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Author n_TOF Collaboration (Guerrero, C. et al); Domingo-Pardo, C.; Tain, J.L. doi  openurl
  Title Neutron Capture on the s-Process Branching Point Tm-171 via Time-of-Flight and Activation Type Journal Article
  Year 2020 Publication Physical Review Letters Abbreviated Journal Phys. Rev. Lett.  
  Volume 125 Issue 14 Pages 142701 - 8pp  
  Keywords  
  Abstract The neutron capture cross sections of several unstable nuclides acting as branching points in the s process are crucial for stellar nucleosynthesis studies. The unstable Tm-171 (t(1/2) = 1.92 yr) is part of the branching around mass A similar to 170 but its neutron capture cross section as a function of the neutron energy is not known to date. In this work, following the production for the first time of more than 5 mg of Tm-171 at the high-flux reactor Institut Laue-Langevin in France, a sample was produced at the Paul Scherrer Institute in Switzerland. Two complementary experiments were carried out at the neutron time-of-flight facility (nTOF) at CERN in Switzerland and at the SARAF liquid lithium target facility at Soreq Nuclear Research Center in Israel by time of flight and activation, respectively. The result of the time -of-flight experiment consists of the first ever set of resonance parameters and the corresponding average resonance parameters, allowing us to make an estimation of the Maxwellian-averaged cross sections (MACS) by extrapolation. The activation measurement provides a direct and more precise measurement of the MACS at 30 keV: 384 (40) mb, with which the estimation from the nTOF data agree at the limit of 1 standard deviation. This value is 2.6 times lower than the JEFF-3.3 and ENDF/B-VIII evaluations, 25% lower than that of the Bao et al. compilation, and 1.6 times larger than the value recommended in the KAlloNiS (v1) database, based on the only previous experiment. Our result affects the nucleosynthesis at the A similar to 170 branching, namely, the Yb-171 abundance increases in the material lost by asymptotic giant branch stars, providing a better match to the available pre-solar SiC grain measurements compared to the calculations based on the current JEFF-3.3 model-based evaluation.  
  Address [Guerrero, C.; Lerendegui-Marco, J.; Quesada, J. M.; Cortes-Giraldo, M. A.; Millan-Callado, M. A.; Praena, J.; Rodriguez-Gonzalez, T.; Sabate-Gilarte, M.] Univ Seville, Seville, Spain, Email: cguerrero4@us.es  
  Corporate Author Thesis  
  Publisher Amer Physical Soc Place of Publication Editor (up)  
  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:000574781200004 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 4551  
Permanent link to this record
 
 
Author n_TOF Collaboration (Balibrea-Correa, J. et al); Domingo-Pardo, C.; Giubrone, G.; Tain, J.L.; Tarifeño-Saldivia, A. doi  openurl
  Title Measurement of the alpha ratio and (n, gamma) cross section of U-235 from 0.2 to 200 eV at n_TOF Type Journal Article
  Year 2020 Publication Physical Review C Abbreviated Journal Phys. Rev. C  
  Volume 102 Issue 4 Pages 044615 - 18pp  
  Keywords  
  Abstract We measured the neutron capture-to-fission cross-section ratio (alpha ratio) and the capture cross section of U-235 between 0.2 and 200 eV at the nTOF facility at CERN. The simultaneous measurement of neutron-induced capture and fission rates was performed by means of the nTOF BaF2 Total Absorption Calorimeter (TAC), used for detection of gamma rays, in combination with a set of micromegas detectors used as fission tagging detectors. The energy dependence of the capture cross section was obtained with help of the Li-6(n, t) standard reaction determining the n_TOF neutron fluence; the well-known integral of the U-235(n, f) cross section between 7.8 and 11 eV was then used for its absolute normalization. The alpha ratio, obtained with slightly higher statistical fluctuations, was determined directly, without need for any reference cross section. To perform the analysis of this measurement we developed a new methodology to correct the experimentally observed effect that the probabilities of detecting a fission reaction in the TAC and the micromegas detectors are not independent. The results of this work have been used in a new evaluation of U-235 performed within the scope of the Collaborative International Evaluated Library Organisation (CIELO) Project, and are consistent with the ENDF/B-VIII.0 and JEFF-3.3 capture cross sections below 4 eV and above 100 eV. However, the measured capture cross section is on average 10% larger between 4 and 100 eV.  
  Address [Balibrea-Correa, J.; Mendoza, E.; Cano-Ott, D.] Ctr Invest Energet Medioambientales & Tecnol, CIEMAT, Madrid, Spain, Email: emilio.mendoza@ciemat.es  
  Corporate Author Thesis  
  Publisher Amer Physical Soc Place of Publication Editor (up)  
  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:000579839000003 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 4575  
Permanent link to this record
 
