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Author n_TOF Collaboration (Cosentino, L. et al); Domingo-Pardo, C.; Tain, J.L.; Tarifeño-Saldivia, A.
Title Experimental setup and procedure for the measurement of the Be-7(n,alpha)alpha reaction at n_TOF Type Journal Article
Year (down) 2016 Publication Nuclear Instruments & Methods in Physics Research A Abbreviated Journal Nucl. Instrum. Methods Phys. Res. A
Volume 830 Issue Pages 197-205
Keywords Cosmological lithium problem; Big bang nucleosynthesis; Be-7(n,alpha)alpha reaction; n_TOF spallation neutron source
Abstract The newly built second experimental area EAR2 of then n_ToF spallation neutron source at CERN allows to perform (n, charged particles) experiments on short-lived highly radioactive targets. This paper describes a detection apparatus and the experimental procedure for the determination of the cross-section of the Be-7(n,alpha)alpha reaction, which represents one of the focal points toward the solution of the cosmological Lithium abundance problem, and whose only measurement, at thermal energy, dates back to 1963. The apparently unsurmountable experimental difficulties stemming from the huge Be-7 gamma-activity, along with the lack of a suitable neutron beam facility, had so far prevented further measurements. The detection system is subject to considerable radiation damage, but is capable of disentangling the rare reaction signals from the very high background. This newly developed setup could likely be useful also to study other challenging reactions requiring the detectors to be installed directly in the neutron beam.
Address [Cosentino, L.; Musumarra, A.; Pappalardo, A.; Piscopo, M.; Finocchiaro, P.; Cardella, R.; Heyse, J.; Jenkins, D. G.; Kaeppeler, F.; Katabuchi, T.; Kokkoris, M.; Lederer, C.; Lonsdale, S.; Massimi, C.; Mastinu, P.; Matteucci, F.; Mazzone, A.; Milazzo, P. M.; Nolte, R.; Patronis, N.; Pavlik, A.; Rauscher, T.; Schillebeeckx, P.; Stamatopoulos, A.; Tsinganis, A.; Vannini, G.; Vlastou, R.; Wallner, A.; Woods, P. J.] INFN Lab Nazl Sud, Catania, Italy, Email: FINOCCHIARO@LNS.INFN.IT
Corporate Author Thesis
Publisher Elsevier Science Bv Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0168-9002 ISBN Medium
Area Expedition Conference
Notes WOS:000381530300027 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 2792
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Author n_TOF Collaboration (Barbagallo, M. et al); Domingo-Pardo, C.; Tain, J.L.; Tarifeño-Saldivia, A.
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
Year (down) 2016 Publication Physical Review Letters Abbreviated Journal Phys. Rev. Lett.
Volume 117 Issue 15 Pages 152701 - 7pp
Keywords
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.
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
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0031-9007 ISBN Medium
Area Expedition Conference
Notes WOS:000384479300003 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 2822
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Author n_TOF Collaboration (Gunsing, F. et al); Domingo-Pardo, C.; Tain, J.L.; Tarifeño-Saldivia, A.
Title Nuclear data activities at the n_TOF facility at CERN Type Journal Article
Year (down) 2016 Publication European Physical Journal Plus Abbreviated Journal Eur. Phys. J. Plus
Volume 131 Issue 10 Pages 371 - 13pp
Keywords
Abstract Nuclear data in general, and neutron-induced reaction cross sections in particular, are important for a wide variety of research fields. They play a key role in the safety and criticality assessment of nuclear technology, not only for existing power reactors but also for radiation dosimetry, medical applications, the transmutation of nuclear waste, accelerator-driven systems, fuel cycle investigations and future reactor systems as in Generation IV. Applications of nuclear data are also related to research fields as the study of nuclear level densities and stellar nucleosynthesis. Simulations and calculations of nuclear technology applications largely rely on evaluated nuclear data libraries. The evaluations in these libraries are based both on experimental data and theoretical models. Experimental nuclear reaction data are compiled on a worldwide basis by the international network of Nuclear Reaction Data Centres (NRDC) in the EXFOR database. The EXFOR database forms an important link between nuclear data measurements and the evaluated data libraries. CERN's neutron time-of-flight facility nTOF has produced a considerable amount of experimental data since it has become fully operational with the start of the scientific measurement programme in 2001. While for a long period a single measurement station (EAR1) located at 185 m from the neutron production target was available, the construction of a second beam line at 20 m (EAR2) in 2014 has substantially increased the measurement capabilities of the facility. An outline of the experimental nuclear data activities at CERN's neutron time-of-flight facility nTOF will be presented.
