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n_TOF Collaboration (Amaducci, S. et al); Domingo-Pardo, C.; Tain, J.L. |
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Title |
Measurement of the U-235(n, f) cross section relative to the Li-6(n, t) and B-10(n,alpha) standards from thermal to 170 keV neutron energy range at n_TOF |
Type |
Journal Article |
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Year |
2019 |
Publication |
European Physical Journal A |
Abbreviated Journal |
Eur. Phys. J. A |
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Volume |
55 |
Issue |
7 |
Pages |
120 - 19pp |
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Abstract |
.The U-235(n, f ) cross section was measured at n_TOF relative to Li-6(n, t) and B-10(n,alpha) , with high resolution ( L=183.49(2) m) and in a wide energy range (25meV-170keV) with 1.5% systematic uncertainty, making use of a stack of six samples and six silicon detectors placed in the neutron beam. This allowed us to make a direct comparison of the yields of the U-235(n, f ) and of the two reference reactions under the same experimental conditions, and taking into account the forward/backward emission asymmetry. A hint of an anomaly in the 10-30keV neutron energy range had been previously observed in other experiments, indicating a cross section systematically lower by several percent relative to major evaluations. The present results indicate that the cross section in the 9-18keV neutron energy range is indeed overestimated by almost 5% in the recently released evaluated data files ENDF/B-VIII.0 and JEFF3.3, as a consequence of a 7% overestimate in a single GMA node in the IAEA reference file. Furthermore, these new high-resolution data confirm the existence of resonance-like structures in the keV neutron energy region. The results here reported may lead to a reduction of the uncertainty in the 1-100keV neutron energy region. Finally, from the present data, a value of 249.7 +/- 1.4( stat )+/- 0.94( syst ) b<bold>eV has been extracted for the cross section integral between </bold>7.8 and 11eV, confirming the value of 247.5 +/- 3 b<bold>eV recently established as a standard</bold>. |
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Address |
[Amaducci, S.; Cosentino, L.; Finocchiaro, P.; Musumarra, A.] INFN, Lab Nazl Sud, Catania, Italy, Email: finocchiaro@lns.infn.it |
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Publisher |
Springer |
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English |
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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 |
1434-6001 |
ISBN |
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Expedition |
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Conference |
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Notes |
WOS:000477050900001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4083 |
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Permanent link to this record |
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Author |
Yeung, T.T. et al; Morales, A.I.; Tain, J.L.; Alcala, G.; Algora, A.; Agramunt, J.; Orrigo, S.E.A.; Rodriguez-Garcia, D.; Tarifeño-Saldivia, A.; Victoria, J.A. |
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Title |
First Exploration of Monopole-Driven Shell Evolution above the N=126 Shell Closure: New Millisecond Isomers in Tl-213 and Tl-215 |
Type |
Journal Article |
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Year |
2024 |
Publication |
Physical Review Letters |
Abbreviated Journal |
Phys. Rev. Lett. |
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Volume |
133 |
Issue |
7 |
Pages |
072501 - 7pp |
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Keywords |
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Abstract |
Isomer spectroscopy of heavy neutron-rich nuclei beyond the N = 126 closed shell has been performed for the first time at the Radioactive Isotope Beam Factory of the RIKEN Nishina Center. New millisecond isomers have been identified at low excitation energies, 985.3(19) keV in Tl-213 and 874(5) keV in Tl-215. The measured half-lives of 1.34(5) ms in Tl-213 and 3.0(3) ms in Tl-215 suggest spins and parities 11/2(-) with the single proton-hole configuration pi h(11/2) as leading component. They are populated via E1 transitions by the decay of higher-lying isomeric states with proposed spin and parity 17/2(+), interpreted as arising from a single pi s(1/2) proton hole coupled to the 8(+) seniority isomer in the PbA + 1 cores. The lowering of the 11/2(-) states is ascribed to an increase of the pi h(11/2) proton effective single-particle energy as the second nu g(9/2) orbital is filled by neutrons, owing to a significant reduction of the proton-neutron monopole interaction between the pi h(11/2) and nu g(9/2) orbitals. The new ms isomers provide the first experimental observation of shell evolution in the almost unexplored N > 126 nuclear region below doubly magic Pb-208. |
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Address |
[Yeung, T. T.; Niikura, M.; Kokubun, K.; Mizuno, R.; Sakurai, H.] Univ Tokyo, Dept Phys, 7-3-1 Hongo, Tokyo 1130033, Japan, Email: Ana.Morales@ific.uv.es; |
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Publisher |
Amer Physical Soc |
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English |
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ISSN |
0031-9007 |
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Expedition |
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Conference |
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Notes |
WOS:001308049400010 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
6256 |
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Permanent link to this record |
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Author |
Rubio, B.; Gelletly, W.; Algora, A.; Nacher, E.; Tain, J.L. |
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Title |
Beta decay studies with total absorption spectroscopy and the Lucrecia spectrometer at ISOLDE |
Type |
Journal Article |
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Year |
2017 |
Publication |
Journal of Physics G |
Abbreviated Journal |
J. Phys. G |
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Volume |
44 |
Issue |
8 |
Pages |
084004 - 25pp |
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Keywords |
beta decay; strength functions; total absorption gamma spectroscopy; nuclear shapes |
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Abstract |
