectile fragments from C10,12-18 and B10-15 isotopes colliding with a carbon target. These measurements were all performed within one experiment, which gives rise to a very consistent data set. We compare our data to model calculations. Results: One-proton removal cross sections with different final neutron numbers (1pxn) for relativistic C10,12-18 and B10-15 isotopes impinging on a carbon target. Comparing model calculations to the data, we find that the epax code is not able to describe the data satisfactorily. Using abrabla07 on the other hand, we find that the average excitation energy per abraded nucleon needs to be decreased from 27 MeV to 8.1 MeV. With that decrease abrabla07 describes the data surprisingly well. Conclusions: Extending the available data towards light unstable nuclei with a consistent set of new data has allowed a systematic investigation of the role of the excitation energy induced in projectile fragmentation. Most striking is the apparent mass dependence of the average excitation energy per abraded nucleon. Nevertheless, this parameter, which has been related to final-state interactions, requires further study.
  •  
33.
  • Wadsworth, R., et al. (författare)
  • THE NORTHWEST FRONTIER : SPECTROSCOPY OF N similar to Z NUCLEI BELOW MASS 100
  • 2009
  • Ingår i: Acta Physica Polonica B. - 0587-4254 .- 1509-5770. ; 40:3, s. 611-620
  • Tidskriftsartikel (refereegranskat)abstract
    • The spectroscopy and structure of excited states of N similar to Z nuclei in the mass 70-100 region has been investigated using two techniques. In the A similar to 70-80 region fusion evaporation reactions coupled with the recoil-beta-tagging method have been employed at Jyvaskyla to study low-lying states in odd-odd N = Z nuclei. Results from these and other data for known odd-odd nuclei above mass 60 will be discussed. In the heavier mass 90 region a fragmentation experiment has been performed using the RIS-ING/FRS setup at GSI. This experiment was primarily aimed at searching for spin gap isomers in nuclei around A similar to 96. The objectives of the latter experiment will be discussed.
  •  
34.
  • Diaz Fernandez, Paloma, 1983, et al. (författare)
  • Quasifree (p, pN) scattering of light neutron-rich nuclei near N=14
  • 2018
  • Ingår i: Physical Review C. - 2469-9985 .- 2469-9993. ; 97:2
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: For many years, quasifree scattering reactions in direct kinematics have been extensively used to study the structure of stable nuclei, demonstrating the potential of this approach. The (RB)-B-3 collaboration has performed a pilot experiment to study quasifree scattering reactions in inverse kinematics for a stable C-12 beam. The results from that experiment constitute the first quasifree scattering results in inverse and complete kinematics. This technique has lately been extended to exotic beams to investigate the evolution of shell structure, which has attracted much interest due to changes in shell structure if the number of protons or neutrons is varied. Purpose: In this work we investigate for the first time the quasifree scattering reactions (p, pn) and (p, 2p) simultaneously for the same projectile in inverse and complete kinematics for radioactive beams with the aim to study the evolution of single-particle properties from N = 14 to N = 15. Method: The structure of the projectiles O-23, O-22, and N-21 has been studied simultaneously via (p, pn) and (p, 2p) quasifree knockout reactions in complete inverse kinematics, allowing the investigation of proton and neutron structure at the same time. The experimental data were collected at the (RB)-B-3-LAND setup at GSI at beam energies of around 400 MeV/u. Two key observables have been studied to shed light on the structure of those nuclei: the inclusive cross sections and the corresponding momentum distributions. Conclusions: The knockout reactions (p, pn) and (p, 2p) with radioactive beams in inverse kinematics have provided important and complementary information for the study of shell evolution and structure. For the (p, pn) channels, indications of a change in the structure of these nuclei moving from N = 14 to N = 15 have been observed, i.e., from the 0d(5/2) shell to the 1s(1/2). This supports previous observations of a subshell closure at N = 14 for neutron-rich oxygen isotopes and its weakening for the nitrogen isotopes.
  •  
35.
  • Ferrari, Raffaele, et al. (författare)
  • Frontotemporal dementia and its subtypes: a genome-wide association study.