Address [Gunsing, F.; Belloni, F.; Berthoumieux, E.; Diakaki, M.; Dupont, E.] CEA Saclay, Irfu, Gif Sur Yvette, France, Email: gunsing@cea.fr
Corporate Author Thesis
Publisher Springer Heidelberg Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2190-5444 ISBN Medium
Area Expedition Conference
Notes WOS:000386722000001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 2850
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Author Tain, J.L.; Agramunt, J.; Algora, A.; Aprahamian, A.; Cano-Ott, D.; Fraile, L.M.; Guerrero, C.; Jordan, M.D.; Mach, H.; Martinez, T.; Mendoza, E.; Mosconi, M.; Nolte, R.
Title The sensitivity of LaBr3:Ce scintillation detectors to low energy neutrons: Measurement and Monte Carlo simulation Type Journal Article
Year (down) 2015 Publication Nuclear Instruments & Methods in Physics Research A Abbreviated Journal Nucl. Instrum. Methods Phys. Res. A
Volume 774 Issue Pages 17-24
Keywords Neutron sensitivity; Scintillation detectors; Lanthanum bromide; Geant4 simulations; Nuclear data libraries
Abstract The neutron sensitivity of a cylindrical circle minus 1.5 in x 1.5 in LaBr3:Ce scintillation detector was measured using quasi-monoenergetic neutron beams in the energy range from 40 keV to 2.5 MeV. In this energy range the detector is sensitive to gamma-rays generated in neutron inelastic and capture processes. The experimental energy response was compared with Monte Carlo simulations performed with the Geant4 simulation toolkit using the so-called High Precision Neutron Models. These models rely on relevant information stored in evaluated nuclear data libraries. The performance of the Geant4 Neutron Data Library as well as several standard nuclear data libraries was investigated. In the latter case this was made possible by the use of a conversion tool that allowed the direct use of the data from other libraries in Geant4. Overall it was found that there was good agreement with experiment for some of the neutron data bases like ENDF/B-VII.0 or JENDL-3.3 but not with the others such as ENDF/B-VI.8 or JEFF-3.1.
Address [Tain, J. L.; Agramunt, J.; Algora, A.; Jordan, M. D.] Univ Valencia, CSIC, Inst Fis Corpuscular, E-28040 Valencia, Spain, Email: tain@ific.uv.es
Corporate Author Thesis
Publisher Elsevier Science Bv Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0168-9002 ISBN Medium
Area Expedition Conference
Notes WOS:000347407800003 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 2076
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Author Molina, F. et al; Rubio, B.; Agramunt, J.; Algora, A.; Domingo-Pardo, C.; Gadea, A.; Tain, J.L.
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
Year (down) 2015 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 91 Issue 1 Pages 014301 - 19pp
Keywords
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.
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
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0556-2813 ISBN Medium
Area Expedition Conference
Notes WOS:000347924300002 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 2087
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Author n_TOF Collaboration (Paradela, C. et al); Domingo-Pardo, C.; Giubrone, G.; Tain, J.L.
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
Year (down) 2015 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 91 Issue 2 Pages 024602 - 11pp
Keywords
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.
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
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0556-2813 ISBN Medium
Area Expedition Conference
Notes WOS:000350174000004 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 2139
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Author Tain, J.L. et al; Valencia, E.; Algora, A.; Agramunt, J.; Rubio, B.; Estevez, E.; Jordan, M.D.
Title Enhanced gamma-Ray Emission from Neutron Unbound States Populated in beta Decay Type Journal Article
Year (down) 2015 Publication Physical Review Letters Abbreviated Journal Phys. Rev. Lett.
Volume 115 Issue 6 Pages 062502 - 5pp
Keywords
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.
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
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0031-9007 ISBN Medium
Area Expedition Conference
Notes WOS:000359059100002 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 2319
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Author IGISOL Collaboration (Zakari-Issoufou, A.A. et al); Algora, A.; Tain, J.L.; Valencia, E.; Agramunt, J.; Estevez, E.; Gelletly, W.; Jordan, M.D.; Molina, F.; Perez-Cerdan, A.B.; Rubio, B.
Title Total Absorption Spectroscopy Study of Rb-92 Decay: A Major Contributor to Reactor Antineutrino Spectrum Shape Type Journal Article
Year (down) 2015 Publication Physical Review Letters Abbreviated Journal Phys. Rev. Lett.
