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Author  |
Gjestvang, D. et al; Algora, A. |
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Title |
Examination of how properties of a fissioning system impact isomeric yield ratios of the fragments |
Type |
Journal Article |
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Year |
2023 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
108 |
Issue |
6 |
Pages |
064602 - 12pp |
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Keywords |
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Abstract |
The population of isomeric states in the prompt decay of fission fragments-so-called isomeric yield ratios (IYRs)-is known to be sensitive to the angular momentum J that the fragment emerged with, and may therefore contain valuable information on the mechanism behind the fission process. In this work, we investigate how changes in the fissioning system impact the measured IYRs of fission fragments to learn more about what parameters affect angular momentum generation. To enable this, a new technique for measuring IYRs is first demonstrated. It is based on the time of arrival of discrete gamma rays, and has the advantage that it enables the study of the IYR as a function of properties of the partner nucleus. This technique is used to extract the IYR of 134Te, strongly populated in actinide fission, from the three different fissioning systems: 232Th(n, f), 238U(n, f), at two different neutron energies, as well as 252Cf(sf). The impacts of changing the fissioning system, the compound nuclear excitation energy, the minimum J of the binary partner, and the number of neutrons emitted on the IYR of 134Te are determined. The decay code TALYS is used in combination with the fission simulation code FREYA to calculate the primary fragment angular momentum from the IYR. We find that the IYR of 134Te has a slope of 0.004 +/- 0.002 with increase in compound nucleus (CN) mass. When investigating the impact on the IYR of increased CN excitation energy, we find no change with an energy increase similar to the difference between thermal and fast fission. By varying the mass of the partner fragment emerging with 134Te, it is revealed that the IYR of 134Te is independent of the total amount of prompt neutrons emitted from the fragment pair. This indicates that neutrons carry minimal angular momentum away from the fission fragments. Comparisons with the FREYA+TALYS simulations reveal that the average angular momentum in 134Te following 238U(n, f) is 6.0 h over bar . This is not consistent with the value deduced from recent CGMF calculations. Finally, the IYR sensitivity to the angular momentum of the primary fragment is discussed. These results are not only important to help understanding the underlying mechanism in nuclear fission, but can also be used to constrain and benchmark fission models, and are relevant to the gamma -ray heating problem of reactors. |
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Address |
[Gjestvang, D.; Siem, S.; Nemer, J.; Paulsen, W.; Popovitch, Y.] Univ Oslo, Dept Phys, N-0316 Oslo, Norway, Email: dorthea.gjestvang@fys.uio.no |
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Amer Physical Soc |
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English |
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2469-9985 |
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Notes |
WOS:001160674400006 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5947 |
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Author |
Girard-Alcindor, V. et al; Domingo-Pardo, C. |
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Title |
New narrow resonances observed in the unbound nucleus F-15 |
Type |
Journal Article |
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Year |
2022 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
105 |
Issue |
5 |
Pages |
L051301 - 7pp |
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Keywords |
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Abstract |
The structure of the unbound F-15 nucleus is investigated using the inverse kinematics resonant scattering of a radioactive O-14 beam impinging on a CH2 target. The analysis of H-1(O-14, p) O-14 and H-1(O-14, 2p) N-13 reactions allowed the confirmation of the previously observed narrow 1/2(-) resonance, near the two-proton decay threshold, and the identification of two new narrow 5/2(-) and 3/2(-) resonances. The newly observed levels decay by 1p emission to the ground of O-14, and by sequential 2p emission to the ground state of N-13 via the 1(-) resonance of O-14. Gamow shell model (GSM) analysis of the experimental data suggests that the wave functions of the 5/2(-) and 3/2(-) resonances may be collectivized by the continuum coupling to nearby 2p- and 1p-decay channels. The observed excitation function H-1(O-14, p) O-14 and resonance spectrum in F-15 are well reproduced in the unified framework of the GSM. |
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Address |
[Girard-Alcindor, V.; Santos, F. de Oliveira; Ploszajczak, M.; Lemasson, A.; Clement, E.; Ramos, D.; Rejmund, M.; Ackermann, D.; Bastin, B.; Caceres, L.; De France, G.; Giraud, S.; Goupil, J.; Grevy, S.; Kamalou, O.; Kamenyero, A.; Leblond, S.; Lefevre, A.; Li, H.; Morfouace, P.; Stodel, C.; Thomas, J. C.] Grand Accelerateur Natl Ions Lourds GANIL, CEA, DRF CNRS, IN2P3, Bvd Henri Becquerel, F-14076 Caen, France, Email: stefan@ipno.in2p3.fr |
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Amer Physical Soc |
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English |
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ISSN |
2469-9985 |
ISBN |
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Conference |
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Notes |
WOS:000811520800003 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5268 |
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Author |
Ghazi Moradi, F. et al; Huyuk, T. |
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Title |
Character of particle-hole excitations in Ru-94 deduced from gamma-ray angular correlation and linear polarization measurements |
Type |
Journal Article |
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Year |
2014 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
89 |
Issue |
1 |
