1. |
- Grieser, M., et al.
(author)
-
Storage ring at HIE-ISOLDE Technical design report
- 2012
-
In: The European Physical Journal Special Topics. - : Springer Science and Business Media LLC. - 1951-6355 .- 1951-6401. ; 207:1, s. 1-117
-
Research review (peer-reviewed)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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2. |
- Kattge, Jens, et al.
(author)
-
TRY plant trait database - enhanced coverage and open access
- 2020
-
In: Global Change Biology. - : Wiley-Blackwell. - 1354-1013 .- 1365-2486. ; 26:1, s. 119-188
-
Journal article (peer-reviewed)abstract
- Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives.
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3. |
- MacDougall, Andrew S., et al.
(author)
-
Widening global variability in grassland biomass since the 1980s
- 2024
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In: Nature Ecology & Evolution. - : Springer Nature. - 2397-334X.
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Journal article (peer-reviewed)abstract
- Global change is associated with variable shifts in the annual production of aboveground plant biomass, suggesting localized sensitivities with unclear causal origins. Combining remotely sensed normalized difference vegetation index data since the 1980s with contemporary field data from 84 grasslands on 6 continents, we show a widening divergence in site-level biomass ranging from +51% to −34% globally. Biomass generally increased in warmer, wetter and species-rich sites with longer growing seasons and declined in species-poor arid areas. Phenological changes were widespread, revealing substantive transitions in grassland seasonal cycling. Grazing, nitrogen deposition and plant invasion were prevalent in some regions but did not predict overall trends. Grasslands are undergoing sizable changes in production, with implications for food security, biodiversity and carbon storage especially in arid regions where declines are accelerating.
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4. |
- Caceres, L. S., et al.
(author)
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Identification of Excited States in the N = Z Nucleus 82Nb
- 2007
-
In: Acta Physica Polonica. Series B: Elementary Particle Physics, Nuclear Physics, Statistical Physics, Theory of Relativity, Field Theory. - 0587-4254. ; 38:4, s. 1271-1275
-
Journal article (peer-reviewed)abstract
- Information on the first excited states in the N = Z = 41 nucleus Nb-82 sheds light on the competition of isospin T = 0 and T = 1 states in the A similar to 80 region. The measurement was performed at the GSI laboratory using fragmentation of a Ag-107 primary beam at 750 MeV/u on a 4 g/cm(2) Be-9 target. The fragments were separated and identified unambiguously in the FRagment Separator. Three excited states were observed and the half-life estimate for the isomeric state was extracted. A tentative spin assignment based on the isobaric analogue states systematics in the T-z = 1 nucleus Zr-82, and transition probabilities indicate T = 1 character of the first two excited states, and T = 0 for the isomeric state.
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5. |
- Falster, Daniel, et al.
(author)
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AusTraits, a curated plant trait database for the Australian flora
- 2021
-
In: Scientific Data. - : Nature Portfolio. - 2052-4463. ; 8:1
-
Journal article (peer-reviewed)abstract
- We introduce the AusTraits database - a compilation of values of plant traits for taxa in the Australian flora (hereafter AusTraits). AusTraits synthesises data on 448 traits across 28,640 taxa from field campaigns, published literature, taxonomic monographs, and individual taxon descriptions. Traits vary in scope from physiological measures of performance (e.g. photosynthetic gas exchange, water-use efficiency) to morphological attributes (e.g. leaf area, seed mass, plant height) which link to aspects of ecological variation. AusTraits contains curated and harmonised individual- and species-level measurements coupled to, where available, contextual information on site properties and experimental conditions. This article provides information on version 3.0.2 of AusTraits which contains data for 997,808 trait-by-taxon combinations. We envision AusTraits as an ongoing collaborative initiative for easily archiving and sharing trait data, which also provides a template for other national or regional initiatives globally to fill persistent gaps in trait knowledge.
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6. |
- Farrelly, G. F., et al.
(author)
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Revision of the K-Isomer in 190W
- 2009
-
In: Acta Physica Polonica. Series B: Elementary Particle Physics, Nuclear Physics, Statistical Physics, Theory of Relativity, Field Theory. - 0587-4254. ; 40:3, s. 885-888
-
Journal article (peer-reviewed)abstract
- Gamma rays from the decay of an isomer in W-190(116) have been observed following projectile fragmentation of a 1 GeV per nucleon Pb-208 beam. An earlier experiment indicated decay from a (10(-)) isomer to the ground state rotational band. Improved statistics have enabled gamma coincidence and time-difference measurements to be made which alter the previous interpretation. Blocked BCS calculations have also been used together with reduced hindrance factors to indicate possible values of spin-parity for the isomer.
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7. |
- Garnsworthy, A. B., et al.
