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Author |
n_TOF Collaboration (Mazzone, A. et al); Babiano-Suarez, V; Caballero, L.; Domingo-Pardo, C.; Ladarescu, I; Tain, J.L. |
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Title |
Measurement of the Gd-154(n, gamma) cross section and its astrophysical implications |
Type |
Journal Article |
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Year |
2020 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
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Volume |
804 |
Issue |
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Pages |
135405 - 6pp |
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Keywords  |
s process; Gd-154; Neutron time of flight; n_TOF |
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Abstract |
The neutron capture cross section of Gd-154 was measured from 1 eV to 300 keV in the experimental area located 185 m from the CERN n_TOF neutron spallation source, using a metallic sample of gadolinium, enriched to 67% in Gd-154. The capture measurement, performed with four C6D6 scintillation detectors, has been complemented by a transmission measurement performed at the GELINA time-of-flight facility (JRC-Geel), thus minimising the uncertainty related to sample composition. An accurate Maxwellian averaged capture cross section (MACS) was deduced over the temperature range of interest for s process nucleosynthesis modelling. We report a value of 880(50) mb for the MACS at kT = 30 keV, significantly lower compared to values available in literature. The new adopted Gd-154(n, gamma) cross section reduces the discrepancy between observed and calculated solar s-only isotopic abundances predicted by s-process nucleosynthesis models. |
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Address |
[Mazzone, A.; Barbagallo, M.; Colonna, N.; Damone, L. A.; Tagliente, G.; Variale, V.] Ist Nazl Fis Nucl, Bari, Italy, Email: Cristian.Massimi@bo.infn.it |
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Publisher |
Elsevier |
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Language |
English |
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Series Issue |
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Edition |
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ISSN |
0370-2693 |
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Conference |
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Notes |
WOS:000548740300022 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4464 |
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Author |
Cui, Z.F.; Zhang, J.L.; Binosi, D.; De Soto, F.; Mezrag, C.; Papavassiliou, J.; Roberts, C.D.; Rodriguez-Quintero, J.; Segovia, J.; Zafeiropoulos, S. |
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Title |
Effective charge from lattice QCD |
Type |
Journal Article |
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Year |
2020 |
Publication |
Chinese Physics C |
Abbreviated Journal |
Chin. Phys. C |
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Volume |
44 |
Issue |
8 |
Pages |
083102 - 10pp |
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Keywords |
running coupling; quantum chromodynamics; Dyson-Schwinger equations; lattice field theory; emergence of mass; confinement |
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Abstract |
Using lattice configurations for quantum chromodynamics (QCD) generated with three domain-wall fermions at a physical pion mass, we obtain a parameter-free prediction of QCD 's renormalisation-group-invariant process-independent effective charge, (alpha) over cap (k(2)). Owing to the dynamical breaking of scale invariance, evident in the emergence of a gluon mass-scale, m(0) = 0.43(1) GeV, this coupling saturates at infrared momenta: (alpha) over cap/pi = 0.97(4). Amongst other things: (alpha) over cap (k(2)) is almost identical to the process-dependent (PD) effective charge defined via the Bjorken sum rule; and also that PD charge which, employed in the one-loop evolution equations, delivers agreement between pion parton distribution functions computed at the hadronic scale and experiment. The diversity of unifying roles played by (alpha) over cap (k(2)) suggests that it is a strong candidate for that object which represents the interaction strength in QCD at any given momentum scale; and its properties support a conclusion that QCD is a mathematically well-defined quantum field theory in four dimensions. |
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Address |
[Cui, Z-F; Roberts, C. D.] Nanjing Univ, Sch Phys, Nanjing 210093, Peoples R China, Email: cdroberts@nju.edu.cn; |
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Publisher |
Iop Publishing Ltd |
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English |
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Edition |
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ISSN |
1674-1137 |
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Conference |
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Notes |
WOS:000557419600001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4495 |
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Author |
Calatayud-Jordan, J.; Candela-Juan, C.; Palma, J.D.; Pujades-Claumarchirant, M.C.; Soriano, A.; Gracia-Ochoa, M.; Vilar-Palop, J.; Vijande, J. |
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Title |
Influence of the simultaneous calibration of multiple ring dosimeters on the individual absorbed dose |
Type |
Journal Article |
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Year |
2021 |
Publication |
Journal of Radiological Protection |
Abbreviated Journal |
J. Radiol. Prot. |
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Volume |
41 |
Issue |
2 |
Pages |
384-397 |
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Keywords |
ring dosimeters; personal dosimetry; calibration; Monte Carlo; ISO 4037 |
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Abstract |
Ring dosimeters for personal dosimetry are calibrated in accredited laboratories following ISO 4037-3 guidelines. The simultaneous irradiation of multiple dosimeters would save time, but has to be carefully studied, since the scattering conditions could change and influence the absorbed dose in nearby dosimeters. Monte Carlo simulations using PENELOPE-2014 were performed to explore the need to increase the uncertainty of H-p (0.07) in the simultaneous irradiation of three and five DXT-RAD 707H-2 (Thermo Scientific) ring dosimeters with beam qualities: N-30, N-80 and N-300. Results show that the absorbed dose in each dosimeter is compatible with each of the others and with the reference simulation (a single dosimeter), with a coverage probability of 95% (k = 2). Comparison with experimental data yielded consistent results with the same coverage probability. Therefore, five ring dosimeters can be simultaneously irradiated with beam qualities ranging, at least, between N-30 and N-300 with a negligible impact on the uncertainty of H-p (0.07). |
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Address |
