Maria Micaela FonsecaNew University of Lisbon -LibPhys UNL
Maria Micaela Fonseca
PhD
About
61
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Publications (61)
Although the γ-ray line emitting 25Mg(p,pγ1–0)25Mg (Eγ1–0 = 585 keV) reaction has been already studied for its relevance in nuclear structure and in material, biomedical, environmental and cultural heritage sciences, significant discrepancies exist in the data. The present paper reports on a new set of cross-section measurements for this reaction i...
Nesta era digital, e numa conjuntura social e de crise pandémica, a escola teve de se adequar às mudanças que a Covid 19 provocou, passando do ensino presencial para o ensino remoto. Segundo Nóvoa, a educação pode acontecer em qualquer lugar e a qualquer hora, tendo como referência professores reais ou virtuais. É neste enquadramento, que definimos...
A Comissão Europeia, no Plano de Ação para a Educação Digital 2021-2027. Reconfigurar a educação e a formação para a era digital (2020), sublinha a necessidade de explorar o potencial das tecnologias digitais para a aprendizagem e o ensino e desenvolver competências digitais para todos. Nesta era digital, a educação tem um papel essencial na modifi...
The applications entitled ERYA-Bulk and ERYA-Profiling (ERYA stands for Emitted Radiation Yield Analysis) are two programs which implement PIGE (Particle Induction Gamma-Ray Emission) analysis of samples which can be either homogeneous (handled by ERYA-Bulk) or heterogeneous (with multiple layers, which are simulated by ERYA-Profiling).
The homogen...
Background and aim
Evaluating the protective effect in human enamel of a fluorinated varnish after enduring a citric acid erosive challenge.
Methods
An in vitro model was developed considering the intraoral environment, human saliva and acid erosive procedures. The evaluation of the enamel specimens was undertaken through the direct analysis of en...
The present white paper provides an overview of the current discussion of game-based learning (GBL) in higher education. It begins with a brief introduction to GBL, and provides a definition for games that is representative of their use in education. A systematic literature review of GBL is then given, which highlights specific areas where further...
APRENDIZADO REMOTO: PONTOS FORTES E FRACOS?
D. Franco, M. Gonçalves
Universidade Lusófona & IPLUSO (PORTUGAL)
Com o confinamento que gerou tantos medos e tantas mudanças de hábitos em nosso cotidiano e com o agravamento da pandemia COVID-19, as escolas suspenderam, em Portugal, como de fato em escala planetária, as atividades de ensino presencial...
Digital games are unique in the sense that they are one of the few mediums that allow users to directly interact and engage with a virtual world. These worlds are often complex and filled with intertwining types of media such as: audio, 3D/2D visuals and intricate narratives; which in turn react to what the player is doing in-game. This interaction...
In recent research, games have become an important reference with regards to learning skills with certain characteristics, as well as in promoting contemporary literacies. Games have similarly become highly relevant in the promotion of psychological well-being and mental health. Even considering this role in promoting learning in general, soft skil...
The application entitled Emitted Radiation Yield Analysis (ERYA-Profiling) is a program for PIGE (Particle Induced Gamma-Ray Emission) analysis of in-depth heterogeneous samples.
Here, we present this code, which includes new features, functionalities, and direct handling of r33 and SRIM files, following the approach for a new version for ERYA-Bulk...
Ion beam analysis of fluorine has applications in research on teeth and bones, materials science, geochemistry and archaeometry. A novel PIGE (particle induced gamma-ray emission) standard free methodology for fluorine content determination for in-depth heterogeneous samples based on the excitation function of the 19F(p,p’γ)19F nuclear reaction is...
Ion beam analysis of fluorine has applications in research on teeth and bones, materials science, geochemistry and archaeometry. A novel PIGE (Particle Induced Gamma-ray Emission) standard free methodology for fluorine content determination for in-depth heterogeneous samples based on the excitation function of the ¹⁹ F(p,p’γ) ¹⁹ F nuclear reaction...