 
Author Guadilla, V. et al; Tain, J.L.; Algora, A.; Agramunt, J.; Jordan, D.; Monserrate, M.; Montaner-Piza, A.; Orrigo, S.E.A.; Rubio, B.; Valencia, E. url  doi
openurl 
  Title Determination of beta-decay ground state feeding of nuclei of importance for reactor applications Type Journal Article
  Year 2020 Publication Physical Review C Abbreviated Journal Phys. Rev. C  
  Volume 102 Issue 6 Pages 064304 - 12pp  
  Keywords  
  Abstract In beta-decay studies the determination of the decay probability to the ground state (g.s.) of the daughter nucleus often suffers from large systematic errors. The difficulty of the measurement is related to the absence of associated delayed gamma-ray emission. In this work we revisit the 4 pi gamma – beta method proposed by Greenwood and collaborators in the 1990s, which has the potential to overcome some of the experimental difficulties. Our interest is driven by the need to determine accurately the beta-intensity distributions of fission products that contribute significantly to the reactor decay heat and to the antineutrinos emitted by reactors. A number of such decays have large g.s. branches. The method is relevant for nuclear structure studies as well. Pertinent formulas are revised and extended to the special case of beta-delayed neutron emitters, and the robustness of the method is demonstrated with synthetic data. We apply it to a number of measured decays that serve as test cases and discuss the features of the method. Finally, we obtain g.s. feeding intensities with reduced uncertainty for four relevant decays that will allow future improvements in antineutrino spectrum and decay heat calculations using the summation method.  
  Address [Guadilla, V; Tain, J. L.; Algora, A.; Agramunt, J.; Jordan, D.; Monserrate, M.; Montaner-Piza, A.; Orrigo, S. E. A.; Rubio, B.; Valencia, E.] Univ Valencia, Inst Fis Corpuscular, CSIC, E-46071 Valencia, Spain  
  Corporate Author Thesis  
  Publisher Amer Physical Soc Place of Publication Editor (up)  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2469-9985 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000595153500001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 4626  
Permanent link to this record
 
