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Author ![sorted by Author field, ascending order (up)](img/sort_asc.gif) |
n_TOF Collaboration (Barbagallo, M. et al); Domingo-Pardo, C.; Giubrone, G.; Tain, J.L. |
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Title |
High-accuracy determination of the neutron flux at 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 |
12 |
Pages |
156 - 11pp |
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Abstract |
The neutron flux of the nTOF facility at CERN was measured, after installation of the new spallation target, with four different systems based on three neutron-converting reactions, which represent accepted cross sections standards in different energy regions. A careful comparison and combination of the different measurements allowed us to reach an unprecedented accuracy on the energy dependence of the neutron flux in the very wide range (thermal to 1 GeV) that characterizes the nTOF neutron beam. This is a pre-requisite for the high accuracy of cross section measurements at n_TOF. An unexpected anomaly in the neutron-induced fission cross section of U-235 is observed in the energy region between 10 and 30keV, hinting at a possible overestimation of this important cross section, well above currently assigned uncertainties. |
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Address |
[Barbagallo, M.; Colonna, N.; Mastromarco, M.; Meaze, M.; Tagliente, G.; Variale, V.] Ist Nazl Fis Nucl, Sez Bari, I-70125 Bari, Italy, Email: massimo.barbagallo@ba.infn.it |
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Springer |
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English |
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ISSN |
1434-6001 |
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Conference |
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Notes |
WOS:000328351000001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1663 |
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Author ![sorted by Author field, ascending order (up)](img/sort_asc.gif) |
n_TOF Collaboration (Barbagallo, M. et al); Domingo-Pardo, C.; Tain, J.L. |
![goto web page (via DOI) doi](img/doi.gif)
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Title |
Experimental setup and procedure for the measurement of the Be-7(n,p)Li-7 reaction at n_TOF |
Type |
Journal Article |
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Year |
2018 |
Publication |
Nuclear Instruments & Methods in Physics Research A |
Abbreviated Journal |
Nucl. Instrum. Methods Phys. Res. A |
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Volume |
887 |
Issue |
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Pages |
27-33 |
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Keywords |
Cosmological Lithium problem; Big bang nucleosynthesis; Be-7(n,p)Li-7 reaction; n_TOF spallation neutron source |
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Abstract |
Following the completion of the second neutron beam line and the related experimental area (EAR2) at the n_TOF spallation neutron source at CERN, several experiments were planned and performed. The high instantaneous neutron flux available in EAR2 allows to investigate neutron induced reactions with charged particles in the exit channel even employing targets made out of small amounts of short-lived radioactive isotopes. After the successful measurement of the Be-7(n,alpha)alpha cross section, the Be-7(n,p)Li-7 reaction was studied in order to provide still missing cross section data of relevance for Big Bang Nucleosynthesis (BBN), in an attempt to find a solution to the cosmological Lithium abundance problem. This paper describes the experimental setup employed in such a measurement and its characterization. |
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Address |
[Barbagallo, M.; Mastromarco, M.; Damone, L. A.; Mazzone, A.; Colonna, N.; Tagliente, G.; Variale, V.] Ist Nazl Fis Nucl, Sez Bari, Bari, Italy, Email: finocchiaro@lns.infn.ir |
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Publisher |
Elsevier Science Bv |
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English |
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ISSN |
0168-9002 |
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Notes |
WOS:000427814400005 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3528 |
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Author ![sorted by Author field, ascending order (up)](img/sort_asc.gif) |
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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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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Thesis |
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Publisher |
Amer Physical Soc |
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English |
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ISSN |
0031-9007 |
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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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Permanent link to this record |
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Author ![sorted by Author field, ascending order (up)](img/sort_asc.gif) |
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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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 |
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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 ![sorted by Author field, ascending order (up)](img/sort_asc.gif) |
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 |