  • 2014
  • Ingår i: Lancet Neurology. - 1474-4465. ; 13:7, s. 686-699
  • Tidskriftsartikel (refereegranskat)abstract
    • Frontotemporal dementia (FTD) is a complex disorder characterised by a broad range of clinical manifestations, differential pathological signatures, and genetic variability. Mutations in three genes-MAPT, GRN, and C9orf72-have been associated with FTD. We sought to identify novel genetic risk loci associated with the disorder.
  •  
36.
  • Gao, YX, et al. (författare)
  • Mendelian randomization implies no direct causal association between leukocyte telomere length and amyotrophic lateral sclerosis
  • 2020
  • Ingår i: Scientific reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 10:1, s. 12184-
  • Tidskriftsartikel (refereegranskat)abstract
    • We employed Mendelian randomization (MR) to evaluate the causal relationship between leukocyte telomere length (LTL) and amyotrophic lateral sclerosis (ALS) with summary statistics from genome-wide association studies (n = ~ 38,000 for LTL and ~ 81,000 for ALS in the European population; n = ~ 23,000 for LTL and ~ 4,100 for ALS in the Asian population). We further evaluated mediation roles of lipids in the pathway from LTL to ALS. The odds ratio per standard deviation decrease of LTL on ALS was 1.10 (95% CI 0.93–1.31, p = 0.274) in the European population and 0.75 (95% CI 0.53–1.07, p = 0.116) in the Asian population. This null association was also detected between LTL and frontotemporal dementia in the European population. However, we found that an indirect effect of LTL on ALS might be mediated by low density lipoprotein (LDL) or total cholesterol (TC) in the European population. These results were robust against extensive sensitivity analyses. Overall, our MR study did not support the direct causal association between LTL and the ALS risk in neither population, but provided suggestive evidence for the mediation role of LDL or TC on the influence of LTL and ALS in the European population.
  •  
37.
  • Golosio, B., et al. (författare)
  • The FIRST experiment for nuclear fragmentation measurements at GSI
  • 2011
  • Ingår i: Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC), 2011 IEEE. ; , s. 2277-2280
  • Konferensbidrag (refereegranskat)abstract
    • Nuclear fragmentation processes are relevant in different fields of physics concerning both basic research and applications. FIRST (Fragmentation of Ions Relevant for Space and Therapy) is an experiment aimed at the measurement of double differential cross sections (DDCS), with respect to kinetic energy and scattering polar angle, of nuclear fragmentation processes relevant for hadron therapy and for space radiation protection applications, in the energy range between 100 and 1000 MeV/u. The experiment was mounted at the GSI laboratories of Darmstadt, in Germany. A first data taking was performed in August 2011, using 400 MeV/u 12C on carbon and gold targets. In this work we present a description of the experimental apparatus and some figures from the data acquisition and from the preliminary work on data analysis
  •  
38.
  • Gottardo, A., et al. (författare)
  • New Isomers in the Neutron-Rich Region Beyond 208Pb
  • 2014
  • Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2100-014X. - 9782759811755 - 9782759811762 ; 66, s. 02043-02043
  • Konferensbidrag (refereegranskat)abstract
    • The region of neutron-rich nuclei beyond 208Pb has been very difficult to explore due to its high mass and exoticity. However, recent experimental improvements allowed one to perform a quite extended isomer decay spectroscopy of these nuclei.
  •  
39.
  • Holl, M., et al. (författare)
  • Quasi-free neutron and proton knockout reactions from light nuclei in a wide neutron-to-proton asymmetry range
  • 2019
  • Ingår i: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 795, s. 682-688
  • Tidskriftsartikel (refereegranskat)abstract
    • The quasi-free scattering reactions 11C(p,2p) and 10,11,12C(p,pn) have been studied in inverse kinematics at beam energies of 300–400 MeV/u at the R3B-LAND setup. The outgoing proton-proton and proton-neutron pairs were detected in coincidence with the reaction fragments in kinematically complete measurements. The efficiency to detect these pairs has been obtained from GEANT4 simulations which were tested using the 12C(p,2p) and 12C(p,pn) reactions. Experimental cross sections and momentum distributions have been obtained and compared to DWIA calculations based on eikonal theory. The new results reported here are combined with previously published cross sections for quasi-free scattering from oxygen and nitrogen isotopes and together they enable a systematic study of the reduction of single-particle strength compared to predictions of the shell model over a wide neutron-to-proton asymmetry range. The combined reduction factors show a weak or no dependence on isospin asymmetry, in contrast to the strong dependency reported in nucleon-removal reactions induced by nuclear targets at lower energies. However, the reduction factors for (p,2p) are found to be 'significantly smaller than for (p,pn) reactions for all investigated nuclei.