Pages |
014301 - 9pp |
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Keywords |
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Abstract |
Linear polarization and angular correlations of gamma-rays depopulating excited states in the neutron-deficient nucleus Ru-94(44)50 have been measured, enabling firm spin-parity assignments for several excited states in this nucleus. The deduced multipolarities of strong transitions in the yrast structure were found to be mostly of stretched M1, E1, and E2 types and, in most cases, in agreement with previous tentative assignments. The deduced multipolarity of the 1869 keV and the connecting 257 and 1641 keV transitions indicates that the state at 6358 keV excitation energy has spin parity 12(1)(-) rather than 12(3)(+) as proposed in previous works. The presence of a 12(1)(-) state is interpreted within the framework of large-scale shell-model calculations as a pure proton-hole state dominated by the pi(p(1/2)(-1)circle times g(9/2)(-5)) and pi(p(3/2)(-1) g(9/2)(-5)) configurations. A new positive-parity state is observed at 6103 keV and is tentatively assigned as 12(2)(+). The 14(1)(-) state proposed earlier is reassigned as 13(4)(-) and is interpreted as being dominated by neutron particle-hole core excitations. The strengths of several E1 transitions have been measured and are found to provide a signature of core-excited configurations. |
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Address |
[Moradi, F. Ghazi; Qi, C.; Cederwall, B.; Atac, A.; Baeck, T.; Liotta, R.; Doncel, M.; Johnson, A.] Royal Inst Technol, KTH, Dept Phys, SE-10691 Stockholm, Sweden, Email: farnazg@kth.se |
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Amer Physical Soc |
Place of Publication |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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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 |
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Conference |
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Notes |
WOS:000332148300001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1724 |
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Author |
Gerst, R.B. et al; Algora, A. |
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Title |
Prompt and delayed gamma spectroscopy of neutron-rich Kr-94 and observation of a new isomer |
Type |
Journal Article |
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Year |
2020 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
102 |
Issue |
6 |
Pages |
064323 - 8pp |
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Keywords |
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Abstract |
Prompt and delayed gamma-ray spectroscopy of the neutron-rich Kr-94 was performed, as part of the fission campaign at the ALTO facility of the IPN Orsay, using the fast-neutron-induced fission reaction U-238(n, f) in combination with the nu-Ball array, a novel hybrid gamma spectrometer for energy and lifetime measurements. Several new yrast and nonyrast transitions were observed for the first time, extending the previously known level scheme. Additionally, we report on the observation of a new short-lived isomer at 3444 keV with a half-life of 32(3) ns. The analysis of the Nilsson orbitals obtained from Gogny cranked Hartree-Fock-Bogoliubov calculations suggests a (9(-)) spin and an oblate deformation for this isomer corresponding to a two-quasineutron state, indicating an isomeric structure very similar to that of the neighboring isotones Sr-96 and Se-92. |
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Address |
[Gerst, R-B; Blazhev, A.; Warr, N.; Haefner, G.] Univ Cologne, Inst Kemphys, D-50937 Cologne, Germany, Email: rgerst@ikp.uni-koeln.de |
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Publisher |
Amer Physical Soc |
Place of Publication |
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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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Conference |
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Notes |
WOS:000602816700004 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4662 |
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Author |
Garzon, E.J.; Xie, J.J.; Oset, E. |
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Title |
Case in favor of the N*(1700)(3/2(-)) |
Type |
Journal Article |
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Year |
2013 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
87 |
Issue |
5 |
Pages |
055204 - 12pp |
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Keywords |
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Abstract |
Using an interaction extracted from the local hidden-gauge Lagrangians, which brings together vector and pseudoscalar mesons, and the coupled channels rho N (s wave), pi N (d wave), pi Delta (s wave), and pi Delta (d wave), we look in the region ofv root s = 1400-1850 MeV and find two resonances dynamically generated by the interaction of these channels, which are naturally associated to N*(1520)(3/2(-)) and N*(1700)(3/2(-)). N*(1700)(3/2(-)) appears neatly as a pole in the complex plane. The free parameters of the theory are chosen to fit the pi N (d-wave) data. Both the real and imaginary parts of the pi N amplitude vanish in our approach in the vicinity of this resonance, which is similar to what happens in experimental determinations and which makes this signal very weak in this channel. This feature could explain why this resonance does not show up in some experimental analyses, but the situation is analogous to that of the f(0)(980) resonance, the second scalar meson after sigma[f(0)(500)] in the pi pi(d-wave) amplitude. The unitary coupled channel approach followed here, in connectionwith the experimental data, leads automatically to a pole in the 1700-MeV region and makes this second 3/2-resonance unavoidable. |
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Address |
Univ Valencia, CSIC, Inst Invest Paterna, Ctr Mixto,Dept Fis Teor, Valencia 46071, Spain |
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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:000319058200003 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1455 |
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| Permanent link to this record |
