L. Marques
A5051753185- Nuclear Physics and Applications
- Nuclear reactor physics and engineering
- Nuclear physics research studies
- Radiation Detection and Scintillator Technologies
- Atomic and Subatomic Physics Research
- Astro and Planetary Science
- Nuclear Materials and Properties
- Radioactive contamination and transfer
- Superconducting Materials and Applications
- Advanced Frequency and Time Standards
- Radioactivity and Radon Measurements
- Radioactive element chemistry and processing
- Planetary Science and Exploration
- X-ray Spectroscopy and Fluorescence Analysis
- Radiation Therapy and Dosimetry
- Robotic Path Planning Algorithms
- Nanocluster Synthesis and Applications
- Advanced Neural Network Applications
- Robotics and Automated Systems
- High-pressure geophysics and materials
- X-ray Diffraction in Crystallography
- Trace Elements in Health
- Particle Accelerators and Free-Electron Lasers
- Astronomical and nuclear sciences
- Advanced NMR Techniques and Applications
Portuguese Military Academy
2023-2024
Portuguese Air Force Academy
2021-2023
Instituto Universitário Militar
2021-2023
Pôle Universitaire Léonard de Vinci
2009-2011
TARH (Portugal)
2010-2011
Universidad Politécnica de Madrid
2011
University of Coimbra
2010
Centre National de la Recherche Scientifique
2009
FH Campus Wien
2009
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2007-2009
The cross section of the reaction $^{197}\mathrm{Au}$($n,\ensuremath{\gamma}$) was measured with time-of-flight technique at n_TOF (neutron time-of-flight) facility in unresolved resonance region between 5 and 400 keV using a pair ${\mathrm{C}}_{6}$D${}_{6}$ (where D denotes $^{2}\mathrm{H}$) liquid scintillators for detection prompt capture $\ensuremath{\gamma}$ rays. results total uncertainty $3.9%--6.7$$%$ resolution 20 bins per energy decade show fair agreement Evaluated Nuclear Data...
We have measured the neutron capture cross sections of stable magnesium isotopes ${}^{24,25,26}$Mg in energy range interest to $s$ process using time-of-flight facility n_TOF at CERN. Capture events from a natural metal sample and samples enriched ${}^{25}$Mg ${}^{26}$Mg were recorded total method based on C${}_{6}$${}^{2}$H${}_{6}$ detectors. Neutron resonance parameters extracted by simultaneous shape analysis present data existing transmission isotopic sample. Maxwellian-averaged for...
The neutron capture cross section of $^{209}\mathrm{Bi}$ has been measured at the CERN n_TOF facility by employing pulse-height-weighting technique. Improvements over previous measurements are mainly because an optimized detection system, which led to a practically negligible sensitivity. Additional experimental sources systematic error, such as electronic threshold in detectors, summing \ensuremath{\gamma}-rays, internal electron conversion, and isomeric state bismuth, have taken into...
Neutron resonance analyses have been performed for the capture cross sections of $^{186}\mathrm{Os}$, $^{187}\mathrm{Os}$, and $^{188}\mathrm{Os}$ measured at n_TOF facility cern. Resonance parameters extracted up to 5, 3, 8 keV, respectively, using sammy code a full $R$-matrix fit yields. From these results average were derived by statistical analysis provide comprehensive experimental basis modeling stellar neutron rates isotopes in terms Hauser-Feshbach model. Consistent calculations...
Neutron-induced fission cross sections for ${}^{\text{nat}}$Pb and $^{209}\mathrm{Bi}$ were measured with a white-spectrum neutron source at the CERN Neutron Time-of-Flight (n_TOF) facility. The experiment, using neutrons from threshold up to 1 GeV, provides first results these nuclei above 200 MeV. relative $^{235}\mathrm{U}$ $^{238}\mathrm{U}$ in dedicated chamber parallel plate avalanche counter detectors. Results are compared previous experimental data. Upgraded parametrizations of...
Improving the accuracy of radiation source localization is crucial in Security and Safety scenarios. Conventional methods for detecting identifying special nuclear materials or other radioactive sources at some airports, land borders seaports, normally involve large fixed detection systems such as portal monitors, which are expensive not widespread. While handheld equipment used to confirm alarms triggered by primary inspection systems, these inspections often time-consuming. In this study,...
We have measured the neutron capture reaction yield of $^{232}\mathrm{Th}$ at time-of-flight facility n_TOF CERN in energy range from 1 eV to MeV. The average cross section has been extracted 4 keV up MeV with an overall accuracy better than 4%. An independent IAEA evaluation shows good agreement data. expressed terms resonance parameters using partial waves $\ensuremath{\ell}=0,1,$ and 2.
