| Records |
| Author |
Zheng, Y. et al; Gadea, A. |
| Title |
gamma-ray linear polarization measurements and (g(9/2))(-3) neutron alignment in Ru-91 |
Type |
Journal Article |
| Year |
2013 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
| Volume |
87 |
Issue |
4 |
Pages |
044328 - 10pp |
| Keywords |
|
| Abstract |
Linear polarization measurements have been performed for gamma rays in Ru-91 produced with the Ni-58(Ar-36,2p1n gamma)Ru-91 reaction at a beam energy of 111 MeV. The EXOGAM Ge clover array has been used to measure the gamma-gamma coincidences, gamma-ray linear polarization, and gamma-ray angular distributions. The polarization sensitivity of the EXOGAM clover detectors acting as Compton polarimeters has been determined in the energy range 0.3-1.3 MeV. Several transitions have been observed for the first time. Measurements of linear polarization and angular distribution have led to the firm assignments of spin differences and parity of high-spin states in Ru-91. More specifically, calculations using a semiempirical shell model were performed to understand the structures of the first and second (21/2(+)) and (17/2(+)) levels. The results are in good agreement with the experimental data, supporting the interpretation of the nonyrast (21/2(+)) and (17/2(+)) states in terms of the J(max) and J(max) – 2 members of the seniority-three nu(g(9/2))(-3) multiplet. |
| Address |
CNRS, IN2P3, CEA, GANIL,DSM, F-14076 Caen 5, France, Email: zhengyong@impcas.ac.cn |
| Corporate Author |
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Thesis |
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| Publisher |
Amer Physical Soc |
Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0556-2813 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:000317866200004 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
1409 |
| Permanent link to this record |
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| Author |
Cederwall, B. et al; Algora, A.; Gadea, A. |
| Title |
Evidence for a spin-aligned neutron-proton paired phase from the level structure of Pd-92 |
Type |
Journal Article |
| Year |
2011 |
Publication |
Nature |
Abbreviated Journal |
Nature |
| Volume |
469 |
Issue |
7328 |
Pages |
68-71 |
| Keywords |
|
| Abstract |
Shell structure and magic numbers in atomic nuclei were generally explained by pioneering work(1) that introduced a strong spin-orbit interaction to the nuclear shell model potential. However, knowledge of nuclear forces and the mechanisms governing the structure of nuclei, in particular far from stability, is still incomplete. In nuclei with equal neutron and proton numbers (N = Z), enhanced correlations arise between neutrons and protons (two distinct types of fermions) that occupy orbitals with the same quantum numbers. Such correlations have been predicted to favour an unusual type of nuclear superfluidity, termed isoscalar neutron-proton pairing(2-6), in addition to normal isovector pairing. Despite many experimental efforts, these predictions have not been confirmed. Here we report the experimental observation of excited states in the N = Z = 46 nucleus Pd-92. Gamma rays emitted following the Ni-58(Ar-36,2n)Pd-92 fusion-evaporation reaction were identified using a combination of state-of-the-art high-resolution c-ray, charged-particle and neutron detector systems. Our results reveal evidence for a spin-aligned, isoscalar neutron-proton coupling scheme, different from the previous prediction(2-6). We suggest that this coupling scheme replaces normal superfluidity (characterized by seniority coupling(7,8)) in the ground and low-lying excited states of the heaviest N = Z nuclei. Such strong, isoscalar neutron-proton correlations would have a considerable impact on the nuclear level structure and possibly influence the dynamics of rapid proton capture in stellar nucleosynthesis. |
| Address |
[Cederwall, B.; Moradi, F. Ghazi; Back, T.; Johnson, A.; Blomqvist, J.; Andgren, K.; Lagergren, K.; Liotta, R.; Qi, C.; Hadinia, B.; Khaplanov, A.; Persson, A.; Sandzelius, M.] Royal Inst Technol, Dept Phys, SE-10691 Stockholm, Sweden, Email: cederwall@nuclear.kth.se |
| Corporate Author |
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Thesis |
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| Publisher |
Nature Publishing Group |
Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0028-0836 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
ISI:000285921600032 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
588 |
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| Author |
AGATA Collaboration (Akkoyun, S. et al); Algora, A.; Barrientos, D.; Domingo-Pardo, C.; Egea, F.J.; Gadea, A.; Huyuk, T.; Kaci, M.; Mendez, V.; Rubio, B.; Salt, J.; Tain, J.L. |
| Title |
AGATA-Advanced GAmma Tracking Array |
Type |
Journal Article |
| Year |
2012 |
Publication |
Nuclear Instruments & Methods in Physics Research A |
Abbreviated Journal |
Nucl. Instrum. Methods Phys. Res. A |
| Volume |
668 |
Issue |
|
Pages |
26-58 |
| Keywords |