(author)
-
Isomeric States in Neutron-deficient A~80-90 Nuclei Populated in the Fragmentation of 107Ag
- 2009
-
In: Physical Review C (Nuclear Physics). - 0556-2813. ; 80:6
-
Journal article (peer-reviewed)abstract
- The relativistic projectile fragmentation of a 750 MeV per nucleon beam of Ag-107 was used to populate isomeric states in neutron-deficient nuclei around A=80-90. Reaction products were separated and unambiguously identified using the GSI FRagment Separator (FRS) and its ancillary detectors. At the final focal plane, the fragments were slowed from relativistic energies by means of an aluminium degrader and implanted in a passive stopper in the center of the high-efficiency, high-granularity Stopped Rare Isotope Spectroscopic INvestigation at GSI (RISING) germanium array. This allowed the identification of excited states in the N=Z nuclei Tc-86(43) and, for the first time, Nb-82(41). Isomeric states have also been identified for the first time in Tc-87,Tc-88, and a previously unreported isomer was observed in Nb-84. Experimental results are presented along with a discussion on the structure of these nuclei based on interpretations provided by several theoretical models.
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8. |
- Garnsworthy, A. B., et al.
(author)
-
Isomeric States in the Light Tc Isotopes
- 2007
-
In: Acta Physica Polonica. Series B: Elementary Particle Physics, Nuclear Physics, Statistical Physics, Theory of Relativity, Field Theory. - 0587-4254. ; 38:4, s. 1265-1269
-
Journal article (peer-reviewed)abstract
- Preliminary results from the first experiment of the Stopped Beam RISING campaign are presented. The relativistic projectile fragmentation of a 750 MeV/u beam of Ag-107 populated isomeric states in very neutron deficient nuclei at the proton dripline around mass 80-90. Nuclei were unambiguously identified using the FRagment Separator (FRS) and its ancillary detectors located at GSI. The ions produced were slowed down from relativistic energies by means of an Al degrader and implanted in the centre of the high-efficiency Stopped RISING array. This allowed the identification of new excited states in the N = Z = 43 nucleus, Tc-86, populated following the de-excitation of a microsecond isomer. Preliminary results of this analysis, as well as previously unobserved isomeric states in Tc-87,Tc-88. are reported.
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9. |
- Garnsworthy, A B, et al.
(author)
-
Neutron-proton pairing competition in N = Z nuclei: Metastable state decays in the proton dripline nuclei Nb-82(41) and Tc-86(43)
- 2008
-
In: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 660:4, s. 326-330
-
Journal article (peer-reviewed)abstract
- The low-lying structures of the self-conjugate (N = Z) nuclei Nb-82(41)41 and Tc-86(43)43 have been investigated using isomeric-decay spectroscopy following the projectile fragmentation of a Ag-107 beam. These represent the heaviest odd-odd N = Z nuclei in which internal decays have been identified to date. The resulting level schemes shed light on the shape evolution along the N = Z line between the doubly-magic systems Ni-56(28) and Sn-100(50) and support a preference for T = 1 states in T-z = 0 odd-odd nuclei at low excitation energies associated with a T = 1 neutron-proton pairing gap. Comparison with Projected Shell Model calculations suggests that the decay in Nb-82 may be interpreted as an isospin-changing K isomer.
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10. |
- Myalski, S., et al.
(author)
-
Isomeric Ratio for the I=8+ Yrast State in 96Pd Produced in the Relativistic Fragmentation of 107Ag
- 2007
-
In: Acta Physica Polonica. Series B: Elementary Particle Physics, Nuclear Physics, Statistical Physics, Theory of Relativity, Field Theory. - 0587-4254. ; 38:4, s. 1277-1282
-
Journal article (peer-reviewed)abstract
- We report on the preliminary results from a study of the decay of the I-pi = 8(+) T-1/2 = 2 mu s isomer in Pd-96 performed as part of the Stopped-Beam RISING campaign within the Rare Isotope Investigation at GSI (RISING). The Pd-96 ions were produced following the projectile fragmentation of a 750 MeV per nucleon Ag-107 primary beam. The reaction products were separated and identified by the in-flight method using the GSI Fragment Separator. The residues of interest were stopped in a perspex stopper surrounded by an array of 15, seven-element germanium Cluster detectors. One of the goals of the current work is to investigate the population of high-spin states produced projectile fragmentation reactions using isomeric ratio measurements to infer information on the angular momentum population distribution. In this short contribution the method and results of determining the isomeric ratio for the I-pi = 8(+) microsecond isomer in Pd-96 nucleus are presented.
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11. |
- Myalski, S., et al.
(author)
-
Isomeric Ratios For Nuclei With Z=62-67 And A=142-152 Produced In The Relativistic Fragmentation Of Pb-208
- 2009
-
In: Acta Physica Polonica. Series B: Elementary Particle Physics, Nuclear Physics, Statistical Physics, Theory of Relativity, Field Theory. - 0587-4254. ; 40:3, s. 879-883
-
Journal article (peer-reviewed)abstract
- Isomeric states in nuclei with Z = 62-67 and A = 142-152 produced in the fragmentation of the relativistic (1 GeV/nucleon) Pb-208 beam were investigated. Isomeric ratios were determined for 10 isomeric states. Significant differences between theoretical and experimental values were observed.
