| 1. |
- Akkoyun, S., et al.
(författare)
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AGATA - Advanced GAmma Tracking Array
- 2012
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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
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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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| 2. |
- Reifarth, R., et al.
(författare)
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Nuclear astrophysics with radioactive ions at FAIR
- 2016
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Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 665:1
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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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| 3. |
- Antoniou, Antonis C., et al.
(författare)
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Common alleles at 6q25.1 and 1p11.2 are associated with breast cancer risk for BRCA1 and BRCA2 mutation carriers
- 2011
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Ingår i: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 20:16, s. 3304-3321
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Tidskriftsartikel (refereegranskat)abstract
- Two single nucleotide polymorphisms (SNPs) at 6q25.1, near the ESR1 gene, have been implicated in the susceptibility to breast cancer for Asian (rs2046210) and European women (rs9397435). A genome-wide association study in Europeans identified two further breast cancer susceptibility variants: rs11249433 at 1p11.2 and rs999737 in RAD51L1 at 14q24.1. Although previously identified breast cancer susceptibility variants have been shown to be associated with breast cancer risk for BRCA1 and BRCA2 mutation carriers, the involvement of these SNPs to breast cancer susceptibility in mutation carriers is currently unknown. To address this, we genotyped these SNPs in BRCA1 and BRCA2 mutation carriers from 42 studies from the Consortium of Investigators of Modifiers of BRCA1/2. In the analysis of 14 123 BRCA1 and 8053 BRCA2 mutation carriers of European ancestry, the 6q25.1 SNPs (r(2) = 0.14) were independently associated with the risk of breast cancer for BRCA1 mutation carriers [ hazard ratio (HR) = 1.17, 95% confidence interval (CI): 1.11-1.23, P-trend = 4.5 x 10(-9) for rs2046210; HR = 1.28, 95% CI: 1.18-1.40, P-trend = 1.3 x 10(-8) for rs9397435], but only rs9397435 was associated with the risk for BRCA2 carriers (HR = 1.14, 95% CI: 1.01-1.28, P-trend = 0.031). SNP rs11249433 (1p11.2) was associated with the risk of breast cancer for BRCA2 mutation carriers (HR = 1.09, 95% CI: 1.02-1.17, P-trend = 0.015), but was not associated with breast cancer risk for BRCA1 mutation carriers (HR = 0.97, 95% CI: 0.92-1.02, P-trend = 0.20). SNP rs999737 (RAD51L1) was not associated with breast cancer risk for either BRCA1 or BRCA2 mutation carriers (P-trend = 0.27 and 0.30, respectively). The identification of SNPs at 6q25.1 associated with breast cancer risk for BRCA1 mutation carriers will lead to a better understanding of the biology of tumour development in these women.
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| 4. |
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| 5. |
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| 6. |
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| 7. |
- Kanungo, R., et al.
(författare)
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Exploring the anomaly in the interaction cross section and matter radius of 23O
- 2011
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Ingår i: Physical Review C - Nuclear Physics. - 2469-9985 .- 2469-9993 .- 0556-2813 .- 1089-490X. ; 84:6, s. art. no. 061304(R)-
-
Tidskriftsartikel (refereegranskat)abstract
- New measurements of the interaction cross sections of 22,23O at 900A MeV performed at the GSI, Darmstadt are reported that address the unsolved puzzle of the large cross section previously observed for 23O. The matter radii for these oxygen isotopes extracted through a Glauber model analysis are in good agreement with the new predictions of the ab initio coupled-cluster theory reported here. They are consistent with a 22O+neutron description of 23O as well.
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| 8. |
- Kanungo, R., et al.
(författare)
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Matter radii of 32-35Mg
- 2011
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Ingår i: Physical Review C - Nuclear Physics. - 2469-9985 .- 2469-9993 .- 0556-2813 .- 1089-490X. ; 83:2
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Tidskriftsartikel (refereegranskat)abstract
- The interaction cross sections of Mg32-35 at 900A MeV have been measurmed using the fragment separator at GSI. The deviation from the r(0)A(1/3) trend is slightly larger for Mg-35, signaling the possible formation of a longer tail in the neutron distribution for Mg-35. The radii extracted from a Glauber model analysis with Fermi densities are consistent with models predicting the development of neutron skins.