Here we present the experimental activities carried out at ISOLDE with the total absorption spectrometer Lucrecia, a large 4 pi scintillator detector designed to absorb a full gamma cascade following beta decay. This spectrometer is designed to measure beta-feeding to excited states without the systematic error called Pandemonium. The set up allows the measurement of decays of very short half life. Experimental results from several campaigns, that focus on the determination of the shapes of beta-decaying nuclei by measuring their beta decay strength distributions as a function of excitation energy in the daughter nucleus, are presented. |
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Address |
[Rubio, B.; Gelletly, W.; Algora, A.; Tain, J. L.] Univ Valencia, CSIC, IFIC, E-46980 Paterna, Spain, Email: berta.rubio@ific.uv.es |
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Publisher |
Iop Publishing Ltd |
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English |
Summary Language |
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Abbreviated Series Title |
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Edition |
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ISSN |
0954-3899 |
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Conference |
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Notes |
WOS:000404730700001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3192 |
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Permanent link to this record |
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Author |
n_TOF Collaboration (Mastromarco, M. et al); Domingo-Pardo, C.; Tain, J.L. |
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Title |
High accuracy, high resolution U-235(n,f) cross section from n_TOF (CERN) from 18 meV to 10 keV |
Type |
Journal Article |
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Year |
2022 |
Publication |
European Physical Journal A |
Abbreviated Journal |
Eur. Phys. J. A |
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Volume |
58 |
Issue |
8 |
Pages |
147 - 13pp |
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Keywords |
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Abstract |
The U-235(n,f) cross section was measured in a wide energy range (18 meV-170 keV) at the nTOF facility at CERN, relative to Li-6(n,t) and B-10(n,alpha) standard reactions, with high resolution and accuracy, with a setup based on a stack of six samples and six silicon detectors placed in the neutron beam. In this paper we report on the results in the region between 18 meV and 10 keV neutron energy. A resonance analysis has been performed up to 200 eV, with the code SAMMY. The resulting fission kernels are compared with the ones extracted on the basis of the resonance parameters of the most recent major evaluated data libraries. A comparison of the nTOF data with the evaluated cross sections is also performed from thermal to 10 keV neutron energy for the energy-averaged cross section in energy groups of suitably chosen width. A good agreement, within 0.5%, is found on average between the new results and the latest evaluated data files ENDF/B-VIII.0 and JEFF-3.3, as well as with respect to the broad group average fission cross section established in the framework of the standard working group of IAEA (the so-called reference file). However, some discrepancies, of up to 4%, are still present in some specific energy regions. The new dataset here presented, characterized by a unique combination of high resolution and accuracy, low background and wide energy range, can help to improve the evaluations from the Resolved Resonance Region up to 10 keV, also reducing the uncertainties that affect this region. |
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Address |
[Mastromarco, M.; Colonna, N.; Diacono, D.] Ist Nazl Fis Nucl, Sez Bari, Bari, Italy, Email: amaducci@lns.infn.it |
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Thesis |
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Publisher |
Springer |
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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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 |
1434-6001 |
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:000840312100002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5328 |
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Permanent link to this record |
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Author |
Orrigo, S.E.A.; Tain, J.L.; Mont-Geli, N.; Tarifeño-Saldivia, A.; Fraile, L.M.; Grieger, M.; Agramunt, J.; Algora, A.; Bemmerer, D.; Calvino, F.; Cortes, G.; De Blas, A.; Dillmann, I.; Dominguez Bugarin, A.; Garcia, R.; Nacher, E.; Tolosa-Delgado, A. |
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Title |
Long-term evolution of the neutron rate at the Canfranc Underground Laboratory |
Type |
Journal Article |
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Year |
2022 |
Publication |
European Physical Journal C |
Abbreviated Journal |
Eur. Phys. J. C |
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Volume |
82 |
Issue |
9 |
Pages |
814 - 11pp |
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Keywords |
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Abstract |
We report results on the long-term variation of the neutron counting rate at the Canfranc Underground Laboratory, of importance for several low-background experiments installed there, including rare-event searches. The measurement campaign was performed employing the High Efficiency Neutron Spectrometry Array (HENSA) mounted in Hall A and lasted 412 live days. The present study is the first long-term measurement of the neutron rate with sensitivity over a wide range of neutron energies (from thermal up to 0.1 GeV and beyond) performed in any underground laboratory so far. Data on the environmental variables inside the experimental hall (radon concentration, air temperature, air pressure and humidity) were also acquired during all the measurement campaign. We have investigated for the first time the evolution of the neutron rate for different energies of the neutrons and its correlation with the ambient variables. |
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Address |
[Orrigo, S. E. A.; Tain, J. L.; Agramunt, J.; Algora, A.; Nacher, E.; Tolosa-Delgado, A.] Univ Valencia, Inst Fis Corpuscular, CSIC, Valencia 46071, Spain, Email: Sonja.Orrigo@ific.uv.es |
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Corporate Author |
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Thesis |
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Publisher |
Springer |
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 |
1434-6044 |
ISBN |
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Expedition |
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Conference |
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Notes |
WOS:000853333800003 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5358 |
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Permanent link to this record |