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12. |
- Myalski, S., et al.
(author)
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Study of Isomer Production Rates for A=142-152 and Z=62-67 in Fragmentation of a Relativistic 208Pb Beam
- 2012
-
In: Acta Physica Polonica. Series B: Elementary Particle Physics, Nuclear Physics, Statistical Physics, Theory of Relativity, Field Theory. - 0587-4254. ; 43:2, s. 253-259
-
Journal article (peer-reviewed)abstract
- We have investigated nuclear fragmentation reactions of a relativistic Pb-208 beam. Ten isomeric states for nuclei with A = 142-152 and Z = 62-67 were observed. Measured isomeric ratios were compared, together with values from other experiments, with prediction of theoretical models. The discrepancies between the experimental and theoretical values were discussed in terms of transitions by-passing the isomer that are not included in the models.
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13. |
- Pietri, S., et al.
(author)
-
First Results from the Stopped Beam Isomer RISING Campaign at GSI
- 2007
-
In: Acta Physica Polonica. Series B: Elementary Particle Physics, Nuclear Physics, Statistical Physics, Theory of Relativity, Field Theory. - 0587-4254. ; 38:4, s. 1255-1264
-
Journal article (peer-reviewed)abstract
- The first results from a series of experiments focused on the study of the internal structure of nuclei at the extremes of N:Z ratio using isomer spectroscopy are reported. These experiments represent the first of the Stopped Beam section of the Rare Isotopes Investigations at GSI (RISING) project. Exotic nuclei were synthesized using relativistic projectile fragmentation of similar to 500 -> 1000 MeV/u beams of Ag-107, Pb-208, Xe-136 and Ni-58, or fission of 750 MeV/u U-238 provided by the SIS synchrotron at GSI. A detailed description of the RISING stopped beam set up is given, together with a report of the performance of the associated gamma-ray spectrometer array. Selected results of the first experimental campaign are presented together with a discussion on the use of isomeric spectroscopy to study GeV range nuclear fragmentation. Details on future research plans of this collaboration are also outlined.
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14. |
- Podolyak, Zs., et al.
(author)
-
Isomeric Decay Studies Around 204Pt and 148Tb
- 2007
-
In: The European Physical Journal. Special Topics. - : Springer Science and Business Media LLC. - 1951-6355 .- 1951-6401. ; 150, s. 165-168
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Journal article (peer-reviewed)abstract
- Relativistic energy projectile fragmentation of Pb-208 has been used to produce a range of exotic nuclei. The nuclei of interest were studied by detecting delayed gamma rays following the decay of isomeric states. Experimental information on the excited states of the neutron-rich N = 126 nucleus, Pt-204, following internal decay of two isomeric states, was obtained for the first time. In addition, decays from the previously reported isomeric I=27h and I=(49/2)h states in Tb-148 and Gd-147, respectively, have been observed. These isomeric decays represent the highest spin discrete states observed to date following a projectile fragmentation reaction, and opens further the possibility of doing 'high-spin physics' using this technique.
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15. |
- Podolyak, Zs., et al.
(author)
-
Structure of Neutron-rich Nuclei Around the N=126 Closed Shell; the Yrast Structure of 205Au up to Spin-parity I = (19/2+)
- 2009
-
In: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-6001 .- 1434-601X. ; 42:3, s. 489-493
-
Conference paper (peer-reviewed)abstract
- Heavy neutron-rich nuclei have been populated through the relativistic fragmentation of a Pb-208(82) beam at E/A = 1 GeV on a 2.5 g/cm(2) thick Be target. The synthesised nuclei were selected and identified in-flight using the fragment separator at GSI. Approximately 300 ns after production, the selected nuclei were implanted in an similar to 8 mm thick perspex stopper, positioned at the centre of the RISING gamma-ray detector spectrometer array. A previously unreported isomer with a half-life T-1/2 = 163(5) ns has been observed in the N = 126 closed-shell nucleus Au-205(79). Through gamma-ray singles and gamma-gamma coincidence analysis a level scheme was established. The comparison with a shell model calculation tentatively identifies the spin-parity of the excited states, including the isomer itself, which is found to be I-pi = (19/2(+)).
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16. |
- Podolyak, Zs., et al.
(author)
-
Weakly Deformed Oblate Structures in 198Os
- 2009
-
In: Physical Review C (Nuclear Physics). - 0556-2813. ; 79:3
-
Journal article (peer-reviewed)abstract
- Gamma rays de-exciting isomeric states in the neutron-rich nucleus Os-198(76)122 have been observed following relativistic projectile fragmentation of a 1 GeV per nucleon Pb-208 beam. The ground-state band has properties compatible with oblate deformation. The evolution of the structure of Os isotopes characterized by sudden prolate-oblate shape change is discussed and contrasted with the smooth change known in the Pt chain.