Volume 115 Issue 10 Pages 102503 - 6pp
Keywords
Abstract The antineutrino spectra measured in recent experiments at reactors are inconsistent with calculations based on the conversion of integral beta spectra recorded at the ILL reactor. Rb-92 makes the dominant contribution to the reactor antineutrino spectrum in the 5-8 MeV range but its decay properties are in question. We have studied Rb-92 decay with total absorption spectroscopy. Previously unobserved beta feeding was seen in the 4.5-5.5 region and the GS to GS feeding was found to be 87.5(25)%. The impact on the reactor antineutrino spectra calculated with the summation method is shown and discussed.
Address [Zakari-Issoufou, A. -A.; Fallot, M.; Porta, A.; Bui, V. M.; Cormon, S.; Estienne, M.; Briz, J. A.; Cucoanes, A.; Shiba, T.] Univ Nantes, Ecole Mines Nantes, SUBATECH, CNRS,IN2P3, F-44307 Nantes, France, Email: porta@subatech.in2p3.fr
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0031-9007 ISBN Medium
Area Expedition Conference
Notes WOS:000360603500002 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 2375
Permanent link to this record
 

 
Author n_TOF Collaboration (Weiss, C. et al); Domingo-Pardo, C.; Tain, J.L.; Tarifeño-Saldivia, A.
Title The new vertical neutron beam line at the CERN n_TOF facility design and outlook on the performance Type Journal Article
Year (down) 2015 Publication Nuclear Instruments & Methods in Physics Research A Abbreviated Journal Nucl. Instrum. Methods Phys. Res. A
Volume 799 Issue Pages 90-98
Keywords n_TOF facility; Neutron time-of-flight; FLUKA; Neutron cross-section measurement
Abstract At the neutron Lime-of-flight facility n_TOF at CERN a new vertical beam line was constructed in 2014, in order to extend the experimental possibilities at this facility to an even wider range of challenging cross-section measurements of interest in astrophysics, nuclear technology and medical physics. The design of the beam line and the experimental hall was based on FLUKA Monte Carlo simulations, aiming at maximizing the neutron flux, reducing the beam halo and minimizing the background from neutrons interacting with the collimator or back-scattered in the beam dump. The present paper gives an overview on the design of the beam line and the relevant elements and provides an outlook on the expected performance regarding the neutron beam intensity, shape and energy resolution, as well as the neutron and photon backgrounds.
Address [Weiss, C.; Chiaveri, E.; Girod, S.; Vlachoudis, V.; Aberle, O.; Bergstroem, I.; Calviani, M.; Guerrero, C.; Sabate-Gilarte, M.; Tsinganis, A.; Brugger, M.; Cerutti, F.; Ferrari, A.; Hernandez-Prieto, A.; Kadi, Y.; Leal-Cidoncha, E.; Losito, R.; Macina, D.; Montesano, S.; Porras, I.; Rubbia, C.] CERN, European Org Nucl Res, CH-1211 Geneva, Switzerland
Corporate Author Thesis
Publisher Elsevier Science Bv Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0168-9002 ISBN Medium
Area Expedition Conference
Notes WOS:000361877300015 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 2392
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Author Estevez Aguado, M.E. et al; Algora, A.; Agramunt, J.; Rubio, B.; Tain, J.L.; Jordan, D.
Title Shapes of Pb-192, Pb-190 ground states from beta-decay studies using the total-absorption technique Type Journal Article
Year (down) 2015 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 92 Issue 4 Pages 044321 - 8pp
Keywords
Abstract The beta decay of Pb-192,Pb-190 has been studied using the total absorption technique at the ISOLDE (CERN) facility. The beta-decay strength deduced from the measurements, combined with QRPA theoretical calculations, allow us to infer that the ground states of the Pb-192,Pb-190 isotopes are spherical. These results represent the first application of the shape determination method using the total absorption technique for heavy nuclei and in a region where there is considerable interest in nuclear shapes and shape effects.
Address [Estevez Aguado, M. E.; Algora, A.; Agramunt, J.; Rubio, B.; Tain, J. L.; Jordan, D.] Univ Valencia, CSIC, IFIC, Valencia, Spain, Email: algora@ific.uv.es
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0556-2813 ISBN Medium
Area Expedition Conference
Notes WOS:000363236900003 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 2422
Permanent link to this record