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| 9. |
- Kanungo, R., et al.
(författare)
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One-Neutron Removal Measurement Reveals O-24 as a New Doubly Magic Nucleus
- 2009
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Ingår i: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 102:15
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Tidskriftsartikel (refereegranskat)abstract
- The first measurement of the momentum distribution for one-neutron removal from O-24 at 920A MeV performed at GSI, Darmstadt is reported. The observed distribution has a width (FWHM) of 99 +/- 4 MeV/c in the projectile rest frame and a one-neutron removal cross section of 63 +/- 7 mb. The results are well explained with a nearly pure 2s(1/2) neutron spectroscopic factor of 1.74 +/- 0.19 within the eikonal model. This large s-wave probability shows a spherical shell closure thereby confirming earlier suggestions that O-24 is a new doubly magic nucleus.
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| 10. |
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| 11. |
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| 12. |
- Nociforo, C., et al.
(författare)
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One-neutron removal reactions on Al isotopes around the N=20 shell closure
- 2012
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X .- 2469-9985 .- 2469-9993. ; 85:4, s. 044312-1-044312-10
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Tidskriftsartikel (refereegranskat)abstract
- The one-neutron removal cross sections of neutron-rich Al isotopes and longitudinal momentum distributions of the residues have been measured for A=33 to 36 at relativistic energies (≈900 MeV/u). The inclusive data have been interpreted within the eikonal approximation. The evolution of the single-particle occupancy in the ground state of 33,34,35Al has been studied and compared with shell model predictions. The inferred 2s1/2 neutron occupancy in the 33Al ground-state wave function is 20% to 40% lower than the predicted one. The inclusive data do not exclude the presence of intruder states. Some intruder l=1 occupancy is found in 34Al, similarly to 33Mg. The single-particle 1f7/2 occupancy shows a gradual increase at N=22. Correspondingly, a decrease of the 1d3/2 strength has been observed.
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| 13. |
- Nociforo, C., et al.
(författare)
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Shell Closure N=16 in O-24
- 2009
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Ingår i: AIP Conference Proceedings. - 1551-7616 .- 0094-243X. ; 1165, s. 90-93 461
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Konferensbidrag (refereegranskat)abstract
- Advanced nuclear structure models predict the presence of the shell closures N=14, 16 in neutron-rich O isotopes rather than N=20. Spectroscopic investigations performed at the neutron drip line have recently confirmed such predictions showing that the O-24 is a doubly magic nucleus (Z=8, N=16). Predictions within the shell model calculation for the O-23,O-24 ground state have been confirmed measuring their spectroscopic factors. Results obtained in one-neutron removal reactions performed by using in-flight radioactive ion beams produced at the Fragment Separator FRS of GSI are reported.
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| 14. |
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| 15. |
- Antonov, A. N., et al.
(författare)
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The electron-ion scattering experiment ELISe at the International Facility for Antiproton and Ion Research (FAIR)-A conceptual design study
- 2011
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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
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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.
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| 16. |
- Grieser, M., et al.
(författare)
-
Storage ring at HIE-ISOLDE Technical design report
- 2012
-
Ingår i: The European Physical Journal Special Topics. - : Springer Science and Business Media LLC. - 1951-6355 .- 1951-6401. ; 207:1, s. 1-117
-
Forskningsöversikt (refereegranskat)abstract
- We propose to install a storage ring at an ISOL-type radioactive beam facility for the first time. Specifically, we intend to setup the heavy-ion, low-energy ring TSR at the HIE-ISOLDE facility in CERN, Geneva. Such a facility will provide a capability for experiments with stored secondary beams that is unique in the world. The envisaged physics programme is rich and varied, spanning from investigations of nuclear ground-state properties and reaction studies of astrophysical relevance, to investigations with highly-charged ions and pure isomeric beams. The TSR might also be employed for removal of isobaric contaminants from stored ion beams and for systematic studies within the neutrino beam programme. In addition to experiments performed using beams recirculating within the ring, cooled beams can also be extracted and exploited by external spectrometers for high-precision measurements. The existing TSR, which is presently in operation at the Max-Planck Institute for Nuclear Physics in Heidelberg, is well-suited and can be employed for this purpose. The physics cases as well as technical details of the existing ring facility and of the beam and infrastructure requirements at HIE-ISOLDE are discussed in the present technical design report.