  •  
40.
  • Marganiec, J., et al. (författare)
  • Studies of continuum states in (16) Ne using three-body correlation techniques
  • 2015
  • Ingår i: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-601X .- 1434-6001. ; 51:1, s. 1-9
  • Tidskriftsartikel (refereegranskat)abstract
    • Two-proton decay of the unbound nucleus Ne-16 , produced in one-neutron knockout from a 500 MeV/u Ne-17 beam, has been studied at GSI. The ground state, at a resonance energy 1.388(15) MeV, ( MeV) above the O-14 +p+p threshold, and two narrow resonances at MeV and 7.57(6) MeV have been investigated. A comparison of the energy difference between the first excited 2(+) state and the 0(+) ground state in Ne-16 with its mirror nucleus C-16 reveals a small Thomas-Ehrman shift (TES) of keV. A trend of the TES for the T = 2 quintet is obtained by completing the known data with a prediction for F-16 obtained from an IMME analysis. The decay mechanisms of the observed three resonances were revealed from an analysis of the energy and angular correlations of the O-14 +p+p decay products. The ground state decay can be considered as a genuine three-body (democratic) mode and the excited states decay sequentially via states in the intermediate nucleus F-15 , the 3.22 MeV state predominantly via the F-15 ground-state resonance, while the 7.57 MeV state decays via the 5/2(+) resonance in F-15 at 2.8 MeV above the O-14 +p+p threshold. Further, from an analysis of angular correlations, the spin-parity of the 7.57 MeV state has been determined as and assigned as the third 2(+) state in Ne-16 based on a comparison with C-16.
  •  
41.
  • Pleskac, R., et al. (författare)
  • The FIRST experiment at GSI
  • 2012
  • Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 678, s. 130-138
  • Tidskriftsartikel (refereegranskat)abstract
    • The FIRST (Fragmentation of Ions Relevant for Space and Therapy) experiment at the SIS accelerator of GSl laboratory in Darmstadt has been designed for the measurement of ion fragmentation crosssections at different angles and energies between 100 and 1000 MeV/nucleon. Nuclear fragmentation processes are relevant in several fields of basic research and applied physics and are of particular interest for tumor therapy and for space radiation protection applications. The start of the scientific program of the FIRST experiment was on summer 2011 and was focused on the measurement of 400 MeV/nucleon C-12 beam fragmentation on thin (8 mm) graphite target. The detector is partly based on an already existing setup made of a dipole magnet (ALADiN). a time projection chamber (TP-MUSIC IV), a neutron detector (LAND) and a time of flight scintillator system (TOFWALL). This pre-existing setup has been integrated with newly designed detectors in the Interaction Region, around the carbon target placed in a sample changer. The new detectors are a scintillator Start Counter, a Beam Monitor drift chamber, a silicon Vertex Detector and a Proton Tagger scintillator system optimized for the detection of light fragments emitted at large angles. In this paper we review the experimental setup, then we present the simulation software, the data acquisition system and finally the trigger strategy of the experiment.
  •  
42.
  • Polettini, M., et al. (författare)
  • Decay studies in the A∼225 Po-Fr region from the DESPEC campaign at GSI in 2021
  • 2022
  • Ingår i: Il Nuovo Cimento. - : Società Italiana di Fisica. - 2037-4909. ; 45:5
  • Tidskriftsartikel (refereegranskat)abstract
    • The HISPEC-DESPEC collaboration aims at investigating the structure of exotic nuclei formed in fragmentation reactions with decay spectroscopy measurements, as part of the FAIR Phase-0 campaign at GSI. This paper reports on first results of an experiment performed in spring 2021, with a focus on beta-decaystudies in the Po-Fr nuclei in the 220 < A <230 island of octupole deformation exploiting the DESPEC setup. Ion-beta correlations and fast-timing techniques are being employed, giving an insight into this difficult-to-reach region.
  •  
43.