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17. |
- Regan, P. H., et al.
(author)
-
First Results from the Stopped RISING Campaign at GSI: The Mapping of Isomeric Decays in Highly Exotic Nuclei
- 2007
-
In: AIP Conference Proceedings. - : AIP. - 0094-243X. - 9780735413283 ; 899, s. 19-22
-
Conference paper (peer-reviewed)abstract
- The first results from the Stopped Beam RISING experimental campaign performed at the GSI laboratory in Darmstadt, Germany, are presented. RISING (Rare ISotope INvestigations at GSI) constitutes a major new experimental program in European nuclear structure physics research aimed at using relativistic‐energy, projectile‐fragmentation reactions to study nuclei with exotic proton‐to‐neutron ratios. This paper introduces the physics aims of the Stopped RISING collaboration and presents some technical details and initial results from experiments using the RISING array to study decays from metastable nuclear states in both proton and neutron‐rich nuclei.
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18. |
- Rudolph, Dirk, et al.
(author)
-
Exciting Isomers from the First Stopped-beam RISING Campaign
- 2007
-
In: The European Physical Journal. Special Topics. - : Springer Science and Business Media LLC. - 1951-6355 .- 1951-6401. ; 150, s. 173-176
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Journal article (peer-reviewed)abstract
- First results are reported from a major new initiative of experiments, which focus on nuclear structure studies at extreme isospin values by means of isomer spectroscopy. The experiments represent the first part of the so-called stopped-beam campaign within the Rare ISotope INvestigations at GSI (RISING) project. Time-correlated gamma decays from individually identified nuclear species have been measured, allowing the clean identification of isomeric decays in a wide range of exotic nuclei both at the proton drip-line and in heavy, neutron-rich systems. An overview of the experimental technique will be given, together with the performance of the new germanium detector array and future research plans for the collaboration.
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19. |
- Steer, S. J., et al.
(author)
-
Isomeric Decay Studies In Neutron-Rich N Approximate To 126 Nuclei
- 2009
-
In: International Journal Of Modern Physics E-Nuclear Physics. - 0218-3013. ; 18:4, s. 1002-1007
-
Conference paper (peer-reviewed)abstract
- Heavy neutron-rich nuclei were populated via relativistic energy fragmentation of a E/A= 1 GeV Pb-208 beam. The nuclei of interest were selected and identified by a fragment separator and then implanted in a passive plastic stopper. Delayed. rays following internal isomeric decays were detected by the RISING array. Experimental information was obtained on a number of nuclei with Z=73-80 (Ta-Hg), providing new information both on the prolate-oblate transitional region as well as on the N=126 closed shell nuclei.
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20. |
- Steer, S. J., et al.
(author)
-
Isomeric States Observed in Heavy Neutron-rich Nuclei Populated in the Fragmentation of a 208Pb Beam
- 2011
-
In: Physical Review C (Nuclear Physics). - 0556-2813. ; 84:4
-
Journal article (peer-reviewed)abstract
- Heavy neutron-rich nuclei were populated via the fragmentation of a E/A = 1 GeV Pb-208(82) beam. Secondary fragments were separated and identified and subsequently implanted in a passive stopper. By the detection of delayed gamma rays, isomeric decays associated with these nuclei have been identified. A total of 49 isomers were detected, with the majority of them observed for the first time. The newly discovered isomers are in Hg-204,205(80), Au-201,202,204,205(79), Pt-197,203,204(78), Ir-195,199-203(77), Os-193,197-199(76), Re-196(75), W-190,191(74), and Ta-189(73). Possible level schemes are constructed and the structure of the nuclei discussed. To aid the interpretation, shell-model as well as BCS calculations were performed.
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21. |
- Steer, S. J., et al.
(author)
-
Single-particle Behavior at N=126: Isomeric Decays in Neutron-rich 204Pt
- 2008
-
In: Physical Review C (Nuclear Physics). - 0556-2813. ; 78:6
-
Journal article (peer-reviewed)abstract
- The four proton-hole nucleus Pt-204 was populated in the fragmentation of an E/A = 1 GeV Pb-208 beam. The yrast structure of Pt-204 has been observed up to angular momentum I = 10h by detecting delayed gamma-ray transitions originating from metastable states. These long-lived excited states have been identified to have spin-parities of I-pi = (10(+)), (7(-)), and (5(-)) and half-lives of T-1/2 = 146(14) ns, 55(3) mu s, and 5.5(7) mu s, respectively. The structure of the magic N = 126 Pt-204 nucleus is discussed and understood in terms of the spherical shell model. The data suggest a revision of the two-body interaction for N = 126, Z < 82, which determines the evolution of nuclear structure toward the r-process waiting point nuclei.
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22. |
- Grieser, M., et al.