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| 17. |
- Heil, M., et al.
(författare)
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A new Time-of-flight detector for the R 3 B setup
- 2022
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Ingår i: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-601X .- 1434-6001. ; 58:12
-
Tidskriftsartikel (refereegranskat)abstract
- We present the design, prototype developments and test results of the new time-of-flight detector (ToFD) which is part of the R3B experimental setup at GSI and FAIR, Darmstadt, Germany. The ToFD detector is able to detect heavy-ion residues of all charges at relativistic energies with a relative energy precision σΔE/ ΔE of up to 1% and a time precision of up to 14 ps (sigma). Together with an elaborate particle-tracking system, the full identification of relativistic ions from hydrogen up to uranium in mass and nuclear charge is possible.
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| 18. |
- Kanungo, R., et al.
(författare)
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Structure of Mg-33 sheds new light on the N=20 island of inversion
- 2010
-
Ingår i: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - Elsevier : Elsevier BV. - 0370-2693 .- 1873-2445. ; 685:4-5, s. 253-257
-
Tidskriftsartikel (refereegranskat)abstract
- The first reaction spectroscopy oil the ground state structure of Mg-33 through the measurement of the longitudinal momentum distribution from the one-neutron removal reaction Using a C target at 898A MeV is reported The experiment was performed at the FRS, GSI The distribution has a relatively narrow width (150 +/- 3 MeV/c (FWHM)) and the one-neutron removal cross-section is 74 +/- 4 mb An increased contribution from the (2)p(3/2) orbital is required to explain the observation showing its lowering compared to existing model predictions This provides new information regarding the configuration of Mg-33 and the island of inversion (C) 2010 Elsevier B V All rights reserved
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| 19. |
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| 20. |
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| 21. |
- Martel, I., et al.
(författare)
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An innovative Superconducting Recoil Separator for HIE-ISOLDE
- 2023
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Ingår i: Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms. - : ELSEVIER. - 0168-583X .- 1872-9584. ; 541, s. 176-179
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Tidskriftsartikel (refereegranskat)abstract
- The ISOLDE Scientific Infrastructure at CERN offers a unique range of post-accelerated radioactive beams. The scientific program can be improved with the “Isolde Superconducting Recoil Separator” (ISRS), an innovative spectrometer able to deliver unprecedented (A, Z) resolution. In this paper we present an overview of the physics and ongoing technical developments.
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| 22. |
- Abudurexiti, A, et al.
(författare)
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Taxonomy of the order Bunyavirales: update 2019
- 2019
-
Ingår i: Archives of virology. - : Springer Science and Business Media LLC. - 1432-8798 .- 0304-8608. ; 164:7, s. 1949-1965
-
Tidskriftsartikel (refereegranskat)
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| 23. |
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| 24. |
- Fynbo, H. O. U., et al.
(författare)
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Revised rates for the stellar triple-alpha process from measurement of C-12 nuclear resonances
- 2005
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687 .- 1476-4679. ; 433:7022, s. 136-139
-
Tidskriftsartikel (refereegranskat)abstract
- In the centres of stars where the temperature is high enough, three alpha-particles (helium nuclei) are able to combine to form C-12 because of a resonant reaction leading to a nuclear excited state(1). (Stars with masses greater than similar to0.5 times that of the Sun will at some point in their lives have a central temperature high enough for this reaction to proceed.) Although the reaction rate is of critical significance for determining elemental abundances in the Universe(1), and for determining the size of the iron core of a star just before it goes supernova(2), it has hitherto been insufficiently determined(2). Here we report a measurement of the inverse process, where a C-12 nucleus decays to three alpha-particles. We find a dominant resonance at an energy of similar to11 MeV, but do not confirm the presence of a resonance at 9.1 MeV (ref. 3). We show that interference between two resonances has important effects on our measured spectrum. Using these data, we calculate the triple-a rate for temperatures from 10(7) K to 10(10) K and find significant deviations from the standard rates(3). Our rate below similar to5 x 10(7) K is higher than the previous standard, implying that the critical amounts of carbon that catalysed hydrogen burning in the first stars are produced twice as fast as previously believed(4). At temperatures above 10(9) K, our rate is much less, which modifies predicted nucleosynthesis in supernovae(5,6).
