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Author  |
n_TOF Collaboration (Barbagallo, M. et al); Domingo-Pardo, C.; Tain, J.L.; Tarifeño-Saldivia, A. |
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Title |
Be-7(n,alpha)He-4 Reaction and the Cosmological Lithium Problem: Measurement of the Cross Section in a Wide Energy Range at n_TOF at CERN |
Type |
Journal Article |
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Year |
2016 |
Publication |
Physical Review Letters |
Abbreviated Journal |
Phys. Rev. Lett. |
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Volume |
117 |
Issue |
15 |
Pages |
152701 - 7pp |
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Keywords |
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Abstract |
The energy-dependent cross section of the (7)Bed(n,alpha)He-4 reaction, of interest for the so-called cosmological lithium problem in big bang nucleosynthesis, has been measured for the first time from 10 meV to 10 keV neutron energy. The challenges posed by the short half-life of Be-7 and by the low reaction cross section have been overcome at nTOF thanks to an unprecedented combination of the extremely high luminosity and good resolution of the neutron beam in the new experimental area (EAR2) of the nTOF facility at CERN, the availability of a sufficient amount of chemically pure Be-7, and a specifically designed experimental setup. Coincidences between the two alpha particles have been recorded in two Si-Be-7-Si arrays placed directly in the neutron beam. The present results are consistent, at thermal neutron energy, with the only previous measurement performed in the 1960s at a nuclear reactor. The energy dependence reported here clearly indicates the inadequacy of the cross section estimates currently used in BBN calculations. Although new measurements at higher neutron energy may still be needed, the n_TOF results hint at a minor role of this reaction in BBN, leaving the long-standing cosmological lithium problem unsolved. |
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Address |
[Barbagallo, M.; Colonna, N.; Damone, L.; Mastromarco, M.; Mazzone, A.; Tagliente, G.; Variale, V.] Ist Nazl Fis Nucl, Sez Bari, Bari, Italy, Email: nicola.colonna@ba.infn.it |
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Publisher |
Amer Physical Soc |
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English |
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Edition |
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ISSN |
0031-9007 |
ISBN |
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Expedition |
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Conference |
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Notes |
WOS:000384479300003 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2822 |
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Author |
n_TOF Collaboration (Belloni, F. et al); Domingo-Pardo, C.; Tain, J.L. |
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Title |
Measurement of the neutron-induced fission cross-section of Am-241 at the time-of-flight facility n_TOF |
Type |
Journal Article |
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Year |
2013 |
Publication |
European Physical Journal A |
Abbreviated Journal |
Eur. Phys. J. A |
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Volume |
49 |
Issue |
1 |
Pages |
2 - 6pp |
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Keywords |
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Abstract |
The neutron-induced fission cross-section of Am-241 has been measured relative to the standard fission cross-section of U-235 between 0.5 and 20 MeV. The experiment was performed at the CERN nTOF facility. Fission fragments were detected by a fast ionization chamber by discriminating against the alpha-particles from the high radioactivity of the samples. The high instantaneous neutron flux and the low background of the nTOF facility enabled us to obtain uncertainties of approximate to 5%. With the present results it was possible to resolve discrepancies between previous data sets and to confirm current evaluations, thus providing important information for design studies of future reactors with improved fuel burn-up. |
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Corporate Author |
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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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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:000315048100002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1399 |
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Author |
n_TOF Collaboration (Belloni, F. et al); Domingo-Pardo, C.; Tain, J.L. |
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Title |
Neutron-induced fission cross section measurement of U-233, Am-241 and Am-243 in the energy range 0.5 MeV <= E-n <= 20 MeV at n_TOF at CERN |
Type |
Journal Article |
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Year |
2012 |
Publication |
Physica Scripta |
Abbreviated Journal |
Phys. Scr. |
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Volume |
T150 |
Issue |
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Pages |
014005 - 4pp |
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Keywords |
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Abstract |
Neutron-induced fission cross section measurements of U-233, Am-243 and Am-241 relative to U-235 have been carried out at the neutron time-of-flight facility n_TOF at CERN. A fast ionization chamber has been employed. All samples were located in the same detector; therefore the studied elements and the reference U-235 target are subject to the same neutron beam. |
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Address |
[Belloni, F.; Milazzo, P. M.; Abbondanno, U.; Fujii, K.; Moreau, C.] Ist Nazl Fis Nucl, Trieste, Italy, Email: francesca.belloni@cea.fr |
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Thesis |
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Publisher |
Iop Publishing Ltd |
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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 |
0031-8949 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000309605500006 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1184 |
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Author |
n_TOF Collaboration (Belloni, F. et al); Domingo-Pardo, C.; Tain, J.L. |
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Title |
Neutron-induced fission cross-section of U-233 in the energy range 0.5 < E-n < 20 MeV |
Type |
Journal Article |
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Year |
2011 |
Publication |
European Physical Journal A |
Abbreviated Journal |
Eur. Phys. J. A |
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Volume |
47 |
Issue |
1 |
Pages |
2 - 7pp |
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Keywords |
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Abstract |
The neutron-induced fission cross-section of U-233 has been measured at the CERN nTOF facility relative to the standard fission cross-section of U-235 between 0.5 and 20MeV. The experiment was performed with a fast ionization chamber for the detection of the fission fragments and to discriminate against alpha-particles from the natural radioactivity of the samples. The high instantaneous flux and the low background of the nTOF facility result in data with uncertainties of approximate to 3%, which were found in good agreement with previous experiments. The high quality of the present results allows to improve the evaluation of the U-233(n, f) cross-section and, consequently, the design of energy systems based on the Th/U cycle. |
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Address |
[Belloni, F.; Milazzo, P. M.; Abbondanno, U.; Fujii, K.; Moreau, C.] Ist Nazl Fis Nucl INFN, Trieste, Italy, Email: paolo.milazzo@ts.infn.it |
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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 |
1434-6001 |
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 |
ISI:000288550800006 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
539 |
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| Permanent link to this record |
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Author |
n_TOF Collaboration (Belloni, F. et al); Domingo-Pardo, C.; Tain, J.L. |
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Title |
Measurement of the neutron-induced fission cross-section of Am-243 relative to U-235 from 0.5 to 20 MeV |
Type |
Journal Article |
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Year |
2011 |
Publication |
European Physical Journal A |
Abbreviated Journal |
Eur. Phys. J. A |
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Volume |
47 |
Issue |
12 |
Pages |
160 - 8pp |
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Keywords |
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Abstract |
The ratio of the neutron-induced fission cross-sections of Am-243 and U-235 was measured in the energy range from 0.5 to 20 MeV with uncertainties of approximate to 4%. The experiment was performed at the CERN n_TOF facility using a fast ionization chamber. With the good counting statistics that could be achieved thanks to the high instantaneous flux and the low backgrounds, the present results are useful for resolving discrepancies in previous data sets and are important for future reactors with improved fuel burn-up. |
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Address |
[Belloni, F.; Calviani, M.; Mastinu, P.; Milazzo, P. M.; Abbondanno, U.; Fujii, K.; Gramegna, F.; Moreau, C.] Ist Nazl Fis Nucl INFN, Lab Nazl Legnaro, Trieste, Italy, Email: paolo.milazzo@ts.infn.it |
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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 |
1434-6001 |
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:000300285100005 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
904 |
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| Permanent link to this record |