(author)
-
Storage ring at HIE-ISOLDE
- 2012
-
In: European Physical Journal: Special Topics. - : Springer Science and Business Media LLC. - 1951-6401 .- 1951-6355. ; 207:1, s. 1-117
-
Journal article (peer-reviewed)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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23. |
- Jentschel, M., et al.
(author)
-
EXILL - a high-efficiency, high-resolution setup for gamma-spectroscopy at an intense cold neutron beam facility
- 2017
-
In: Journal of Instrumentation. - : IOP PUBLISHING LTD. - 1748-0221. ; 12
-
Journal article (peer-reviewed)abstract
- In the EXILL campaign a highly efficient array of high purity germanium (HPGe) detectors was operated at the cold neutron beam facility PF1B of the Institut Laue-Langevin (ILL) to carry out nuclear structure studies, via measurements of gamma-rays following neutron-induced capture and fission reactions. The setup consisted of a collimation system producing a pencil beam with a thermal capture equivalent flux of about 10(8) ns(-1)cm(2) at the target position and negligible neutron halo. The targetwas surrounded by an array of eight to ten anti-Compton shielded EXOGAMClover detectors, four to six anti-Compton shielded large coaxial GASP detectors and two standard Clover detectors. For a part of the campaign the array was combined with 16 LaBr3:(Ce) detectors from the FATIMA collaboration. The detectorswere arranged in an array of rhombicuboctahedron geometry, providing the possibility to carry out very precise angular correlation and directional-polarization correlation measurements. The triggerless acquisition system allowed a signal collection rate of up to 6 x 10(5) Hz. The data allowed to set multi-fold coincidences to obtain decay schemes and in combination with the FATIMA array of LaBr3:(Ce) detectors to analyze half-lives of excited levels in the pico-to microsecond range. Precise energy and efficiency calibrations of EXILL were performed using standard calibration sources of Ba-133, Co-60 and Eu-152 as well as data from the reactions Al-27(n, gamma)Al-28 and Cl-35(n,gamma)Cl-36 in the energy range from 30 keV up to 10MeV.
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24. |
- Reifarth, R., et al.
(author)
-
Nuclear astrophysics with radioactive ions at FAIR
- 2016
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In: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 665:1
-
Conference paper (peer-reviewed)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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25. |
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26. |
- Söderström, Pär-Anders, et al.
(author)
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Spectroscopy of neutron-rich Dy-168,Dy-170 : Yrast band evolution close to the NpNn valence maximum
- 2010
-
In: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 81:3, s. 034310-
-
Journal article (peer-reviewed)abstract
- The yrast sequence of the neutron-rich dysprosium isotope Dy-168 has been studied using multinucleon transfer reactions following collisions between a 460-MeV Se-82 beam and an Er-170 target. The reaction products were identified using the PRISMA magnetic spectrometer and the gamma rays detected using the CLARA HPGe-detector array. The 2(+) and 4(+) members of the previously measured ground-state rotational band of Dy-168 have been confirmed and the yrast band extended up to 10(+). A tentative candidate for the 4(+) -> 2(+) transition in Dy-170 was also identified. The data on these nuclei and on the lighter even-even dysprosium isotopes are interpreted in terms of total Routhian surface calculations and the evolution of collectivity in the vicinity of the proton-neutron valence product maximum is discussed.
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27. |
- Altstadt, S.G., et al.
(author)
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B-13,B-14(n,gamma) via Coulomb Dissociation for Nucleosynthesis towards the r-Process
- 2014
-
In: Nuclear Data Sheets. - : Elsevier BV. - 1095-9904 .- 0090-3752. ; 120, s. 197-200
-
Conference paper (peer-reviewed)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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28. |
- Antonov, A. N., et al.
(author)
-
The electron-ion scattering experiment ELISe at the International Facility for Antiproton and Ion Research (FAIR)-A conceptual design study
- 2011
-
In: 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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Journal article (peer-reviewed)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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29. |
- Assié, M., et al.
(author)
-
Neutron correlations in 6He viewed through nuclear break-up
- 2009
-
In: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-6001 .- 1434-601X. ; 42:3, s. 441-446
-
Journal article (peer-reviewed)abstract
- The nuclear break-up of He-6 on a Pb-208 target was studied at 20 A MeV using a secondary beam of He-6 produced by the SPIRAL facility at GANIL. alpha-particles were detected in coincidence with two neutrons with a large angular coverage and the reaction mechanism was identified. From the distribution of the relative angles between the two neutrons the correlation function was extracted. It shows a strong correlation at small relative angles attributed to the contribution of the di-neutron configuration of He-6.
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30. |
- Assie, M., et al.