[Calatayud-Jordan, J.] Hosp Univ Politecn La Fe, Valencia, Spain, Email: calatayud_josjor@gva.es |
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Corporate Author |
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Publisher |
Iop Publishing Ltd |
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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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 |
0952-4746 |
ISBN |
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Conference |
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Notes |
WOS:000657114600001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ pastor @ |
Serial |
4850 |
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Author |
Ferrer-Sanchez, A.; Martin-Guerrero, J.; Ruiz de Austri, R.; Torres-Forne, A.; Font, J.A. |
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Title |
Gradient-annihilated PINNs for solving Riemann problems: Application to relativistic hydrodynamics |
Type |
Journal Article |
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Year |
2024 |
Publication |
Computer Methods in Applied Mechanics and Engineering |
Abbreviated Journal |
Comput. Meth. Appl. Mech. Eng. |
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Volume |
424 |
Issue |
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Pages |
116906 - 18pp |
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Keywords |
Riemann problem; Euler equations; Machine learning; Neural networks; Relativistic hydrodynamics |
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Abstract |
We present a novel methodology based on Physics-Informed Neural Networks (PINNs) for solving systems of partial differential equations admitting discontinuous solutions. Our method, called Gradient-Annihilated PINNs (GA-PINNs), introduces a modified loss function that forces the model to partially ignore high-gradients in the physical variables, achieved by introducing a suitable weighting function. The method relies on a set of hyperparameters that control how gradients are treated in the physical loss. The performance of our methodology is demonstrated by solving Riemann problems in special relativistic hydrodynamics, extending earlier studies with PINNs in the context of the classical Euler equations. The solutions obtained with the GA-PINN model correctly describe the propagation speeds of discontinuities and sharply capture the associated jumps. We use the relative l(2) error to compare our results with the exact solution of special relativistic Riemann problems, used as the reference ''ground truth'', and with the corresponding error obtained with a second-order, central, shock-capturing scheme. In all problems investigated, the accuracy reached by the GA-PINN model is comparable to that obtained with a shock-capturing scheme, achieving a performance superior to that of the baseline PINN algorithm in general. An additional benefit worth stressing is that our PINN-based approach sidesteps the costly recovery of the primitive variables from the state vector of conserved variables, a well-known drawback of grid-based solutions of the relativistic hydrodynamics equations. Due to its inherent generality and its ability to handle steep gradients, the GA-PINN methodology discussed in this paper could be a valuable tool to model relativistic flows in astrophysics and particle physics, characterized by the prevalence of discontinuous solutions. |
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Address |
[Ferrer-Sanchez, Antonio; Martin-Guerrero, JoseD.] ETSE UV, Elect Engn Dept, IDAL, Avgda Univ S-N, Valencia 46100, Spain, Email: Antonio.Ferrer-Sanchez@uv.es |
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Corporate Author |
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Publisher |
Elsevier Science Sa |
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 |
0045-7825 |
ISBN |
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Conference |
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Notes |
WOS:001221797400001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ pastor @ |
Serial |
6126 |
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Author |
NEXT Collaboration (Jones, B.J.P. et al); Carcel, S.; Carrion, J.V.; Diaz, J.; Martin-Albo, J.; Martinez, A.; Martinez-Vara, M.; Muñoz Vidal, J.; Novella, P.; Palmeiro, B.; Querol, M.; Romo-Luque, C.; Sorel, M.; Uson, A.; Yahlali, N. |
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Title |
The dynamics of ions on phased radio-frequency carpets in high pressure gases and application for barium tagging in xenon gas time projection chambers |
Type |
Journal Article |
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Year |
2022 |
Publication |
Nuclear Instruments & Methods in Physics Research A |
Abbreviated Journal |
Nucl. Instrum. Methods Phys. Res. A |
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Volume |
1039 |
Issue |
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Pages |
167000 - 19pp |
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Keywords |
RF carpets; Ion transport; Neutrinoless double beta decay; Barium tagging |
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Abstract |
Radio-frequency (RF) carpets with ultra-fine pitches are examined for ion transport in gases at atmospheric pressures and above. We develop new analytic and computational methods for modeling RF ion transport at densities where dynamics are strongly influenced by buffer gas collisions. An analytic description of levitating and sweeping forces from phased arrays is obtained, then thermodynamic and kinetic principles are used to calculate ion loss rates in the presence of collisions. This methodology is validated against detailed microscopic SIMION simulations. We then explore a parameter space of special interest for neutrinoless double beta decay experiments: transport of barium ions in xenon at pressures from 1 to 10 bar. Our computations account for molecular ion formation and pressure dependent mobility as well as finite temperature effects. We discuss the challenges associated with achieving suitable operating conditions, which lie beyond the capabilities of existing devices, using presently available or near-future manufacturing techniques. |
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Address |
[Hauptman, J.] Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA, Email: ben.jones@uta.edu |
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Corporate Author |
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Thesis |
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Publisher |
Elsevier |
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 |
0168-9002 |
ISBN |
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Area |
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Conference |
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Notes |
WOS:000861747900008 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5372 |
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| Permanent link to this record |
