| 1. |
- Bergmann, U. C., et al.
(författare)
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Analysis of decay data from neutron-rich nuclei
- 2001
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Ingår i: European Physical Journal A. - 1434-601X .- 1434-6001. ; 11:3, s. 279-284
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Tidskriftsartikel (refereegranskat)abstract
- The beta -decays of the neutron-rich nuclei Be-12 and Ne-29 have been studied. The statistical correlations between the almost identical half-lives of Be-12 and its daughter B-12 are analysed for a large sample of Be-12 decay data. Stringent mutual bounds are obtained on the parameter set, leading to a precise determination of the Be-12 half-life of 21.50 +/- 0.04 ms. From a simultaneous detection of beta -particles and neutrons from the decay of Ne-29 the neutron emission probability, P-n, is determined to 17 +/- 5%. No indication of two-neutron emission is seen from this nucleus. An upper limit of 2.2% (90% confidence level) is established for P-2n.
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| 2. |
- 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
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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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| 3. |
- IDS Collaboration, HASH(0x3dac240), et al.
(författare)
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Beta-delayed proton emission from 20Mg
- 2016
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Ingår i: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-601X .- 1434-6001. ; 52:10, s. 304-
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Tidskriftsartikel (refereegranskat)abstract
- Beta-delayed proton emission from 20 Mg has been measured at ISOLDE, CERN, with the ISOLDE Decay Station (IDS) setup including both charged-particle and gamma-ray detection capabilities. A total of 27 delayed proton branches were measured including seven so far unobserved. An updated decay scheme, including three new resonances above the proton separation energy in 20 Na and more precise resonance energies, is presented. Beta-decay feeding to two resonances above the Isobaric Analogue State (IAS) in 20 Na is observed. This may allow studies of the 4032.9(2.4)keV resonance in 19 Ne through the beta decay of 20 Mg, which is important for the astrophysically relevant reaction 15O(?,?)19Ne. Beta-delayed protons were used to obtain a more precise value for the half-life of 20 Mg, 91.4(1.0)ms.
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| 4. |
- Jensen, E. A.M., et al.
(författare)
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Detailed study of the decay of 21Mg
- 2024
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Ingår i: European Physical Journal A. - 1434-601X .- 1434-6001. ; 60:7
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Tidskriftsartikel (refereegranskat)abstract
- Beta-delayed proton and gamma emission in the decay of 21Mg has been measured at ISOLDE, CERN with the ISOLDE Decay Station (IDS) set-up. The existing decay scheme is updated, in particular what concerns proton transitions to excited states in 20Ne. Signatures of interference in several parts of the spectrum are used to settle spin and parity assignments to highly excited states in 21Na. The previously reported βpα branch is confirmed. A half-life of 120.5(4) ms is extracted for 21Mg. The revised decay scheme is employed to test mirror symmetry in the decay and to extract the beta strength distribution of 21Mg that is compared with theory.
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| 5. |
- Lund, M. V., et al.
(författare)
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Beta-delayed proton emission from 21Mg
- 2015
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Ingår i: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-601X .- 1434-6001. ; 51:9, s. Art. no. 113-
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Tidskriftsartikel (refereegranskat)abstract
- Beta-delayed proton emission from 21Mg has been measured at ISOLDE, CERN, with a detection setup consisting of two charged-particle telescopes surrounding the decay point. Altogether 27 βp branches were measured with center-of-mass energies between 0.4–7.2 MeV. Seven new βp branches were observed. Beta-delayed protons were used to determine the half-life of 21Mg as 118.6 ± 0.5 ms. From a line shape fit of the βp branches we extract the widths, spins, and parities of the resonances of 21Na. An improved interpretation of the decay scheme in accordance with the results obtained in reaction studies is presented.
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| 6. |
- Mach, H., et al.
(författare)
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New structure information on Mg-30, Mg-31 and Mg-32
- 2005
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Ingår i: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-601X .- 1434-6001. ; 25, s. 105-109
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Konferensbidrag (refereegranskat)abstract
- The fast timing beta gamma gamma(t) method was applied to investigate the level lifetimes in Mg-30,Mg-31,Mg-32. Levels in Mg have been populated in beta and beta-delayed neutron emission of Na, at the ISOLDE facility. From the gamma gamma coincidences a number of new states have been identified and new level schemes were constructed for 30 31,32 Mg. The following preliminary half lives have been determined: T-1/2 = 3.9(4) ns for the 1789 keV state in Mg-30, T-1/2 = 133(8) ps and 10.5(8) us for the 221 keV and 461 keV states in Mg-31, respectively, and T1/2 = 16(4) ps for the 885 keV level in 32Mg. The 1789 keV level was established as a candidate for the intruder 0(+) configuration in Mg-30 with a possible strong E0 branch to the ground state.