(author)
-
Neutron correlations in 6He viewed through nuclear break-up
- 2010
-
In: Modern Physics Letters A. - 0217-7323 .- 1793-6632. ; 25:21-23, s. 1846-1849
-
Journal article (peer-reviewed)abstract
- Nuclear break-up as a tool to study neutron correlations is investigated both theoretically and experimentally. First a time dependent theory going beyond mean field has been developed and shows that correlations between nucleons can be probed through nuclear break-up. Secondly, nuclear break-up of He-6 on Pb-208 target was studied at 20 A.MeV using a secondary beam of He-6 produced by the SPIRAL facility at GANIL. From the correlation function, a strong contribution of the di-neutron configuration of He-6 is found.
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31. |
- Atar, L., et al.
(author)
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Quasifree (p, 2p) Reactions on Oxygen Isotopes: Observation of Isospin Independence of the Reduced Single-Particle Strength
- 2018
-
In: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 120:5
-
Journal article (peer-reviewed)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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32. |
- Bhattacharyya, A., et al.
(author)
-
Neutron capture cross sections of light neutron-rich nuclei relevant for -process nucleosynthesis
- 2021
-
In: Physical Review C. - 2469-9993 .- 2469-9985. ; 104:4
-
Journal article (peer-reviewed)abstract
- The measurements of neutron capture cross sections of neutron-rich nuclei are challenging but essential for understanding nucleosynthesis and stellar evolution processes in the explosive burning scenario. In the quest of -process abundances, according to the neutrino-driven-wind model, light neutron-rich unstable nuclei may play a significant role as seed nuclei that influence the abundance pattern. Hence, experimental data for neutron capture cross sections of neutron-rich nuclei are needed. Coulomb dissociation of radioactive ion beams at intermediate energy is a powerful indirect method for inferring capture cross section. As a test case for validation of the indirect method, the neutron capture cross section (, ) for was inferred from the Coulomb dissociation of at intermediate energy ( MeV). A comparison between different theoretical approaches and experimental results for the reaction is discussed. We report for the first time experimental reaction cross sections of , , , and . The reaction cross sections were inferred indirectly through Coulomb dissociation of , , and at incident projectile energies around 400-430 MeV using the FRS-LAND setup at GSI, Darmstadt. The neutron capture cross sections were obtained from the photoabsorption cross sections with the aid of the detailed balance theorem. The reaction rates for the neutron-rich Na, Mg, Al nuclei at typical -process temperatures were obtained from the measured () capture cross sections. The measured neutron capture reaction rates of the neutron-rich nuclei, , , and are significantly lower than those predicted by the Hauser-Feshbach decay model. A similar trend was observed earlier for and but in the case of the trend is opposite. The situation is more complicated when the ground state has a multi-particle-hole configuration. For , the measured cross section is about higher than the Hauser-Feshbach prediction.
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33. |
- Boillos, J. M., et al.
(author)
-
Isotopic cross sections of fragmentation residues produced by light projectiles on carbon near
- 2022
-
In: Physical Review C. - 2469-9993 .- 2469-9985. ; 105:1
-
Journal article (peer-reviewed)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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34. |
- Caesar, C., et al.
(author)
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Beyond the neutron drip line: The unbound oxygen isotopes O-25 and O-26
- 2013
-
In: Physical Review C - Nuclear Physics. - 2469-9985 .- 2469-9993 .- 0556-2813. ; 88:3
-
Journal article (peer-reviewed)abstract
- The very neutron-rich oxygen isotopes O-25 and O-26 are investigated experimentally and theoretically. The unbound states are populated in an experiment performed at the R3B-LAND setup at GSI via proton-knockout reactions from F-26 and F-27 at relativistic energies around 442 and 414 MeV/nucleon, respectively. From the kinematically complete measurement of the decay into O-24 plus one or two neutrons, the O-25 ground-state energy and width are determined, and upper limits for the O-26 ground-state energy and lifetime are extracted. In addition, the results provide indications for an excited state in O-26 at around 4 MeV. The experimental findings are compared to theoretical shell-model calculations based on chiral two- and three-nucleon (3N) forces, including for the first time residual 3N forces, which are shown to be amplified as valence neutrons are added.
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35. |
- Chakraborty, S., et al.
(author)
-
Ground-state configuration of neutron-rich Al-35 via Coulomb breakup
- 2017
-
In: Physical Review C. - 2469-9985 .- 2469-9993. ; 96:3, s. 1965-
-
Journal article (peer-reviewed)abstract
- The ground-state configuration of Al-35 has been studied via Coulomb dissociation (CD) using the LAND-FRS setup (GSI, Darmstadt) at a relativistic energy of similar to 403 MeV/nucleon. The measured inclusive differential CD cross section for Al-35, integrated up to 5.0 MeV relative energy between the Al-34 core and the neutron using a Pb target, is 78(13) mb. The exclusive measured CD cross section that populates various excited states of 34Al is 29(7) mb. The differential CD cross section of Al-35 -> Al-34 + n has been interpreted in the light of a direct breakup model, and it suggests that the possible ground-state spin and parity of Al-35 could be, tentatively, 1/2+ or 3/2(+) or 5/2(+). The valence neutrons, in the ground state of Al-35, may occupy a combination of either l = 3,0 or l = 1,2 orbitals coupled with the Al-34 core in the ground and isomeric state(s), respectively. This hints of a particle-hole configuration of the neutron across the magic shell gaps at N = 20,28 which suggests narrowing the magic shell gap. If the 5/2+ is the ground-state spin-parity of Al-35 as suggested in the literature, then the major ground-state configuration of Al-35 is a combination of Al-34(g. s.; 4(-)) circle times upsilon(p3/2) and Al-34(isomer; 1(+)) circle times upsilon(d3/2) states. The result from this experiment has been compared with that from a previous knockout measurement and a calculation using the SDPF-M interaction.