The precise determination of the neutron capture cross sections $^{186}\mathrm{Os}$ and $^{187}\mathrm{Os}$ is important to define $s$-process abundance at formation solar system. This quantity can be used evaluate radiogenic component due decay unstable $^{187}\mathrm{Re}$ (${t}_{1/2}=41.2$ Gyr) from this infer time duration nucleosynthesis in our galaxy (Re/Os cosmochronometer). $^{186}\mathrm{Os}$, $^{187}\mathrm{Os}$, $^{188}\mathrm{Os}$ have been measured CERN n_TOF facility 1 eV MeV,...
Background:The design of new nuclear reactors and transmutation devices requires to reduce the present neutron cross section uncertainties minor actinides. Purpose: Reduce $^{243}$Am(n,$\gamma$) uncertainty. Method: The has been measured at n_TOF facility CERN with a BaF$_{2}$ Total Absorption Calorimeter, in energy range between 0.7 eV 2.5 keV. Results: successfully mentioned range. resolved resonance region extended from 250 up 400 eV. In unresolved our results are compatible one two...
The yield of the neutron capture reaction ${}^{232}$Th($n,\ensuremath{\gamma}$) has been measured at time-of-flight facility n_TOF CERN in energy range from 1 eV to MeV. reduction acquired data for resolved resonances 4 keV is described and compared a recent evaluated set. resonance parameters were used assign an orbital momentum each resonance. A missing level estimator was extract $s$-wave spacing ${D}_{0}=17.2\ifmmode\pm\else\textpm\fi{}0.9$ eV.
The neutron capture cross section of ${}^{237}$Np was measured between 0.7 and 500 eV at the CERN n_TOF facility using 4$\ensuremath{\pi}$ BaF${}_{2}$ Total Absorption Calorimeter. experimental yield extracted minimizing all systematic uncertainties analyzed together with most reliable transmission data available sammy code. result is a complete set individual as well average resonance parameters [${D}_{0}=0.56(2)$ eV,...
The nuclear resonance parameters and the capture cross section of neutron magic isotope $^{139}\mathrm{La}$ have been measured relative to $^{197}\mathrm{Au}$ in energy range 0.6 eV 9 keV at time-of-flight (n_TOF) facility CERN. We describe experimental apparatus data analysis procedures, which concerned mainly efficiency correction by means pulse height weighting function technique determination different background components. extracted main quantities such as integral...
In order to detect special nuclear materials and other radioactive in Security Defense scenarios, normally, a combination of neutron gamma-ray detection systems is used. particular, avoid illicit traffic sources/materials, radiation portal monitors are placed at seaports inspect shipping-container cargo. Despite their large volume (high efficiency), these expensive, therefore only fraction containers inspected. this work, novel mobile system presented, based on an EJ-200 plastic scintillator...
The neutron-induced fission cross section of $^{234}\mathrm{U}$ has been measured at the CERN n_TOF facility relative to standard $^{235}\mathrm{U}$ from 20 keV 1.4 MeV and $^{238}\mathrm{U}$ 200 MeV. A fast ionization chamber (FIC) was used as a fragment detector with detection efficiency no less than 97%. high instantaneous flux low background characterizing resulted in wide-energy-range data (0.02 MeV), energy resolution, statistics, systematic uncertainties bellow 3%. Previous...
The neutron-induced fission cross section of 237Np was experimentally determined at the high-resolution and high-intensity facility n_TOF, CERN, in energy range 100 keV to 9 MeV, using 235U(n,f) 238U(n,f) standards below above 2 respectively. A fast ionization chamber used order detect fragments from reactions targets were characterized as far their mass homogeneity are concerned by means α spectroscopy Rutherford backscattering Theoretical calculations within Hauser-Feshbach formalism have...
The neutron-induced fission cross section of ${}^{236}$U was measured at the neutron Time-of-Flight (n_TOF) facility CERN relative to standard ${}^{235}$U($n$,$f$) for energies ranging from above thermal several MeV. measurement, covering full range simultaneously, performed with a fast ionization chamber, taking advantage high resolution n_TOF spectrometer. results confirm that first resonance 5.45 eV is largely overestimated in some nuclear data libraries. triplet around 1.2 keV and...
In Nuclear Security scenarios, traditional radiation portal monitors are normally fixed, large, and expensive equipment. This study introduces an innovative, cost-effective solution: a lightweight, compact, mobile gamma-ray/beta neutron detection system, comprising two plastic scintillators with silicon photomultipliers. Designed for inspecting maritime containers, real-time gamma-ray source search algorithm operates during perimeter scans. Using maximum likelihood estimation, the computes...