AGATA; gamma-Ray spectroscopy; gamma-Ray tracking; HPGe detectors; Digital signal processing; Pulse-shape and gamma-ray tracking algorithms; Semiconductor detector performance and simulations |
| Abstract |
The Advanced GAmma Tracking Array (AGATA) is a European project to develop and operate the next generation gamma-ray spectrometer. AGATA is based on the technique of gamma-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 gamma 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 gamma-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. |
| Address |
[Boston, A. J.; Boston, H. C.; Colosimo, S.; Cooper, R. J.; Cresswell, J. R.; Dimmock, M. R.; Filmer, F.; Grint, A. N.; Harkness, L. J.; Judson, D. S.; Mather, A. R.; Moon, S.; Nelson, L.; Nolan, P. J.; Norman, M.; Oxley, D. C.; Rigby, S.; Sampson, J.; Scraggs, D. P.; Seddon, D.; Slee, M.; Stanios, T.; Thornhill, J.; Unsworth, C.; Wells, D.] Univ Liverpool, Oliver Lodge Lab, Liverpool L69 7ZE, Merseyside, England, Email: a.j.boston@liverpool.ac.uk |
| Corporate Author |
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Thesis |
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| Publisher |
Elsevier Science Bv |
Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0168-9002 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:000300864200005 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
923 |
| Permanent link to this record |
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| Author |
Dijon, A. et al; Gadea, A.; Huyuk, T. |
| Title |
Discovery of a new isomeric state in Ni-68: Evidence for a highly deformed proton intruder state |
Type |
Journal Article |
| Year |
2012 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
| Volume |
85 |
Issue |
3 |
Pages |
031301 - 5pp |
| Keywords |
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| Abstract |
We report on the observation of a new isomeric state in Ni-68. We suggest that the newly observed state at 168(1) keV above the first 2(+) state is a pi(2p-2h) 0(+) state across the major Z = 28 shell gap. Comparison with theoretical calculations indicates a pure proton intruder configuration and the deduced low-lying structure of this key nucleus suggests a possible shape coexistence scenario involving a highly deformed state. |
| Address |
[Dijon, A.; Clement, E.; de France, G.; Dudouet, J.; Jacquot, B.; Lebhertz, D.; Schmitt, C.; Zheng, Y.] CEA DSM CNRS IN2P3, GANIL, F-14076 Caen, France |
| Corporate Author |
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Thesis |
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| Publisher |
Amer Physical Soc |
Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0556-2813 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:000301185200001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
931 |
| Permanent link to this record |
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| Author |
AGATA Collaboration (Crespi, F.C.L. et al); Gadea, A. |
| Title |
Response of AGATA segmented HPGe detectors to gamma rays up to 15.1 MeV |
Type |
Journal Article |
| Year |
2013 |
Publication |
Nuclear Instruments & Methods in Physics Research A |
Abbreviated Journal |
Nucl. Instrum. Methods Phys. Res. A |
| Volume |
705 |
Issue |
|
Pages |
47-54 |
| Keywords |
AGATA; Gamma-ray spectroscopy; Gamma-ray tracking; HPGe detectors; Pulse-shape and gamma-ray tracking algorithms; Semiconductor detector performance and simulations |
| Abstract |
The response of AGATA segmented HPGe detectors to gamma rays in the energy range 2-15 MeV was measured. The 15.1 MeV gamma rays were produced using the reaction d(B-11,n gamma)C-12 at E-beam=19.1 MeV, while gamma rays between 2 and 9 MeV were produced using an Am-Be-Fe radioactive source. The energy resolution and linearity were studied and the energy-to-pulse-height conversion resulted to be linear within 0.05%.Experimental interaction multiplicity distributions are discussed and compared with the results of Geant4 simulations. It is shown that the application of gamma-ray tracking allows a suppression of background radiation caused by n-capture in Ge nuclei. Finally the Doppler correction for the 15.1 MeV gamma line, performed using the position information extracted with Pulse-shape analysis is discussed. |
| Address |
[Crespi, F. C. L.; Avigo, R.; Camera, F.; Bottoni, S.; Bracco, A.; Ceruti, S.; Giaz, A.; Leoni, S.; Nicolini, R.; Pellegri, L.; Riboldi, S.; Vandone, V.] Univ Milan, Dipartimento Fis, I-20133 Milan, Italy, Email: fabio.crespi@mi.infn.it |
| Corporate Author |
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Thesis |
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| Publisher |
Elsevier Science Bv |
Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0168-9002 |
ISBN |
|
Medium |
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| Area |
|
Expedition |
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Conference |
|
| Notes |
WOS:000314826000009 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
1329 |
| Permanent link to this record |
