| Records |
| Author |
Dudouet, J. et al; Gadea, A.; Perez-Vidal, R.M. |
| Title |
Excitations of the magic N=50 neutron-core revealed in Ga-81 |
Type |
Journal Article |
| Year |
2019 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
| Volume |
100 |
Issue |
1 |
Pages |
011301 - 6pp |
| Keywords |
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Abstract  |
The high-spin states of the neutron-rich Ga-81, with three valence protons outside a Ni-78 core, were measured. The measurement involved prompt gamma-ray spectroscopy of fission fragments isotopically identified using the combination of the variable mode spectrometer (VAMOS++) and the advanced gamma tracking array (AGATA). The new gamma-ray transitions, observed in coincidence with Ga-81 ions, and the corresponding level scheme do not confirm the high-spin levels reported earlier. The newly observed high-spin states in Ga-81 are interpreted using the results of state-of-the-art large-scale shell model (LSSM) calculations. The lower excitation energy levels are understood as resulting from the recoupling of three valence protons to the closed doubly magic core, while the highest excitation energy levels correspond to excitations of the magic N = 50 neutron core. These results support the doubly magic character of Ni-78 and the persistence of the N = 50 shell closure but also highlight the presence of strong proton-neutron correlations associated with the promotion of neutrons across the magic N = 50 shell gap, only few nucleons away from Ni-78. |
| Address |
[Dudouet, J.; Maquart, G.; Stezowski, O.; Ducoin, C.; Guinet, D.; Redon, N.] Univ Lyon 1, CNRS IN2P3, IPN Lyon, F-69622 Villeurbanne, France, Email: jeremie.dudouet@csnsm.in2p3.fr |
| 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 |
2469-9985 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
|
| Notes |
WOS:000475500200001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
4095 |
| Permanent link to this record |
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| Author |
AGATA Collaboration (Vogt, A. et al); Gadea, A. |
| Title |
Isomers and high-spin structures in the N=81 isotones Xe-135 and Ba-137 |
Type |
Journal Article |
| Year |
2017 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
| Volume |
95 |
Issue |
2 |
Pages |
024316 - 17pp |
| Keywords |
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| Abstract |
The high-spin structures and isomers of the N = 81 isotones Xe-135 and Ba-137 are investigated after multinucleon-transfer (MNT) and fusion-evaporation reactions. Both nuclei are populated (i) in Xe-136+ U-238 and (ii) Xe-136+ Pb-208 MNT reactions employing the high-resolution Advanced Gamma Tracking Array (AGATA) coupled to the magnetic spectrometer PRISMA, (iii) in the Xe-136+ Pt-198 MNT reaction employing the gamma-ray array GAMMASPHERE in combination with the gas-detector array CHICO, and (iv) via a B-11+ Te-130 fusion-evaporation reaction with the HORUS gamma-ray array at the University of Cologne. The high-spin level schemes of Xe-135 and Ba-137 are considerably extended to higher energies. The 2058-keV (19/2(-)) state in Xe-135 is identified as an isomer, closing a gap in the systematics along the N = 81 isotones. Its half-life is measured to be 9.0(9) ns, corresponding to a reduced transition probability of B(E2,19/2(-) -> 15/2(-)) = 0.52(6) W.u. The experimentally deduced reduced transition probabilities of the isomeric states are compared to shell-model predictions. Latest shell-model calculations reproduce the experimental findings generally well and provide guidance to the interpretation of the new levels. |
| Address |
[Vogt, A.; Birkenbach, B.; Reiter, P.; Blazhev, A.; Arnswald, K.; Eberth, J.; Fu, B.; Geibel, K.; Hess, H.; Hirsch, R.; Jolie, J.; Kaya, L.; Lewandowski, L.; Liang, X.; Mueller-Gatermann, C.; Queiser, M.; Radeck, F.; Rosiak, D.; Saed-Samii, N.; Schneiders, D.; Seidlitz, M.; Siebeck, B.; Steinbach, T.; Wiens, A.; Zell, K. O.] Univ Cologne, Inst Kernphys, D-50937 Cologne, Germany, Email: andreas.vogt@ikp.uni-koeln.de |
| 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 |
2469-9985 |
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:000393944100004 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
2967 |
| Permanent link to this record |
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| Author |
AGATA Collaboration (Kaya, L. et al); Gadea, A. |
| Title |
Identification of high-spin proton configurations in Ba-136 and Ba-137 |
Type |
Journal Article |
| Year |
2019 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
| Volume |
99 |
Issue |
1 |
Pages |
014301 - 19pp |
| Keywords |
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| Abstract |
The high-spin structures of Ba-136 and Ba-137 are investigated after multinucleon-transfer (MNT) and fusion-evaporation reactions. Ba-136 is populated in a Xe-136 + U-238 MNT reaction employing the high-resolution Advanced GAmma Tracking Array (AGATA) coupled to the magnetic spectrometer PRISMA at the Laboratori Nazionali di Legnaro, Italy, and in two Be-9 + Te-130 fusion-evaporation reactions using the High-efficiency Observatory for gamma-Ray Unique Spectroscopy (HORUS) at the FN tandem accelerator of the University of Cologne, Germany. Furthermore, both isotopes are populated in an elusive reaction channel in the B-11 + Te-130 fusion-evaporation reaction utilizing the HORUS gamma-ray array. The level scheme above the J(pi) = 10(+) isomer in Ba-136 is revised and extended up to an excitation energy of approximately 5.5 MeV. From the results of angular-correlation measurements, the E-x = 3707- and E-x = 4920-keV states are identified as the bandheads of positive- and negative-parity cascades. While the high-spin regimes of both Te-132 and Xe-134 are characterized by high-energy 12(+) -> 10(+) transitions, the Ba-136 E2 ground-state band is interrupted by negative-parity states only a few hundred keV above the J(pi) = 10(+) isomer. Furthermore, spins are established for several hitherto unassigned high-spin states in Ba-137. The new results close a gap along the high-spin structure of N < 82 Ba isotopes. Experimental results are compared to large-scale shell-model calculations employing the GCN50:82, Realistic SM, PQM130, and SN100PN interactions. The calculations suggest that the bandheads of the positive-parity bands in both isotopes are predominantly of proton character. |