 
Author Balibrea-Correa, J.; Lerendegui-Marco, J.; Calvo, D.; Caballero, L.; Babiano, V.; Ladarescu, I.; Redondo, M.L.; Tain, J.L.; Tolosa, A.; Domingo-Pardo, C.; Calvino, F.; Casanovas, A.; Tarifeño-Saldivia, A.; Alcayne, V.; Cano-Ott, D.; Martinez, T.; Guerrero, C.; Barbagallo, M.; Macina, D.; Bacak, M. doi  openurl
  Title A first prototype of C6D6 total-energy detector with SiPM readout for neutron capture time-of-flight experiments Type Journal Article
  Year 2021 Publication Nuclear Instruments & Methods in Physics Research A Abbreviated Journal Nucl. Instrum. Methods Phys. Res. A  
  Volume 985 Issue Pages 164709 - 8pp  
  Keywords Silicon photomultiplier; Radiation detectors; Time-of-flight; Radiative capture; Total energy detector; Pulse-height weighting technique  
  Abstract Low efficiency total-energy detectors (TEDs) are one of the main tools for neutron capture cross section measurements utilizing the time-of-flight (TOF) technique. State-of-the-art TEDs are based on a C6D6 liquid-scintillation cell optically coupled to a fast photomultiplier tube. The large photomultiplier tube represents yet a significant contribution to the so-called neutron sensitivity background, which is one of the most conspicuous sources of uncertainty in this type of experiments. Here we report on the development of a first prototype of a TED based on a silicon-photomultiplier (SiPM) readout, thus resulting in a lightweight and much more compact detector. Apart from the envisaged improvement in neutron sensitivity, the new system uses low voltage (+28 V) and low current supply (-50 mA), which is more practical than the-kV supply required by conventional photomultipliers. One important difficulty hindering the earlier implementation of SiPM readout for this type of detector was the large capacitance for the output signal when all pixels of a SiPM array are summed together. The latter leads to long pulse rise and decay times, which are not suitable for time-of-flight experiments. In this work we demonstrate the feasibility of a Schottky-diode multiplexing readout approach, that allows one to preserve the excellent timing properties of SiPMs, hereby paving the way for their implementation in future neutron TOF experiments.  
  Address [Balibrea-Correa, J.; Lerendegui-Marco, J.; Calvo, D.; Caballero, L.; Babiano, V; Ladarescu, I; Redondo, M. Lopez; Tain, J. L.; Tolosa, A.; Domingo-Pardo, C.] Univ Valencia, Inst Fis Corpuscular, CSIC, Valencia, Spain, Email: dacaldia@ific.uv.es;  
  Corporate Author Thesis  
  Publisher Elsevier Place of Publication Editor (up)  
  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:000592358200019 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 4638  
Permanent link to this record
 
 
Author Algora, A.; Tain, J.L.; Rubio, B.; Fallot, M.; Gelletly, W. url  doi
openurl 
  Title Beta-decay studies for applied and basic nuclear physics Type Journal Article
  Year 2021 Publication European Physical Journal A Abbreviated Journal Eur. Phys. J. A  
  Volume 57 Issue 3 Pages 85 - 28pp  
  Keywords  
  Abstract In this reviewwe will present the results of recent beta-decay studies using the total absorption technique that cover topics of interest for applications, nuclear structure and astrophysics. The decays studied were selected primarily because they have a large impact on the prediction of (a) the decay heat in reactors, important for the safety of present and future reactors and (b) the reactor electron anti-neutrino spectrum, of interest for particle/nuclear physics and reactor monitoring. For these studies the total absorption technique was chosen, since it is the only method that allows one to obtain beta-decay probabilities free from a systematic error called the Pandemonium effect. The total absorption technique is based on the detection of the. cascades that follow the initial beta decay. For this reason the technique requires the use of calorimeters with very high. detection efficiency. The measurements presented and discussed here were performed mainly at the IGISOL facility of the University of Jyvaskyla (Finland) using isotopically pure beams provided by the JYFLTRAP Penning trap. Examples are presented to show that the results of our measurements on selected nuclei have had a large impact on predictions of both the decay heat and the anti-neutrino spectrum from reactors. Some of the cases involve beta-delayed neutron emission thus one can study the competition between gamma – and neutron-emission from states above the neutron separation energy. The gamma-to-neutron emission ratios can be used to constrain neutron capture (n, gamma) cross sections for unstable nuclei of interest in astrophysics. The information obtained from the measurements can also be used to test nuclear model predictions of half-lives and Pn values for decays of interest in astrophysical network calculations. These comparisons also provide insights into aspects of nuclear structure in particular regions of the nuclear chart.  
  Address [Algora, A.; Tain, J. L.; Rubio, B.] Univ Valencia, CSIC, IFIC, Paterna, Spain, Email: algora@ific.uv.es  
  Corporate Author Thesis  
  Publisher Springer Place of Publication Editor (up)  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1434-6001 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000625127600001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 4754  
Permanent link to this record
 
