| 51. |
- Cederkäll, Joakim, et al.
(författare)
-
REX-ISOLDE - experiences from the first year of operation
- 2004
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Ingår i: Nuclear Physics A. - : Elsevier BV. - 0375-9474. ; 746, s. 17-17
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Konferensbidrag (refereegranskat)abstract
- The Radioactive beam EXperiment (REX) at CERN-ISOLDE has been commissioned and the first experiments successfully completed during 2002 and 2003. The concept used for post-acceleration has proven to be flexible and the experimental program has therefore been extended during the past year. This paper relays some experiences drawn from using the machine in the current program and also conveys some plans for the future.
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| 52. |
- Cederkäll, Joakim, et al.
(författare)
-
Sub-Barrier Coulomb Excitation of ^110Sn and Its Implications for the ^100Sn Shell Closure
- 2007
-
Ingår i: Physical Review Letters. - 1079-7114. ; 98:17, s. 172501-
-
Tidskriftsartikel (refereegranskat)abstract
- The first excited 2+ state of the unstable isotope 110Sn has been studied in safe Coulomb excitation at 2.82 MeV/u using the MINIBALL array at the REX-ISOLDE post accelerator at CERN. This is the first measurement of the reduced transition probability of this state using this method for a neutron deficient Sn isotope. The strength of the approach lies in the excellent peak-to-background ratio that is achieved. The extracted reduced transition probability, B(E2:0+-->2+)=0.220±0.022e2b2, strengthens the observation of the evolution of the B(E2) values of neutron deficient Sn isotopes that was observed recently in intermediate-energy Coulomb excitation of 108Sn. It implies that the trend of these reduced transition probabilities in the even-even Sn isotopes is not symmetric with respect to the midshell mass number A=116 as 100Sn is approached.
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| 53. |
- Chakraborty, S., et al.
(författare)
-
Ground-state configuration of neutron-rich Al-35 via Coulomb breakup
- 2017
-
Ingår i: Physical Review C. - 2469-9985 .- 2469-9993. ; 96:3, s. 1965-
-
Tidskriftsartikel (refereegranskat)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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| 54. |
- Chulkov, L. V., et al.
(författare)
-
Is there a low-lying 1(-) state in He-10?
- 2013
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Ingår i: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 720:4-5, s. 344-346
-
Tidskriftsartikel (refereegranskat)abstract
- In a recent paper by S.I. Sidorchuk et al., Phys. Rev. Lett. 108 (2012) 202502, angular correlations in the decay of He-10 were interpreted as a coherent superposition of a 0(+), 1(-) and 2(+) states. It was concluded that it is the 1- state that dominates in the energy region 4.5-6 MeV. It is here demonstrated here that the experimental data might be understood without assuming the presence of a low-lying 1(-) state.
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| 55. |
- Chulkov, L. V., et al.
(författare)
-
Large spin alignment of the unbound He-5 fragment after fragmentation of 240 MeV/nucleon He-6
- 1997
-
Ingår i: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 79:2, s. 201-204
-
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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| 56. |
- Chulkov, L. V., et al.
(författare)
-
Three-body correlations in electromagnetic dissociation of Borromean nuclei: The He-6 case
- 2005
-
Ingår i: Nuclear Physics A. - : Elsevier BV. - 0375-9474. ; 759:1-2, s. 23-42
-
Tidskriftsartikel (refereegranskat)abstract
- Dissociation of He-6 on a lead target has been studied at 240 MeV/u. The four-momenta of the two neutrons in coincidence with alpha-particles have been measured and used to reconstruct the three-body energy and angular correlations in the final state. For the first time, three-body correlations were included in the analysis of the He-6 dissociation data, and compared with calculations assuming a dipole mode for the electromagnetic dissociation. In addition, the experimental data have been analyzed using a series expansion of the final transition amplitude into hyperspherical functions, showing the importance of both nn and alpha n final-state interactions. It is shown that the dissociation process is governed by a transition of one neutron from the p-shell in the 6He ground state to the s-shell in the continuum further indicating that the role of the transition through an intermediate He-5(3/2(-)) state is more important than expected. (c) 2005 Elsevier B.V. All rights reserved.