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| 25. |
- Grieser, M., et al.
(författare)
-
Storage ring at HIE-ISOLDE
- 2012
-
Ingår i: European Physical Journal: Special Topics. - : Springer Science and Business Media LLC. - 1951-6401 .- 1951-6355. ; 207:1, s. 1-117
-
Tidskriftsartikel (refereegranskat)abstract
- We propose to install a storage ring at an ISOL-type radioactive beam facility for the first time. Specifically, we intend to setup the heavy-ion, low-energy ring TSR at the HIE-ISOLDE facility in CERN, Geneva. Such a facility will provide a capability for experiments with stored secondary beams that is unique in the world. The envisaged physics programme is rich and varied, spanning from investigations of nuclear ground-state properties and reaction studies of astrophysical relevance, to investigations with highly-charged ions and pure isomeric beams. The TSR might also be employed for removal of isobaric contaminants from stored ion beams and for systematic studies within the neutrino beam programme. In addition to experiments performed using beams recirculating within the ring, cooled beams can also be extracted and exploited by external spectrometers for high-precision measurements. The existing TSR, which is presently in operation at the Max-Planck Institute for Nuclear Physics in Heidelberg, is well-suited and can be employed for this purpose. The physics cases as well as technical details of the existing ring facility and of the beam and infrastructure requirements at HIE-ISOLDE are discussed in the present technical design report.
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| 26. |
- Hyldegaard, S., et al.
(författare)
-
Precise branching ratios to unbound 12C states from 12N and 12B [beta]-decays
- 2009
-
Ingår i: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 678:5, s. 459 - 464
-
Tidskriftsartikel (refereegranskat)abstract
- Two complementary experimental techniques have been used to extract precise branching ratios to unbound states in 12C from 12N and 12B [beta]-decays. In the first the three [alpha]-particles emitted after [beta]-decay are measured in coincidence in separate detectors, while in the second method 12N and 12B are implanted in a detector and the summed energy of the three [alpha]-particles is measured directly. For the narrow states at 7.654 MeV (0+) and 12.71 MeV (1+) the resulting branching ratios are both smaller than previous measurements by a factor of [similar, equals]2. The experimental results are compared to no-core shell model calculations with realistic interactions from chiral perturbation theory, and inclusion of three-nucleon forces is found to give improved agreement.
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| 27. |
- Hyldegaard, S., et al.
(författare)
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R-matrix analysis of the beta decays of 12N and 12B
- 2010
-
Ingår i: Physical Review C - Nuclear Physics. - 2469-9985 .- 2469-9993. ; 81:2
-
Tidskriftsartikel (refereegranskat)abstract
- The β decays of 12N and 12B have been studied at KVI and JYFL to resolve the composition of the broad and interfering 0+ and 2+ strengths in the triple-α continuum. For the first time a complete treatment of 3α decay is presented including all major breakup channels. A multilevel, many-channel R-matrix formalism has been developed for the complete description of the breakup in combination with the recently published separate analysis of angular correlations. We find that, in addition to the Hoyle state at 7.65 MeV, more than one 0+ and 2+ state is needed to reproduce the spectra. Broad 03+ and 22+ states are found between 10.5 and 12 MeV in this work. The presence of β strength up to the 12N Q-value window suggests the presence of additional 0+ and 2+ components in the 12C structure at energies above 12.7 MeV.
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| 28. |
- Kudaibergenova, E., et al.