 
Author n_TOF Collaboration (Dietz, M. et al); Domingo-Pardo, C.; Tain, J.L. doi  openurl
  Title Measurement of the Ge-72(n, y) cross section over a wide neutron energy range at the CERN n_TOF facility Type Journal Article
  Year 2021 Publication Physical Review C Abbreviated Journal Phys. Rev. C  
  Volume 103 Issue 4 Pages 045809 - 8pp  
  Keywords  
  Abstract The Ge-72(n, gamma) cross section was measured for neutron energies up to 300 keV at the neutron time-of-flight facility n_TOF (CERN), Geneva, for the first time covering energies relevant to heavy-element synthesis in stars. The measurement was performed at the high-resolution beamline EAR-1, using an isotopically enriched (GeO2)-Ge-72 sample. The prompt capture gamma rays were detected with four liquid scintillation detectors, optimized for low neutron sensitivity. We determined resonance capture kernels up to a neutron energy of 43 keV, and averaged cross sections from 43 to 300 keV. Maxwellian-averaged cross section values were calculated from kT = 5 to 100 keV, with uncertainties between 3.2% and 7.1%. The new results significantly reduce uncertainties of abundances produced in the slow neutron capture process in massive stars.  
  Address [Dietz, M.; Lederer-Woods, C.; Tattersall, A.; Battino, U.; Kahl, D.; Lonsdale, S. J.; Woods, P. J.] Univ Edinburgh, Sch Phys & Astron, Edinburgh, Midlothian, Scotland, Email: mirco.dietz@ptb.de  
  Corporate Author Thesis  
  Publisher Amer Physical Soc Place of Publication Editor (up)  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2469-9985 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000647603800002 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 4811  
Permanent link to this record
 
 
Author Hall, O. et al; Agramunt, J.; Algora, A.; Domingo-Pardo, C.; Morales, A.I.; Rubio, B.; Tain, J.L.; Tolosa-Delgado, A. doi  openurl
  Title beta-delayed neutron emission of r-process nuclei at the N=82 shell closure Type Journal Article
  Year 2021 Publication Physics Letters B Abbreviated Journal Phys. Lett. B  
  Volume 816 Issue Pages 136266 - 7pp  
  Keywords beta-delayed neutron emission; r-processimportant  
  Abstract Theoretical models of beta-delayed neutron emission are used as crucial inputs in r-process calculations. Benchmarking the predictions of these models is a challenge due to a lack of currently available experimental data. In this work the beta-delayed neutron emission probabilities of 33 nuclides in the important mass regions south and south-west of Sn-132 are presented, 16 for the first time. The measurements were performed at RIKEN using the Advanced Implantation Detector Array (AIDA) and the BRIKEN neutron detector array. The P-1n values presented constrain the predictions of theoretical models in the region, affecting the final abundance distribution of the second r-process peak at A approximate to 130.  
  Address [Hall, O.; Davinson, T.; Bruno, C. G.; Griffin, C. J.; Kahl, D.] Univ Edinburgh, Sch Phys & Astron, Edinburgh EH9 3FD, Midlothian, Scotland, Email: oscar.hall@ed.ac.uk  
  Corporate Author Thesis  
  Publisher Elsevier Place of Publication Editor (up)  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0370-2693 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000647421500016 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 4819  
Permanent link to this record
 