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| 7. |
- Mach, H., et al.
(författare)
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On the enhanced E1 transitions in the K=3/2 parity doublet band in Ra-223
- 2016
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Ingår i: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-6001 .- 1434-601X. ; 52:6
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Tidskriftsartikel (refereegranskat)abstract
- We have applied the fast timing beta gamma gamma(t) technique to remeasure lifetimes of selected states in Ra-223 populated in the beta(-) decay of Fr-223. T-1/2 = 587(12) ps and 210(13) ps have been obtained for the 3/2(-) and 5/2(-) states at 50.1 and 79.7 keV, that are more accurate than the previous values of 630(70) ps and 166(55) ps, respectively. Our vertical bar D0 vertical bar value of 0.155(10) e.fm obtained for the K = 3/2 configuration together with the available values of vertical bar D0 vertical bar for the K = 1/2 and K = 5/2 parity doublet bands establish the configuration dependence of vertical bar D0 vertical bar at low spins in this nucleus. Results of theoretical calculations performed for Ra-223, using the quasiparticle-phonon model (QPM) with inclusion of the Coriolis coupling, reasonably well reproduce octupole correlations in this nucleus.
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| 8. |
- Marganiec, J., et al.
(författare)
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Studies of continuum states in (16) Ne using three-body correlation techniques
- 2015
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Ingår i: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-601X .- 1434-6001. ; 51:1, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- Two-proton decay of the unbound nucleus Ne-16 , produced in one-neutron knockout from a 500 MeV/u Ne-17 beam, has been studied at GSI. The ground state, at a resonance energy 1.388(15) MeV, ( MeV) above the O-14 +p+p threshold, and two narrow resonances at MeV and 7.57(6) MeV have been investigated. A comparison of the energy difference between the first excited 2(+) state and the 0(+) ground state in Ne-16 with its mirror nucleus C-16 reveals a small Thomas-Ehrman shift (TES) of keV. A trend of the TES for the T = 2 quintet is obtained by completing the known data with a prediction for F-16 obtained from an IMME analysis. The decay mechanisms of the observed three resonances were revealed from an analysis of the energy and angular correlations of the O-14 +p+p decay products. The ground state decay can be considered as a genuine three-body (democratic) mode and the excited states decay sequentially via states in the intermediate nucleus F-15 , the 3.22 MeV state predominantly via the F-15 ground-state resonance, while the 7.57 MeV state decays via the 5/2(+) resonance in F-15 at 2.8 MeV above the O-14 +p+p threshold. Further, from an analysis of angular correlations, the spin-parity of the 7.57 MeV state has been determined as and assigned as the third 2(+) state in Ne-16 based on a comparison with C-16.
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| 9. |
- Riisager, K., et al.
(författare)
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Search for beta-delayed proton emission from 11 Be
- 2020
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Ingår i: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-601X .- 1434-6001. ; 56:3
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Tidskriftsartikel (refereegranskat)abstract
- We report on an attempt to reproduce the observation of β--delayed proton emission from 11Be through detection of the final state nucleus 10Be with accelerator mass spectrometry. Twelve samples were collected at the ISOLDE facility at CERN at different separator settings, allowing tests of different sources of contamination to be carried out. The observed amounts of 10Be per collected 11Be rule out several contamination sources, but do not agree internally. Formation of BeH molecular ions in the ion source may explain our data, in which case an upper limit of the βp branching ratio of 2.2 × 10 - 6 can be derived.
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| 10. |
- Sambi, S., et al.
(författare)
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12C+p resonant elastic scattering in the Maya active target
- 2015
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Ingår i: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-601X .- 1434-6001. ; 51:2, s. 1-7
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Tidskriftsartikel (refereegranskat)abstract
- In a proof-of-principle measurement, the Maya active target detector was employed for a C-12(p, p) resonant elastic scattering experiment in inverse kinematics. The excitation energy region from 0 to 3MeV above the proton breakup threshold in N-13 was investigated in a single measurement. By using the capability of the detector to localize the reaction vertex and record the tracks of the recoiling protons, data covering a large solid angle could be utilized, at the same time keeping an energy resolution comparable with that of direct-kinematics measurements. The excitation spectrum in N-13 was fitted using the R-matrix formalism. The level parameters extracted are in good agreement with previous studies. The active target proved its potential for the study of resonant elastic scattering in inverse kinematics with radioactive beams, when detection efficiency is of primary importance.
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