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36. |
- Chakraborty, S., et al.
(author)
-
Ground-state configuration of neutron-rich Aluminum isotopes through Coulomb breakup
- 2014
-
In: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 66
-
Conference paper (peer-reviewed)abstract
- Neutron-rich 34,35Al isotopes have been studied through Coulomb excitation using LAND-FRS setup at GSI, Darmstadt. The method of invariant mass analysis has been used to reconstruct the excitation energy of the nucleus prior to decay. Comparison of experimental CD cross-section with direct breakup model calculation with neutron in p3/2 orbital favours 34Al(g.s) - νp3/2 as ground state configuration of 35Al. But ground state configuration of 34Al is complicated as evident from γ-ray spectra of 33Al after Coulomb breakup of 34Al. © Owned by the authors, published by EDP Sciences, 2014.
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37. |
- Datta, U., et al.
(author)
-
Direct experimental evidence for a multiparticle-hole ground state configuration of deformed Mg-33
- 2016
-
In: Physical Review C. - 2469-9985 .- 2469-9993. ; 94:3
-
Journal article (peer-reviewed)abstract
- The first direct experimental evidence of a multiparticle-hole ground state configuration of the neutron-rich Mg-33 isotope has been obtained via intermediate energy (400 A MeV) Coulomb dissociation measurement. The major part similar to(70 +/- 13)% of the cross section is observed to populate the excited states of Mg-32 after the Coulomb breakup of Mg-33. The shapes of the differential Coulomb dissociation cross sections in coincidence with different core excited states favor that the valence neutron occupies both the s(1/2) and p(3/2) orbitals. These experimental findings suggest a significant reduction and merging of sd-pf shell gaps at N similar to 20 and 28. The ground state configuration of Mg-33 is predominantly a combination of Mg-32(3.0,3.5MeV; 2(-), 1(-)) circle times nu(s1/2), Mg-32(2.5MeV; 2(+)) circle times nu(p3/2), and Mg-32(0; 0(+)) circle times nu(p3/2). The experimentally obtained quantitative spectroscopic information for the valence neutron occupation of the s and p orbitals, coupled with different core states, is in agreement with Monte Carlo shell model (MCSM) calculation using 3 MeV as the shell gap at N = 20.
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38. |
- Diaz Fernandez, Paloma, 1983, et al.
(author)
-
Quasifree (p, pN) scattering of light neutron-rich nuclei near N=14
- 2018
-
In: Physical Review C. - 2469-9985 .- 2469-9993. ; 97:2
-
Journal article (peer-reviewed)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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39. |
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40. |
- Garnsworthy, A. B., et al.
(author)
-
Spectroscopy of Po-212 and At-213 using a He-8 radioactive beam and EXOGAM
- 2005
-
In: Journal of Physics G. - : IOP Publishing. - 0954-3899 .- 1361-6471. ; 31:10, s. S1851-S1854
-
Journal article (peer-reviewed)abstract
- A beam of 28 MeV He-8 particles with an average intensity 2 x 10(5) ions s(-1), produced by the SPIRAL facility at GANIL, was used to initiate fusion-evaporation reactions in thick targets of Pb-201 and Bi-209. Excited states of Po-212 and At-213 were populated in (He-8,4n) reactions. The emitted gamma-rays were detected using the EXOGAM array composed of four Compton suppressed germanium Clover detectors in a close geometry configuration. Preliminary results show that Po-212 has been populated to high spin (I similar or equal to 14) with a significantly increased yield compared with our previous He-8 beam experiment. An apparently increased relative population of states up to 12(+) was observed compared with published results from a Pb-208(Be-9,alpha n)(212) Po reaction at 48 MeV. Evidence is presented for a previously unreported de-excitation pathway: 69 keV (13(-) -> 12(+)). States up to I-pi = (39/2(-)) have also been observed in At-213.
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41. |
- Heine, M., et al.
(author)
-
Determination of the neutron-capture rate of C-17 for r-process nucleosynthesis
- 2017
-
In: Physical Review C. - 2469-9985 .- 2469-9993. ; 95:1, s. Article no 014613 -
-
Journal article (peer-reviewed)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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42. |
- Holl, M., et al.