| Address |
[Kaya, L.; Vogt, A.; Reiter, P.; Mueller-Gatermann, C.; Blazhev, A.; Arnswald, K.; Birkenbach, B.; Droste, M.; Eberth, J.; Fransen, C.; Hess, H.; Hetzenegger, R.; Hirsch, R.; Jolie, J.; Lewandowski, L.; Rosiak, D.; Saed-Samii, N.; Seidlitz, M.; Weinert, M.; Wolf, K.; Zell, K. O.] Univ Cologne, Inst Kernphys, D-50937 Cologne, Germany, Email: levent.kaya@ikp.uni-koeln.de |
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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 |
2469-9985 |
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:000454768000002 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
3859 |
| Permanent link to this record |
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| Author |
AGATA Collaboration (Soderstrom, P.A. et al); Gadea, A. |
| Title |
Interaction position resolution simulations and in-beam measurements of the AGATA HPGe detectors |
Type |
Journal Article |
| Year |
2011 |
Publication |
Nuclear Instruments & Methods in Physics Research A |
Abbreviated Journal |
Nucl. Instrum. Methods Phys. Res. A |
| Volume |
638 |
Issue |
1 |
Pages |
96-109 |
| Keywords |
gamma-ray tracking; AGATA; Monte Carlo simulations; HPGe detectors; Fusion-evaporation reactions |
| Abstract |
The interaction position resolution of the segmented HPGe detectors of an AGATA triple cluster detector has been studied through Monte Carlo simulations and in an in-beam experiment. A new method based on measuring the energy resolution of Doppler-corrected gamma-ray spectra at two different target to detector distances is described. This gives the two-dimensional position resolution in the plane perpendicular to the direction of the emitted gamma-ray. The gamma-ray tracking was used to determine the full energy of the gamma-rays and the first interaction point, which is needed for the Doppler correction. Five different heavy-ion induced fusion-evaporation reactions and a reference reaction were selected for the simulations. The results of the simulations show that the method works very well and gives a systematic deviation of <1 mm in the FVVHM of the interaction position resolution for the gamma-ray energy range from 60 keV to 5 MeV. The method was tested with real data from an in-beam measurement using a (30)5i beam at 64 MeV on a thin C-12 target. Pulse-shape analysis of the digitized detector waveforms and gamma-ray tracking was performed to determine the position of the first interaction point, which was used for the Doppler corrections. Results of the dependency of the interaction position resolution on the gamma-ray energy and on the energy, axial location and type of the first interaction point, are presented. The FVVHM of the interaction position resolution varies roughly linearly as a function of gamma-ray energy from 8.5 mm at 250 key to 4 mm at 1.5 MeV, and has an approximately constant value of about 4 mm in the gamma-ray energy range from 1.5 to 4 MeV. |
| Address |
[Soderstrom, P. -A.; Nyberg, J.; Al-Adili, A.; Atac, A.; Veyssiere, C.] Uppsala Univ, Dept Phys & Astron, SE-75121 Uppsala, Sweden, Email: P-A.Soderstrom@physics.uu.se |
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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 |
ISI:000290082600015 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
619 |
| Permanent link to this record |
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| Author |
Luo, X.L. et al; Agramunt, J.; Egea, F.J.; Gadea, A.; Huyuk, T. |
| Title |
Pulse pile-up identification and reconstruction for liquid scintillator based neutron detectors |
Type |
Journal Article |
| Year |
2018 |
Publication |
Nuclear Instruments & Methods in Physics Research A |
Abbreviated Journal |
Nucl. Instrum. Methods Phys. Res. A |
| Volume |
897 |
Issue |
|
Pages |
59-65 |
| Keywords |
Pile-up; Digital; First-order derivative; Neutron-gamma discrimination; Liquid scintillator |
| Abstract |
The issue of pulse pile-up is frequently encountered in nuclear experiments involving high counting rates, which will distort the pulse shapes and the energy spectra. A digital method of off-line processing of pile-up pulses is presented. The pile-up pulses were firstly identified by detecting the downward-going zero-crossings in the first-order derivative of the original signal, and then the constituent pulses were reconstructed based on comparing the pile-up pulse with four models that are generated by combining pairs of neutron and.. standard pulses together with a controllable time interval. The accuracy of this method in resolving the pile-up events was investigated as a function of the time interval between two pulses constituting a pile-up event. The obtained results show that the method is capable of disentangling two pulses with a time interval among them down to 20 ns, as well as classifying them as neutrons or gamma rays. Furthermore, the error of reconstructing pile-up pulses could be kept below 6% when successive peaks were separated by more than 50 ns. By applying the method in a high counting rate of pile-up events measurement of the NEutron Detector Array (NEDA), it was empirically found that this method can reconstruct the pile-up pulses and perform neutron-gamma discrimination quite accurately. It can also significantly correct the distorted pulse height spectrum due to pile-up events. |
| Address |
[Luo, X. L.] Acad Mil Med Sci, Natl Innovat Inst Def Technol, Beijing 100010, Peoples R China, Email: delongtmac@163.com |
| 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:000433206800010 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
3591 |
| Permanent link to this record |