(författare)
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MEASUREMENTS OF THE REACTION CROSS SECTIONS OF NEUTRON-RICH Sn ISOTOPES AT THE R 3 B SETUP
- 2024
-
Ingår i: Acta Physica Polonica B, Proceedings Supplement. - 1899-2358. ; 17:3
-
Tidskriftsartikel (refereegranskat)abstract
- A fundamental framework to describe nuclear matter as a function of pressure and nuclear isospin asymmetry is the nuclear Equation of State (EoS). Constraining the parameters of the EoS is one of the central issues in nuclear physics, especially since the slope parameter L has not yet been constrained well experimentally. It has been identified that a precise determination of the neutron-removal cross section in neutron-rich nuclei, which correlates with the neutron-skin thickness, would provide a more precise constraint on L. To this end, an experiment was performed at the R3B setup in the GSI Helmholtzzentrum für Schwerionenforschung GmbH as a part of the FAIR Phase-0 program. The reactions are studied in inverse kinematics with neutron-rich tin isotopes in the mass range of A = 124–134 on carbon targets of different thicknesses. The reaction products have been measured at beam energies of 400–900 MeV/u in a kinematically complete manner. In this communication, the analysis of124Sn+12C at 900 MeV/u is presented. The charge-exchange reactions, resulting processes, and their role in the calculation of other reaction cross sections are discussed.
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| 29. |
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| 30. |
- Lihtar, I., et al.
(författare)
-
RELATIVISTIC COULOMB EXCITATION OF 124 Sn
- 2024
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Ingår i: Acta Physica Polonica B, Proceedings Supplement. - 1899-2358. ; 17:3
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Tidskriftsartikel (refereegranskat)abstract
- The Coulomb excitation of 124, 128, 130, 132, 134Sn isotopes in the electric field of a Pb target have been studied using the R3B setup as a part of the FAIR Phase-0 program. The experiment was motivated by the possibility of using the nuclear dipole response to infer valuable information on the slope of the symmetry energy of the nuclear equation of state. Measurements were performed in inverse kinematics at relativistic energies of 750 MeV/u and 904 MeV/u. The analysis method and preliminary results for the decay channel with a single outgoing neutron for 124Sn are reported.
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| 31. |
- Ponnath, L., et al.
(författare)
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Measurement of nuclear interaction cross sections towards neutron-skin thickness determination
- 2024
-
Ingår i: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - 0370-2693. ; 855
-
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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| 32. |
- Alcorta, M., et al.
(författare)
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Nuclear Structure of C-12 from Break-up Studies in Complete Kinematics
- 2009
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Ingår i: AIP Conference Proceedings. - : AIP. - 1551-7616 .- 0094-243X. - 9780735407022 ; 1165, s. 27-30 461
-
Konferensbidrag (refereegranskat)abstract
- A complete kinematics study of the B-10(He-3,p alpha alpha alpha) and B-11(He-3,d alpha alpha alpha) reactions has been performed to study the multi-particle break-up of C-12 resonances above the triple-alpha threshold. Four-particle coincidence detection gives us complete information on the direction and energy of the individual alpha particles from the decay of C-12, allowing us to extract new information on the structure of C-12 which we shall present in this contribution. We have observed gamma de-excitation of the T=1 15.11 MeV resonance using charged particle detectors, and have constructed Dalitz plots of the individual resonances in C-12 using the complete kinematics information of the alpha particles which come from their break-up.
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| 33. |
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| 34. |
- Alcorta, M., et al.
(författare)
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Properties of resonances in 12C above the triple-alpha threshold
- 2011
-
Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 312:SECTION 9, s. Art. no. 092013-
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Konferensbidrag (refereegranskat)abstract
- A complete kinematics study of the 10B(3He, pααα) and the 11B(3He, dααα) reactions has been performed to study the multi-particle break-up of 12C resonances above the triple-alpha threshold. The values of energy and widths of some states has been improved, and in states of natural parity partial branches of decay through the ground state of 8Be have been extracted. The influence of the "ghost" of the 8Be ground state has been taken into account in order to clarify the partial branches.