(author)
-
Quasi-free neutron and proton knockout reactions from light nuclei in a wide neutron-to-proton asymmetry range
- 2019
-
In: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 795, s. 682-688
-
Journal article (peer-reviewed)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.
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43. |
- Marques, F. M., et al.
(author)
-
Neutrons from the breakup of C-19
- 1996
-
In: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - 0370-2693. ; 381:4, s. 407-412
-
Journal article (peer-reviewed)abstract
- Neutrons arising from the breakup of a 30 MeV/nucleon C-19 beam on a tantalum target have been measured using the 98 element array DEMON. A narrow, forward peaked neutron angular distribution, with a corresponding momentum spread considerably smaller than those measured simultaneously for N-21, O-22 and F-24 was observed for charged fragments with Z
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44. |
- Martel, I., et al.
(author)
-
An innovative Superconducting Recoil Separator for HIE-ISOLDE
- 2023
-
In: Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms. - : ELSEVIER. - 0168-583X .- 1872-9584. ; 541, s. 176-179
-
Journal article (peer-reviewed)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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45. |
- Rahaman, A., et al.
(author)
-
Coulomb breakup of neutron-rich Na-29,Na-30 isotopes near the island of inversion
- 2017
-
In: Journal of Physics G: Nuclear and Particle Physics. - : IOP Publishing. - 0954-3899 .- 1361-6471. ; 44:4, s. 045101-
-
Journal article (peer-reviewed)abstract
- First results are reported on the ground state configurations of the neutron-rich Na-29,Na-30 isotopes, obtained via Coulomb dissociation (CD) measurements. The invariant mass spectra of these nuclei have been obtained through measurement of the four-momenta of all decay products after Coulomb excitation of those nuclei on a Pb-208 target at energies of 400-430 MeV/nucleon using the FRS-ALADIN-LAND setup at GSI, Darmstadt. Integrated inclusive CD cross-sections (CD) of 89 (7) mb and 167 (13) mb for one neutron removal from Na-29 and Na-30, respectively, have been extracted up to an excitation energy of 10 MeV. The major part of one neutron removal, CD cross-sections of those nuclei populate the core, in its ground state. A comparison with the direct breakup model, suggests the predominant occupation of the valence neutron in the ground state of Na-29 (3/2(+)) and Na-30 (2(+)) is the d-orbital with a small contribution from the s-orbital, which are coupled with the ground state of the core. One of the major components of the ground state configurations of these nuclei are Na-28(gs)(1(+)) circle times v(s,d) and Na-29(gs)(3/2(+)) circle times v(s,d), respectively. The ground state spin and parity of these nuclei obtained from this experiment are in agreement with earlier reported values. The spectroscopic factors for the valence neutron occupying the s and d orbitals for these nuclei in the ground state have been extracted and reported for the first time. A comparison of the experimental findings with shell model calculation using the MCSM suggests a lower limit of around 4.3 MeV of the sd-pf shell gap in Na-30.
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46. |
- Rahaman, A., et al.
(author)
-
Study of ground state wave-function of the Neutron-rich 29,30Na isotopes through coulomb breakup
- 2014
-
In: EPJ Web of Conferences. - : EDP Sciences. - 2101-6275 .- 2100-014X. ; 66
-
Conference paper (peer-reviewed)abstract
- Coulomb breakup of unstable neutron rich nuclei 29,30Na around the 'island of inversion' has been studied at energy around 434 MeV/nucleon and 409 MeV/nucleon respectively. Four momentum vectors of fragments, decay neutron from excited projectile and γ-rays emitted from excited fragments after Coulomb breakup are measured in coincidence. For these nuclei, the low-lying dipole strength above one neutron threshold can be explained by direct breakup model. The analysis for Coulomb breakup of 29,30Na shows that large amount of the cross section yields the 28Na, 29Na core in ground state. The predominant ground-state configuration of 29,30Na is found to be 28Na(g.s) νs1/2 and 29Na(g.s) νs1/2,respectively. © Owned by the authors, published by EDP Sciences, 2014.
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47. |
- Revel, A., et al.
(author)
-
Strong Neutron Pairing in core+4n Nuclei
- 2018
-
In: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 120:15
-
Journal article (peer-reviewed)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.
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48. |
- Ribeiro, G., et al.
(author)
-
Structure of Be-13 studied in proton knockout from B-14
- 2018
-
In: Physical Review C. - 2469-9985 .- 2469-9993. ; 98:2
-
Journal article (peer-reviewed)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.
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49. |
- Röder, M., et al.
(author)
-
Coulomb dissociation of 20,21 N
- 2016
-
In: Physical Review C - Nuclear Physics. - 2469-9985 .- 2469-9993 .- 0556-2813. ; 93:6
-
Journal article (peer-reviewed)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
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50. |
- Syndikus, I., et al.
(author)
-
Probing the Z = 6 spin-orbit shell gap with (p,2p) quasi-free scattering reactions
- 2020
-
In: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 809
-
Journal article (peer-reviewed)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.
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