  • Revel, A., et al. (författare)
  • Strong Neutron Pairing in core+4n Nuclei
  • 2018
  • Ingår i: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 120:15
  • Tidskriftsartikel (refereegranskat)abstract
    • The emission of neutron pairs from the neutron-rich N=12 isotones C18 and O20 has been studied by high-energy nucleon knockout from N19 and O21 secondary beams, populating unbound states of the two isotones up to 15 MeV above their two-neutron emission thresholds. The analysis of triple fragment-n-n correlations shows that the decay N19(-1p)C18∗→C16+n+n is clearly dominated by direct pair emission. The two-neutron correlation strength, the largest ever observed, suggests the predominance of a C14 core surrounded by four valence neutrons arranged in strongly correlated pairs. On the other hand, a significant competition of a sequential branch is found in the decay O21(-1n)O20∗→O18+n+n, attributed to its formation through the knockout of a deeply bound neutron that breaks the O16 core and reduces the number of pairs.
  •  
44.
  • Syndikus, I., et al. (författare)
  • Probing the Z = 6 spin-orbit shell gap with (p,2p) quasi-free scattering reactions
  • 2020
  • Ingår i: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 809
  • Tidskriftsartikel (refereegranskat)abstract
    • The evolution of the traditional nuclear magic numbers away from the valley of stability is an active field of research. Experimental efforts focus on providing key spectroscopic information that will shed light into the structure of exotic nuclei and understanding the driving mechanism behind the shell evolution. In this work, we investigate the Z=6 spin-orbit shell gap towards the neutron dripline. To do so, we employed NA(p,2p)CA−1 quasi-free scattering reactions to measure the proton component of the 21+ state of 16,18,20C. The experimental findings support the notion of a moderate reduction of the proton 1p1/2−1p3/2 spin-orbit splitting, at variance to recent claims for a prevalent Z=6 magic number towards the neutron dripline.
  •  
45.
  • Vandebrouck, M., et al. (författare)
  • Effective proton-neutron interaction near the drip line from unbound states in F-25,F-26
  • 2017
  • Ingår i: Physical Review C. - 2469-9985 .- 2469-9993. ; 96:5
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Odd-odd nuclei, around doubly closed shells, have been extensively used to study proton-neutron interactions. However, the evolution of these interactions as a function of the binding energy, ultimately when nuclei become unbound, is poorly known. The F-26 nucleus, composed of a deeply bound pi 0d(5/2) proton and an unbound v0d(3/2) neutron on top of an O-24 core, is particularly adapted for this purpose. The coupling of this proton and neutron results in a J(pi) = 1(1)(+) - 4(1)(+) multiplet, whose energies must be determined to study the influence of the proximity of the continuum on the corresponding proton-neutron interaction. The J(pi) = 1(1)(+), 2(1)(+), 4(1)(+) bound states have been determined, and only a clear identification of the J(pi) = 3(1)(+) is missing. Purpose: We wish to complete the study of the J(pi) = 1(1)(+) - 4(1)(+) multiplet in F-26, by studying the energy and width of the J(pi) = 3(1)(+) unbound state. The method was first validated by the study of unbound states in F-25, for which resonances were already observed in a previous experiment. Method: Radioactive beams of Ne-26 and Ne-27, produced at about 440AMeV by the fragment separator at the GSI facility were used to populate unbound states in F-25 and F-26 via one-proton knockout reactions on a CH2 target, located at the object focal point of the (RB)-B-3/LAND setup. The detection of emitted. rays and neutrons, added to the reconstruction of the momentum vector of the A - 1 nuclei, allowed the determination of the energy of three unbound states in F-25 and two in F-26. Results: Based on its width and decay properties, the first unbound state in F-25, at the relative energy of 49(9) keV, is proposed to be a J(pi) = 1/ 2(-) arising from a p1/2 proton- hole state. In F-26, the first resonance at 323(33) keV is proposed to be the J(pi) = 3(1)(+) member of the J(pi) = 1(1)(+) - 4(1)(+) multiplet. Energies of observed states in F-25,F-26 have been compared to calculations using the independent-particle shell model, a phenomenological shell model, and the ab initio valence-space in-medium similarity renormalization group method. Conclusions: The deduced effective proton- neutron interaction is weakened by about 30-40% in comparison to the models, pointing to the need for implementing the role of the continuum in theoretical descriptions or to a wrong determination of the atomic mass of F-26.
  •  
46.