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| 35. |
- Aleksandrov, D., et al.
(författare)
-
Halo excitations in fragmentation of He-6 at 240 MeV/u on carbon and lead targets
- 2000
-
Ingår i: Nuclear Physics A. - 0375-9474. ; 669:1-2, s. 51-64
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Tidskriftsartikel (refereegranskat)abstract
- Dissociation of a 240 MeV/u beam of He-6, incident on carbon and lead targets, has been studied in kinematically complete experiments to investigate low-lying excitation modes in the halo nucleus He-6. It is shown that alignment effects characterize the inelastic scattering and allow an unambiguous assignment of the spin of a narrow resonance observed in the excitation energy spectrum. The differential cross sections for the He-6 inelastic scattering on carbon and lead targets were deduced from the measured moments of the two neutrons and the a-particle. An analysis of these distributions shows that quadrupole and, possibly, monopole excitations characterize the hadronic interaction, while the dipole mode is dominating in Coulomb dissociation. Neither theoretically predicted new resonance states in He-6 nor nuclear excitation of a dipole mode were found. Direct evidence has been obtained for strong suppression of Coulornb post-acceleration in direct Coulomb breakup in a lead target.
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| 36. |
- Aleksandrov, D., et al.
(författare)
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Invariant mass spectrum and alpha-n correlation function studied in the fragmentation of He-6 on a carbon target
- 1998
-
Ingår i: Nuclear Physics A. - 0375-9474. ; 633:2, s. 234-246
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Tidskriftsartikel (refereegranskat)abstract
- Momentum distributions and invariant mass spectra from the breakup of He-6 ions with an energy of 240 MeV/u interacting with a carbon target have been studied. The data were used to extract information about the reaction mechanism which is influenced by the structure of He-6. It is found that the dominant reaction mechanism is a two-step process: knock out of one neutron followed by the decay of the He-5 resonance. The shape of the (alpha+n) two-body invariant mass spectrum is interpreted as mainly reflecting the 5He ground state which is a J(pi) = 3/2(-) resonance. However, no evidence for correlations between cu particles and neutrons is observed in the momentum widths of the distributions. It is demonstrated that a combined analysis of the two-body invariant mass spectrum and an appropriate correlation function may be used to determine the properties of the intermediate resonance. (C) 1998 Elsevier Science B.V.
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| 37. |
- Altstadt, S.G., et al.
(författare)
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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
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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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| 38. |
- Boretzky, K., et al.
(författare)
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NeuLAND: The high-resolution neutron time-of-flight spectrometer for R 3 B at FAIR
- 2021
-
Ingår i: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. - : Elsevier BV. - 0168-9002. ; 1014
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Tidskriftsartikel (refereegranskat)abstract
- NeuLAND (New Large-Area Neutron Detector) is the next-generation neutron detector for the R3B (Reactions with Relativistic Radioactive Beams) experiment at FAIR (Facility for Antiproton and Ion Research). NeuLAND detects neutrons with energies from 100 to 1000 MeV, featuring a high detection efficiency, a high spatial and time resolution, and a large multi-neutron reconstruction efficiency. This is achieved by a highly granular design of organic scintillators: 3000 individual submodules with a size of 5 × 5 × 250 cm3 are arranged in 30 double planes with 100 submodules each, providing an active area of 250 × 250 cm2 and a total depth of 3 m. The spatial resolution due to the granularity together with a time resolution of σt≤ 150 ps ensures high-resolution capabilities. In conjunction with calorimetric properties, a multi-neutron reconstruction efficiency of 50% to 70% for four-neutron events will be achieved, depending on both the emission scenario and the boundary conditions allowed for the reconstruction method. We present in this paper the final design of the detector as well as results from test measurements and simulations on which this design is based.
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| 39. |
- Chulkov, L. V., et al.
