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n_TOF Collaboration (Karadimos, D. et al); Domingo-Pardo, C.; Tain, J.L. |
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Title |
Neutron-induced fission cross section of U-234 measured at the CERN n_TOF facility |
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 |
4 |
Pages |
044606 - 11pp |
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Abstract |
The neutron-induced fission cross section of U-234 has been measured at the CERN nTOF facility relative to the standard fission cross section of U-235 from 20 keV to 1.4 MeV and of U-238 from 1.4 to 200 MeV. A fast ionization chamber (FIC) was used as a fission fragment detector with a detection efficiency of no less than 97%. The high instantaneous flux and the low background characterizing the nTOF facility resulted in wide-energy-range data (0.02 to 200 MeV), with high energy resolution, high statistics, and systematic uncertainties bellow 3%. Previous investigations around the energy of the fission threshold revealed structures attributed to beta-vibrational levels, which have been confirmed by the present measurements. Theoretical calculations have been performed, employing the TALYS code with model parameters tuned to fairly reproduce the experimental data. |
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Address |
[Karadimos, D.; Vlastou, R.; Diakaki, M.; Papadopoulos, C.; Tsinganis, A.] Natl Tech Univ Athens, GR-10682 Athens, Greece, Email: dkaradim@gmail.com |
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Publisher |
Amer Physical Soc |
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Language |
English |
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Series Volume |
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ISSN |
0556-2813 |
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Conference |
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Notes |
WOS:000341496900002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1924 |
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Permanent link to this record |
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Author |
n_TOF Collaboration (Mendoza, E. et al); Domingo-Pardo, C.; Tain, J.L. |
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Title |
Measurement and analysis of the Am-243 neutron capture cross section at the n_TOF facility at CERN |
Type |
Journal Article |
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Year |
2014 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
90 |
Issue |
3 |
Pages |
034608 - 16pp |
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Keywords |
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Abstract |
Background: The design of new nuclear reactors and transmutation devices requires to reduce the present neutron cross section uncertainties of minor actinides. Purpose: Improvement of the Am-243(n, gamma) cross section uncertainty. Method: The Am-243(n, gamma) cross section has been measured at the n_TOF facility at CERN with a BaF2 total absorption calorimeter, in the energy range between 0.7 eV and 2.5 keV. Results: The Am-243(n, gamma) cross section has been successfully measured in the mentioned energy range. The resolved resonance region has been extended from 250 eV up to 400 eV. In the unresolved resonance region our results are compatible with one of the two incompatible capture data sets available below 2.5 keV. The data available in EXFOR and in the literature have been used to perform a simple analysis above 2.5 keV. Conclusions: The results of this measurement contribute to reduce the Am-243(n, gamma) cross section uncertainty and suggest that this cross section is underestimated up to 25% in the neutron energy range between 50 eV and a few keV in the present evaluated data libraries. |
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Address |
[Mendoza, E.; Cano-Ott, D.; Guerrero, C.; Alvarez-Velarde, F.; Balibrea, J.; Gonzalez-Romero, E.; Martinez, T.; Villamarin, D.; Vicente, M. C.] CIEMAT, E-28040 Madrid, Spain |
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Publisher |
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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ISSN |
0556-2813 |
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Conference |
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Notes |
WOS:000341912100005 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1935 |
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Author |
Molina, F. et al; Rubio, B.; Agramunt, J.; Algora, A.; Domingo-Pardo, C.; Gadea, A.; Tain, J.L. |
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Title |
T-z =-1 -> 0 beta decays of Ni-54, Fe-50, Cr-46, and Ti-42 and comparison with mirror (He-3,t) measurements |
Type |
Journal Article |
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Year |
2015 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
91 |
Issue |
1 |
Pages |
014301 - 19pp |
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Abstract |
We have studied the beta decay of the T-z = -1, f(7/2) shell nuclei Ni-54, Fe-50, Cr-46, and Ti-42 produced in fragmentation reactions. The proton separation energies in the daughter T-z = 0 nuclei are relatively large (approximate to 4-5 MeV) so studies of the. rays are essential. The experiments were performed at GSI as part of the Stopped-beam campaign with the RISING setup consisting of 15 Euroball Cluster Ge detectors. From the newly obtained high precision beta-decay half-lives, excitation energies, and beta branching ratios, we were able to extract Fermi and Gamow-Teller transition strengths in these beta decays. With these improved results it was possible to compare in detail the Gamow-Teller (GT) transition strengths observed in beta decay including a sensitivity limit with the strengths of the T-z = +1 to T-z = 0 transitions derived from high resolution (He-3,t) reactions on the mirror target nuclei at RCNP, Osaka. The accumulated B(GT) strength obtained from both experiments looks very similar although the charge exchange reaction provides information on a broader energy range. Using the “merged analysis” one can obtain a full picture of the B(GT) over the full Q(beta) range. Looking at the individual transitions some differences are observed, especially for the weak transitions. Their possible origins are discussed. |