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| 57. |
- Cortina-Gil, D., et al.
(författare)
-
CALIFA, a Dedicated Calorimeter for the R3B/FAIR
- 2014
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Ingår i: Nuclear Data Sheets. - : Elsevier BV. - 1095-9904 .- 0090-3752. ; 120, s. 99-101
-
Tidskriftsartikel (refereegranskat)abstract
- The R3B experiment (Reactions with Relativistic Radioactive Beams) at FAIR (Facility for Antiproton and Ion Research) is a versatile setup dedicated to the study of reactions induced by high-energy radioactive beams. It will provide kinematically complete measurements with high efficiency, acceptance and resolution, making possible a broad physics program with rare-isotopes. CALIFA (CALorimeter for In-Flight detection of gamma-rays and high energy charged pArticles), is a complex detector based on scintillation crystals, that will surround the target of the R3B experiment. CALIFA will act as a total absorption gamma-calorimeter and spectrometer, as well as identifier of charged particles from target residues. This versatility is its most challenging requirement, demanding a huge dynamic range, to cover from low energy gamma-rays up to 300 MeV protons. This fact, along with the high-energy of the beams determine the conceptual design of the detector, presented in this paper, together with the technical solutions proposed for its construction.
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| 58. |
- Cortina-Gil, D., et al.
(författare)
-
One-neutron knockout of n-rich Ne isotopes at relativistic energies
- 2010
-
Ingår i: Nuclear Physics A. - : Elsevier BV. - 0375-9474. ; 834:1-4, s. 485C-487C
-
Konferensbidrag (refereegranskat)abstract
- Longitudinal fragment-momentum distributions resulting front one-neutron knockout of 40 different neutron-rich exotic species (Z ranging from 6-13) have been recently measured at high-energy (700 A MeV) using the FRS at GSI. This paper concentrates on results obtained for the Ne isotopic chain where five isotopes (Ne-24-Ne-28) have been Studied. The comparison of those experimental results with simple model calculations shows the evolution of the nuclear structure across neutron numbers N=14,16 in this transitional region in the neighbourhood of the island of inversion.
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| 59. |
- Cronqvist, M., et al.
(författare)
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Experimental-Determination of Cross-Talk between Neutron Detectors
- 1992
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Ingår i: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. - 0168-9002. ; 317:1-2, s. 273-280
-
Tidskriftsartikel (refereegranskat)abstract
- Neutron cross-talk measurements have been performed with 14.1 MeV neutrons for organic scintillator detectors with n-gamma discrimination capability. The probability for cross-talk between two 156 mm thick neutron detectors with a hexagonal cross section (effective diameter 167 mm) placed 0.33 m apart was found to be (2.5+/-1.1) 10(-4). A similar measurement between two 100 mm thick, cylindrically shaped detectors with 50 mm diameter and at 75 mm distance from each other yielded a cross-talk probability of (2.5+/-0.4) 10(-3). The measured cross-talk probabilities are in agreement with values from a Monte Carlo calculation.
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| 60. |
- Cubero, M., et al.
(författare)
-
Do Halo Nuclei Follow Rutherford Elastic Scattering at Energies Below the Barrier? The Case of 11Li
- 2012
-
Ingår i: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 109:26
-
Tidskriftsartikel (refereegranskat)abstract
- The first measurement of the elastic scattering of the halo nucleus 11Li and its core 9Li on 208Pb at energies near the Coulomb barrier is presented. The 11Li+208Pb elastic scattering shows a strong reduction with respect to the Rutherford cross section, even at energies well below the barrier and down to very small scattering angles. This drastic change of the elastic differential cross section observed in 11Li+208Pb is the consequence of the halo structure of 11Li, as it is not observed in the elastic scattering of its core 9Li at the same energies. Four-body continuum-discretized coupled-channels calculations, based on a three-body model of the 11Li projectile, are found to explain the measured angular distributions and confirm that the observed reduction is mainly due to the strong Coulomb coupling to the dipole states in the low-lying continuum of 11Li. These calculations suggest the presence of a low-lying dipole resonance in 11Li close to the breakup threshold.
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