| 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. |
- 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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| 3. |
- Kirsebom, O. S., et al.
(författare)
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First Accurate Normalization of the β -delayed α Decay of N 16 and Implications for the C 12 (α,γ) O 16 Astrophysical Reaction Rate
- 2018
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Ingår i: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 121:14
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Tidskriftsartikel (refereegranskat)abstract
- Published by the American Physical Society. The C12(α,γ)O16 reaction plays a central role in astrophysics, but its cross section at energies relevant for astrophysical applications is only poorly constrained by laboratory data. The reduced α width, γ11, of the bound 1- level in O16 is particularly important to determine the cross section. The magnitude of γ11 is determined via sub-Coulomb α-transfer reactions or the β-delayed α decay of N16, but the latter approach is presently hampered by the lack of sufficiently precise data on the β-decay branching ratios. Here we report improved branching ratios for the bound 1- level [bβ,11=(5.02±0.10)×10-2] and for β-delayed α emission [bβα=(1.59±0.06)×10-5]. Our value for bβα is 33% larger than previously held, leading to a substantial increase in γ11. Our revised value for γ11 is in good agreement with the value obtained in α-transfer studies and the weighted average of the two gives a robust and precise determination of γ11, which provides significantly improved constraints on the C12(α,γ) cross section in the energy range relevant to hydrostatic He burning.
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| 4. |
- Das, P., et al.
(författare)
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Study of exotic decay of Cs isotope close to the proton drip line
- 2020
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Ingår i: 27th International Nuclear Physics Conference (INPC2019) 29 July - 2 August 2019, Glasgow, UK. - : IOP Publishing. - 1742-6588. ; 1643
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Konferensbidrag (refereegranskat)abstract
- The neutron-deficient 115Cs was produced at ISOLDE, CERN by spallation reaction using 1.4 GeV proton on LaC2 target. The exotic decay modes were studied by using a charged particle array (DSSD and pad detectors) and a γ-detector array (four Clovers) at the ISOLDE decay station (IDS). In this report, results on observed β-delayed particle emission from 115Cs, a nucleus close to proton drip line, is presented. By measuring the time distribution in the delayed proton spectrum, the half-life of the ground state of 115Cs was extracted. The obtained half-life is in agreement with previous reported value. For the first time, the p-unbound states of 115Xe, obtained by measuring beta-delayed protons from 115Cs is reported.
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| 5. |
- Stryjczyk, M., et al.
(författare)
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Decay studies of the long-lived states in Tl 186
- 2020
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Ingår i: Physical Review C. - 2469-9985. ; 102:2
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Tidskriftsartikel (refereegranskat)abstract
- Decay spectroscopy of the long-lived states in Tl186 has been performed at the ISOLDE Decay Station at ISOLDE, CERN. The α decay from the low-spin (2-) state in Tl186 was observed for the first time and a half-life of 3.4-0.4+0.5 s was determined. Based on the α-decay energy, the relative positions of the long-lived states were fixed, with the (2-) state as the ground state, the 7(+) state at 77(56) keV, and the 10(-) state at 451(56) keV. The level scheme of the internal decay of the Tl186(10(-)) state [T1/2=3.40(9) s], which was known to decay solely through emission of 374-keV γ-ray transition, was extended and a lower limit for the β-decay branching bβ>5.9(3)% was determined. The extracted retardation factors for the γ decay of the 10(-) state were compared to the available data in neighboring odd-odd thallium isotopes indicating the importance of the πd3/2 shell in the isomeric decay and significant structure differences between Tl184 and Tl186.
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| 6. |
- Das, P., et al.
(författare)
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Exotic decay of 115Cs
- 2023
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Ingår i: Physical Review C. - 2469-9985. ; 108:6
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Tidskriftsartikel (refereegranskat)abstract
- The detailed study of the β+/EC decay of the very neutron-deficient and alpha-unbound nucleus 115Cs is presented. The measurement was performed at the ISOLDE, CERN where delayed charged particles and γ rays were detected. The observed delayed γ rays are in agreement with the previously reported characteristics γ rays of 115Xe. Based on the experimental observations, the tentative ground-state spin of 115Cs is suggested to be 7/2+ or 9/2+. Furthermore, the measured decay branching ratio of delayed protons exceeds the previously reported value. Additionally, new delayed α-branching ratio and several reconstructed proton and α-unbound excited states of 115Xe are being reported for the first time. The properties of proton-unbound states at excitation energies from 3.9–7.9 MeV have been obtained by fitting the delayed proton spectrum via the Bayesian method. The measured lifetimes of these proton-unbound states are in the order of zeptoseconds.