(författare)
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Large spin alignment of the unbound He-5 fragment after fragmentation of 240 MeV/nucleon He-6
- 1997
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Ingår i: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 79:2, s. 201-204
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Tidskriftsartikel (refereegranskat)abstract
- Peripheral fragmentation of a 240 MeV/nucleon beam of the halo nucleus He-6 incident on carbon target has been studied in a kinematically complete experiment. It is found that one-neutron stripping to the unbound nucleus He-5 is the dominant fragmentation mechanism and that it leads to a spin alignment of He-5 in a plane perpendicular to the He-5 momentum vector. This is expected to be a common feature for all neutron halo nuclei.
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| 40. |
- Diaz Fernandez, Paloma, 1983, et al.
(författare)
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Quasifree (p, pN) scattering of light neutron-rich nuclei near N=14
- 2018
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Ingår i: Physical Review C. - 2469-9985 .- 2469-9993. ; 97:2
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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.
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| 41. |
- Diget, C. A., et al.
(författare)
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Breakup channels for C-12 triple-alpha continuum states
- 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
- The triple-alpha-particle breakup of states in the triple-alpha continuum of C-12 has been investigated by way of coincident detection of all three alpha particles of the breakup. The states have been fed in the beta decay of N-12 and B-12, and the alpha particles measured using a setup that covers all of the triple-alpha phase space. Contributions from the breakup through the Be-8(0(+)) ground state as well as other channels-interpreted as breakup through excited energies in Be-8-have been identified. Spins and parities of C-12 triple-alpha continuum states are deduced from the measured phase-space distributions for breakup through Be-8 above the ground state by comparison to a fully symmetrized sequential R-matrix description of the breakup. At around 10 MeV in C-12, the breakup is found to be dominated by 0(+) strength breaking up through the ghost of the Be-8(0(+)) ground state with L = 0 angular momentum between the first emitted alpha particle and the intermediate Be-8 nucleus. For C-12 energies above the 12.7 MeV 1(+) state, however, L = 2 breakup of a C-12 2(+) state through the Be-8(2(+)) excited state dominates. Furthermore, the possibility of a 2(+) excited state in the 9-12 MeV region of C-12 is investigated.
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| 42. |
- Diget, C. A., et al.
(författare)
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Properties of the C-12 10 MeV state determined through beta-decay
- 2005
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Ingår i: Nuclear Physics A. - : Elsevier BV. - 0375-9474. ; 760:1-2, s. 3-18
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Tidskriftsartikel (refereegranskat)abstract
- The beta-delayed triple-alpha particle decay of B-12 has been measured with a setup that favours coincidence detection. A broad state in C-12, previously reported around 10 MeV, has been seen and its properties determined through R-matrix analysis of the excitation spectrum. The spin and parity are 0(+). Interference between this state and the Hoyle state at 7.654 MeV has a marked influence on the spectrum. The coupling between the two states makes it difficult to determine the resonance energy. (c) 2005 Elsevier B.V. All rights reserved.
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| 43. |
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| 44. |
- Fynbo, H. O. U., et al.
(författare)
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News on C-12 from beta-decay studies
- 2004
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Ingår i: Nuclear Physics A. - : Elsevier BV. - 0375-9474. ; 738, s. 59-65
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Konferensbidrag (refereegranskat)abstract
- We discuss the importance of the spectroscopic properties of the resonances of C-12 just above the 3alpha-threshold, and review the existing experimental information of this region with emphasis on 0(+) and 2(+) states. A new experimental approach for studying the beta-decays of B-12 and N-12 is presented based on techniques developed in the context of Radioactive beam (rare isotope) physics. Finally preliminary results from an ongoing analysis of two recent experiments are given.
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| 45. |
- Fynbo, H. O. U., et al.
(författare)
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The β-decay approach for studying 12C
- 2008
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Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 111:1
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Tidskriftsartikel (refereegranskat)abstract
- The β-decays of the mirror nuclei 12B and 12N both populate states in 12C and they are therefore a precious source of information about this nucleus. Due to the selection rules of β-decay only 0+, 1+ and 2+ states are populated. This allows a very clean study of unbound states just above the 3α-threshold with those spin and parities. This probe has been applied in two experiments using two complementary experimental techniques: in the first the three α-particles emitted after β-decay are measured in coincidence in separate detectors using the ISOL method, while in the second method 12B and 12N are implanted in a detector and the summed energy of the three α-particles is measured directly. Preliminary results from the two approaches are presented. © 2008 IOP Publishing Ltd.