  • Wamers, F., et al. (författare)
  • First Observation of the Unbound Nucleus Ne-15
  • 2014
  • Ingår i: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 112:13
  • Tidskriftsartikel (refereegranskat)abstract
    • We report on the first observation of the unbound proton-rich nucleus Ne-15. Its ground state and first excited state were populated in two-neutron knockout reactions from a beam of 500 MeV/u Ne-17. The Ne-15 ground state is found to be unbound by 2.522(66) MeV. The decay proceeds directly to O-13 with simultaneous two-proton emission. No evidence for sequential decay via the energetically allowed 2(-) and 1(-) states in F-14 is observed. The Ne-15 ground state is shown to have a strong configuration with two protons in the (sd) shell around O-13 with a 63(5)% (1s(1/2))(2) component.
  •  
47.
  • Antonov, A. N., et al. (författare)
  • The electron-ion scattering experiment ELISe at the International Facility for Antiproton and Ion Research (FAIR)-A conceptual design study
  • 2011
  • Ingår i: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. - : Elsevier BV. - 0168-9002 .- 0167-5087. ; 637:1, s. 60-76
  • Tidskriftsartikel (refereegranskat)abstract
    • The electron-ion scattering experiment ELISe is part of the installations envisaged at the new experimental storage ring at the International Facility for Antiproton and Ion Research (FAIR) in Darmstadt, Germany. It offers an unique opportunity to use electrons as probe in investigations of the structure of exotic nuclei. The conceptual design and the scientific challenges of ELISe are presented. (C) 2011 Elsevier B.V. All rights reserved.
  •  
48.
  • Beceiro-Novo, S., et al. (författare)
  • Coulomb dissociation of 27 P: A reaction of astrophysical interest
  • 2010
  • Ingår i: Proceedings of Science. - Trieste, Italy : Sissa Medialab. - 1824-8039. ; 100
  • Konferensbidrag (refereegranskat)abstract
    • The ground-state decay of 26Al(0+) (T 1/2=1.05× 106) has a shorter life-time than the Universe. The presence of this element in the Galaxy was measured via g-ray spectroscopy, showing that the nucleosynthesis of this element is an ongoing process in stars. The proton-capture reaction 26Si(p,γ) 27P competes with the production of 26Al(0+) by β-decay. Coulomb dissociation of 27P has been suggested as an indirect method to measure radiative-proton capture when the direct reaction is not feasible. Such an experiment was performed at GSI with a secondary 27P beam produced by fragmenting a 36Ar primary beam at 500 A MeV. Two main observables are preliminarily presented in this work: the reaction cross section and the relative-energy spectrum of the outgoing fragments © Copyright owned by the author(s).
  •  
49.
  • Blazhev, A, et al. (författare)
  • High-energy Excited States in 98Cd
  • 2010
  • Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6596. ; 205
  • Tidskriftsartikel (refereegranskat)abstract
    • In 98Cd a new high-energy isomeric γ-ray transition was identified, which confirms previous spin-parity assignments and enables for the first time the measurement of the E2 and E4 strength for the two decay branches of the isomer. Preliminary results on the 98Cd high-excitation level scheme are presented. A comparison to shell-model calculations as well as implications for the nuclear structure around 100Sn are discussed.
  •  
50.
  • Grawe, H., et al. (författare)
  • The (6+) isomer in 102Sn revisited : Neutron and proton effective charges close to the double shell closure
  • 2021
  • Ingår i: Physics Letters B. - : Elsevier. - 0370-2693 .- 1873-2445. ; 820
  • Tidskriftsartikel (refereegranskat)abstract
    • In a high-energy fragmentation experiment at GSI an Iπ = (6+) isomer and its γ-decay are identified in 102Sn, the two-neutron neighbour of the doubly-magic 100Sn. Its half-life is measured to be T1/2 = 367(11) ns. The possible existence of further isomers is discussed in the framework of large-scale shell model (LSSM) calculations including up to five particle-hole excitations of the 100Sn core. From the precise B(E2; 6+ → 4+) strength and the recently remeasured value for B(E2; 8+ → 6+) in the two-proton hole neighbour 98Cd effective E2 polarization charges for protons and neutrons were inferred including LSSM corrections within the full N=4 0hω space. The results are discussed in comparison to predicted and empirically determined effective operators.
  •  
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