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| 7. |
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| 8. |
- Tack, LJW, et al.
(författare)
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Management of Gonads in Adults with Androgen Insensitivity: An International Survey
- 2018
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Ingår i: Hormone research in paediatrics. - : S. Karger AG. - 1663-2826 .- 1663-2818. ; 90:4, s. 236-246
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Tidskriftsartikel (refereegranskat)abstract
- <b><i>Background:</i></b> Complete and partial androgen insensitivity syndrome (CAIS, PAIS) are associated with an increased risk of gonadal germ cell cancer (GGCC). Recent guidelines recommend gonadectomy in women with CAIS in late adolescence. Nevertheless, many adult women prefer to retain their gonads. <b><i>Aims:</i></b> This study aims to explore attitudes towards gonadectomy in AIS in centres around the world, estimate the proportion of adults with retained gonads and/or who developed GGCC, and explore reasons for declining gonadectomy. <b><i>Methods:</i></b> A survey was performed among health care professionals who use the International DSD Registry (I-DSD). <b><i>Results:</i></b> Data were provided from 22 centres in 16 countries on 166 women (CAIS) and 26 men (PAIS). In CAIS, gonadectomy was recommended in early adulthood in 67% of centres; 19/166 (11.4%) women refused gonadectomy. Among 142 women who had gonadectomy, evidence of germ cell neoplasm in situ (GCNIS), the precursor of GGCC, was reported in 2 (1.4%) out of 8 from whom pathology results were formally provided. Nine out of 26 men with PAIS (34.6%) had retained gonads; 11% of centres recommended routine gonadectomy in PAIS. <b><i>Conclusion:</i></b> Although development of GGCC seems rare, gonadectomy after puberty is broadly recommended in CAIS; in PAIS this is more variable. Overall, our data reflect the need for evidence-based guidelines regarding prophylactic gonadectomy in AIS.
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| 9. |
- du Rietz, Rickard, et al.
(författare)
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Effective Charges in the fp Shell
- 2004
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Ingår i: Physical Review Letters. - 1079-7114. ; 93:22
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Tidskriftsartikel (refereegranskat)abstract
- Following the heavy-ion fusion-evaporation reaction S-32+Mg-24 at 95 MeV beam energy the lifetimes of analogue states in the T-z=+/-1/2 A=51 mirror nuclei Fe-51 and Mn-51 have been measured using the Cologne plunger device coupled to the GASP gamma-ray spectrometer. The deduced B(E2;27/2(-)-->23/2(-)) values afford a unique opportunity to probe isoscalar and isovector polarization charges and to derive effective proton and neutron charges, epsilon(p) and epsilon(n), in the fp shell. A comparison between the experimental results and several different large-scale shell-model calculations yields epsilon(p)similar to1.15e and epsilon(n)similar to0.80e.
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| 10. |
- du Rietz, Rickard, et al.
(författare)
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Investigation of High-spin States in 53Fe
- 2005
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 72:1
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Tidskriftsartikel (refereegranskat)abstract
- The fusion-evaporation reactions Si-28(S-32,1 alpha 2p1n)Fe-53 at 125 MeV and Mg-24(S-32,2p1n)Fe-53 at a 95-MeV beam energy were used to investigate excited states in Fe-53. The combination of the Gammasphere Ge detector array and ancillary devices led to the construction of an extensive level scheme comprising some 90 transitions connecting 40 states. The lifetime of the yrast 25/2(-) state and upper limits for the lifetimes of a number of additional states were determined using the Cologne plunger device coupled to the GASP gamma-ray spectrometer. The experimental results are compared to large-scale shell-model calculations using different sets of two-body matrix elements. In particular, predictions on electromagnetic decay properties such as lifetimes, branching ratios, and mixing ratios are studied in detail.
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| 11. |
- Gadea, A., et al.
(författare)
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Observation of Ni-54 : Cross-conjugate symmetry in f(7/2) mirror energy differences
- 2006
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 97:15, s. 152501-
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Tidskriftsartikel (refereegranskat)abstract
- Gamma decays from excited states up to J(pi)=6(+) in the N=Z-2 nucleus Ni-54 have been identified for the first time. Level energies are compared with those of the isobars Co-54 and Fe-54 and of the cross-conjugate nuclei of mass A=42. The good but puzzling f(7/2) cross-conjugate symmetry in mirror and triplet energy differences is analyzed. Shell model calculations reproduce the new data but the necessary nuclear charge-dependent phenomenology is not fully explained by modern nucleon-nucleon potentials.
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