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Address |
[Molina, F.; Rubio, B.; Agramunt, J.; Algora, A.; Domingo-Pardo, C.; Gadea, A.] Univ Valencia, CSIC, Inst Fis Corpuscular, E-46071 Valencia, Spain, Email: berta.rubio@ific.uv.es |
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Corporate Author |
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Publisher |
Amer Physical Soc |
Place of Publication |
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Language |
English |
Summary Language |
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Abbreviated Series Title |
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Series Volume |
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ISSN |
0556-2813 |
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Conference |
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Notes |
WOS:000347924300002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2087 |
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Permanent link to this record |
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Author |
n_TOF Collaboration (Paradela, C. et al); Domingo-Pardo, C.; Giubrone, G.; Tain, J.L. |
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Title |
High-accuracy determination of the U-238/U-235 fission cross section ratio up to approximate to 1 GeV at n_TOF at CERN |
Type |
Journal Article |
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Year |
2015 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
91 |
Issue |
2 |
Pages |
024602 - 11pp |
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Keywords |
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Abstract |
The U-238 to U-235 fission cross section ratio has been determined at nTOF up to approximate to 1 GeV, with two different detection systems, in different geometrical configurations. A total of four datasets has been collected and compared. They are all consistent to each other within the relative systematic uncertainty of 3-4%. The data collected at nTOF have been suitably combined to yield a unique fission cross section ratio as a function of neutron energy. The result confirms current evaluations up to 200 MeV. Good agreement is also observed with theoretical calculations based on the INCL++ /Gemini++ combination up to the highest measured energy. The n_TOF results may help solve a long-standing discrepancy between the two most important experimental datasets available so far above 20 MeV, while extending the neutron energy range for the first time up to approximate to 1 GeV. |
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Address |
[Paradela, C.; Tarrio, D.; Leal-Cidoncha, E.; Duran, I.; Alvarez, H.] Univ Santiago de Compostela, Santiago De Compostela, Spain, Email: nicola.colonna@ba.infn.it |
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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:000350174000004 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2139 |
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Permanent link to this record |
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Author |
Tain, J.L. et al; Valencia, E.; Algora, A.; Agramunt, J.; Rubio, B.; Estevez, E.; Jordan, M.D. |
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Title |
Enhanced gamma-Ray Emission from Neutron Unbound States Populated in beta Decay |
Type |
Journal Article |
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Year |
2015 |
Publication |
Physical Review Letters |
Abbreviated Journal |
Phys. Rev. Lett. |
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Volume |
115 |
Issue |
6 |
Pages |
062502 - 5pp |
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Keywords |
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Abstract |
Total absorption spectroscopy is used to investigate the beta-decay intensity to states above the neutron separation energy followed by gamma-ray emission in Br-87,Br-88 and Rb-94. Accurate results are obtained thanks to a careful control of systematic errors. An unexpectedly large. intensity is observed in all three cases extending well beyond the excitation energy region where neutron penetration is hindered by low neutron energy. The gamma branching as a function of excitation energy is compared to Hauser-Feshbach model calculations. For Br-87 and Br-88 the gamma branching reaches 57% and 20%, respectively, and could be explained as a nuclear structure effect. Some of the states populated in the daughter can only decay through the emission of a large orbital angular momentum neutron with a strongly reduced barrier penetrability. In the case of neutron-rich Rb-94 the observed 4.5% branching is much larger than the calculations performed with standard nuclear statistical model parameters, even after proper correction for fluctuation effects on individual transition widths. The difference can be reconciled by introducing an enhancement of 1 order of magnitude in the photon strength to neutron strength ratio. An increase in the photon strength function of such magnitude for very neutron-rich nuclei, if it proves to be correct, leads to a similar increase in the (n, gamma) cross section that would have an impact on r process abundance calculations. |
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Address |
[Tain, J. L.; Valencia, E.; Algora, A.; Agramunt, J.; Rubio, B.; Estevez, E.; Jordan, M. D.] Univ Valencia, CSIC, Inst Fis Corpuscular, E-46071 Valencia, Spain, Email: tain@ific.uv.es |
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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 |
0031-9007 |
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:000359059100002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2319 |
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Permanent link to this record |