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| 46. |
- Gobel, K., et al.
(författare)
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Coulomb dissociation of 16O into 4He and 12C
- 2020
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Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 1668:1
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Konferensbidrag (refereegranskat)abstract
- We measured the Coulomb dissociation of 16O into 4He and 12C at the R3B setup in a first campaign within FAIR Phase 0 at GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt. The goal was to improve the accuracy of the experimental data for the 12C(a,?)16O fusion reaction and to reach lower center-ofmass energies than measured so far. The experiment required beam intensities of 109 16O ions per second at an energy of 500 MeV/nucleon. The rare case of Coulomb breakup into 12C and 4He posed another challenge: The magnetic rigidities of the particles are so close because of the same mass-To-charge-number ratio A/Z = 2 for 16O, 12C and 4He. Hence, radical changes of the R3B setup were necessary. All detectors had slits to allow the passage of the unreacted 16O ions, while 4He and 12C would hit the detectors' active areas depending on the scattering angle and their relative energies. We developed and built detectors based on organic scintillators to track and identify the reaction products with sufficient precision.
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| 47. |
- Heine, M., et al.
(författare)
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Determination of the neutron-capture rate of C-17 for r-process nucleosynthesis
- 2017
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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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| 48. |
- Herrera, I., et al.
(författare)
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Applying resilience concepts in crisis management and critical infrastructures-the DARWIN project
- 2017
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Ingår i: RISK, RELIABILITY AND SAFETY: INNOVATING THEORY AND PRACTICE. - : CRC PRESS. - 9781315374987 - 9781138029972 ; , s. 2137-2144
-
Konferensbidrag (refereegranskat)abstract
- Recent crises and disasters, both natural and man-made have led to the conclusion that there is a need for a resilient approach to preparing for and dealing with such events is needed. In this context, the DARWIN project aims to improve response to expected and unexpected crises affecting critical infrastructures and social structures by developing management guidelines on resilience concepts and innovative training modules for crisis management. The guidelines will cover essential resilience abilities of stakeholders to anticipate, monitor, respond, adapt, learn and evolve, to ensure efficient operation in face of crises. This paper uses a selection of resilience concepts to illustrate how resilience management guidelines can be used to understand and improve crises management. The application of the concepts to this specific case is an experiment to guide further work. This experiment shows that resilience guidelines should enable discovery on how multiple actors operate in a flexible manner and adapt in rapidly changing environment. Further work, needs to specify a set of guidelines co-developed and tested with end-users.
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| 49. |
- Hoff, P, et al.
(författare)
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Nuclear spectroscopy at Sn-133
- 2000
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Ingår i: HYPERFINE INTERACTIONS. - : BALTZER SCI PUBL BV. - 0304-3843. ; 129:1-4, s. 141-148
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- It is described how the measurement of n gamma -coincidences can be used to identify single-particle states in Sn-133. This method, in combination with the improved yields at ISOLDE, has facilitated firm determination of three excited single-particle stat
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| 50. |
- Humbert, F., et al.
(författare)
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Longitudinal and Transverse-Momentum Distributions of Li-9 Fragments from Break-up of Li-11
- 1995
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Ingår i: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - 0370-2693. ; 347:3-4, s. 198-204
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Tidskriftsartikel (refereegranskat)abstract
- Transverse and longitudinal momentum distributions of Li-9 fragments from Li-11 break-up reactions in C, Al and Pb targets have been measured at 280 MeV/u. The two-neutron removal cross-section was measured to be sigma(-2n), = 0.26 +/- 0.02 b for the carbon target, sigma(-2n) = 0.47 +/- 0.08 b for the aluminum target and sigma(-2n), = 1.9 +/- 0.4 b for the lead target. No significant difference is observed between the narrow widths (FWHM approximate to 47 MeV/c) of the transverse and longitudinal momentum distributions of the Li-9 fragments. The physical implications of this are discussed.
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