 
Author Dimitriou, P. et al; Tain, J.L.; Algora, A. url  doi
openurl 
  Title Development of a Reference Database for Beta-Delayed Neutron Emission Type Journal Article
  Year 2021 Publication Nuclear Data Sheets Abbreviated Journal Nucl. Data Sheets  
  Volume 173 Issue Pages 144-238  
  Keywords  
  Abstract Beta-delayed neutron emission is important for nuclear structure and astrophysics as well as for reactor applications. Significant advances in nuclear experimental techniques in the past two decades have led to a wealth of new measurements that remain to be incorporated in the databases. We report on a coordinated effort to compile and evaluate all the available beta-delayed neutron emission data. The different measurement techniques have been assessed and the data have been compared with semi-microscopic and microscopic-macroscopic models. The new microscopic database has been tested against aggregate total delayed neutron yields, time-dependent group parameters in 6-and 8-group re-presentation, and aggregate delayed neutron spectra. New recommendations of macroscopic delayed-neutron data for fissile materials of interest to applications are also presented.  
  Address [Dimitriou, P.; Verpelli, M.] IAEA, NAPC Nucl Data Sect, A-1400 Vienna, Austria, Email: p.dimitriou@iaea.org  
  Corporate Author Thesis  
  Publisher Academic Press Inc Elsevier Science Place of Publication Editor (up)  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0090-3752 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000647012500006 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 4828  
Permanent link to this record
 
 
Author n_TOF Collaboration (Gawlik, A. et al); Domingo-Pardo, C.; Tain, J.L.; Tarifeño-Saldivia, A. doi  openurl
  Title Radiative Neutron Capture Cross-Section Measurement of Ge Isotopes at n_TOF CERN Facility and Its Importance for Stellar Nucleosynthesis Type Journal Article
  Year 2021 Publication Acta Physica Polonica A Abbreviated Journal Acta Phys. Pol. A  
  Volume 139 Issue 4 Pages 383-388  
  Keywords n_TOF; neutron time-of-flight; neutron capture cross-section; MACS  
  Abstract This manuscript summarizes the results of radiative neutron capture cross-section measurements on two stable germanium isotopes, Ge-70 and Ge-73. Experiments were performed at the n_TOF facility at CERN via the time-of-flight technique, over a wide neutron energy range, for all stable germanium isotopes (70,72,73,74, and 76). Results for Ge-70 [Phys. Rev. C 100, 045804 (2019)] and Ge-73 [Phys. Lett. B 790, 458 (2019)] are already published. In the field of nuclear structure, such measurements allow to study excited levels close to the neutron binding energy and to obtain information on nuclear properties. In stellar nucleosynthesis research, neutron induced reactions on germanium are of importance for nucleosynthesis in the weak component of the slow neutron capture processes.  
  Address [Gawlik, A.; Andrzejewski, J.; Perkowski, J.] Univ Lodz, Lodz, Poland, Email: aleksandra.gawlik@uni.lodz.pl  
  Corporate Author Thesis  
  Publisher Polish Acad Sciences Inst Physics Place of Publication Editor (up)  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0587-4246 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000653413700004 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 4840  
Permanent link to this record
 
 
Author n_TOF Collaboration (Amaducci, S. et al); Babiano-Suarez, V.; Caballero-Ontanaya, L.; Domingo-Pardo, C.; Ladarescu, I.; Tain, J.L. doi  openurl
  Title First Results of the Ce-140(n,gamma)Ce-141 Cross-Section Measurement at n_TOF Type Journal Article
  Year 2021 Publication Universe Abbreviated Journal Universe  
  Volume 7 Issue 6 Pages 200 - 11pp  
  Keywords  
  Abstract An accurate measurement of the Ce-140(n,gamma) energy-dependent cross-section was performed at the n_TOF facility at CERN. This cross-section is of great importance because it represents a bottleneck for the s-process nucleosynthesis and determines to a large extent the cerium abundance in stars. The measurement was motivated by the significant difference between the cerium abundance measured in globular clusters and the value predicted by theoretical stellar models. This discrepancy can be ascribed to an overestimation of the Ce-140 capture cross-section due to a lack of accurate nuclear data. For this measurement, we used a sample of cerium oxide enriched in Ce-140 to 99.4%. The experimental apparatus consisted of four deuterated benzene liquid scintillator detectors, which allowed us to overcome the difficulties present in the previous measurements, thanks to their very low neutron sensitivity. The accurate analysis of the p-wave resonances and the calculation of their average parameters are fundamental to improve the evaluation of the Ce-140 Maxwellian-averaged cross-section.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor (up)  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000665969800001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 4877  
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