Accelerators are behind many major scientific and technological breakthroughs giving a gigantic contribution to unveil the mysteries of matter. This quest continues nowadays using the high-energy machines operating at large research centres like CERN, GANIL and FAIR, among others. Meanwhile most of the small and medium size accelerators running in...
Background: About 50% of heavy elements are produced by the slow neutron capture process (s process) in stars. The element gallium is mostly produced during the weak s process in massive stars.
PIGE has been widely used in the analysis of bulk samples, with quantification of data made usually through the use of reference samples. With a growing database of experimental cross sections becoming available, the use of first-principles data analysis methods is gaining ground. Only few codes capable of first principles analysis of PIGE data wer...
In this in vitro study, the effect of the application of tooth bleaching products in human enamel was evaluated using polarized Raman microscopy, particle induced gamma-ray emission (PIGE) and Vickers Hardness test. Due to their acidic nature, teeth whitening products are associated with changes in enamel mineralization. Consequently, products have...
Proton induced \(\gamma \)-ray reactions were used as a tool to probe and characterize a CALIFA (CALorimeter for the In-Flight detection of \(\gamma \)-rays and light charged pArticles) Barrel segment consisting of 128 CsI(Tl) crystals and readout photodetectors. In this work, we present the individual crystal response to photons from inelastic and...
In order to implement a standard free PIGE analysis of phosphorus, the cross section of the reaction ³¹P(p,pγ1-0)³¹P, γ1-0=1266.1keV was measured for the proton energy range 2.6–4 MeV, with energy steps ranging from 1 keV on resonances to 10 keV off resonance. This data provides additional information in relation to previous works on this reaction,...
Spinal cord injuries are among the most traumatic situations, having relevant repercussions on an individual’s occupation performance. Although loss of functionality is considered to be the most significant consequence, neuropathic pain can determine an individual’s inability to return to daily activities. Therefore, it is imperative to develop new...
In this work, two gustatory stimulants of salivary secretion (GSSS) were studied using Raman microscopy to evaluate their potential demineralization effect in human enamel samples and proton induced gamma‐ray emission (PIGE) to quantify fluorine uptake. These pharmaceutical products are usually administrated to patients who have revealed xerostomia...
In recent decades, the processes of fusion of ¹⁶O were studied both theoretically and experimentally. However, the theoretical calculations are unable to fit both elastic scattering cross sections and fusion S-factors.
The use of ¹⁶O thin transmission targets is required to measure the elastic forward scattering ¹⁶O + ¹⁶O reaction. The areal densit...
In this work, the cross section of the reactions ⁷Li(p,pγ)⁷Li (γ – 478 keV) at the proton energy range 2.0–4.2 MeV was measured. The measurements were carried out at the 3 MV Tandem Accelerator at the CTN/IST Laboratory in Lisbon. To validate the obtained results, calculated gamma-ray yields were compared, at several proton energy values, with expe...
Differential cross sections for proton induced γ-ray emission from the reactions 23Na(p,p'γ)²³Na (Eγ =441 and 1636keV) and ²³Na(p,α'γ)²⁰Ne (Eγ =1634keV) were measured for proton energies from 1.0 to 4.1MeV in five different ion beam laboratories. Backscattered protons were collected simultaneously for normalization purposes, avoiding the measuremen...
In the nuclear mass range A≈60 to 90 of the solar abundance distribution the weak s-process component is the dominant contributor. In this scenario, which is related to massive stars, the overall neutron exposure is not sufficient for the s process to reach mass flow equilibrium. Hence, abundances and isotopic ratios are very sensitive to the neutr...
![Figure 2. Simulated neutron spectrum with a peak energy at 25 keV [11]....](publication/319674032/figure/fig2/AS:538573355089920@1505417302850/Simulated-neutron-spectrum-with-a-peak-energy-at-25-keV-11-The-parameters-for-the_Q320.jpg)
![Figure 3. Simulated neutron spectrum with a peak energy at 90 keV [11]....](publication/319674032/figure/fig3/AS:538573355929601@1505417302915/Simulated-neutron-spectrum-with-a-peak-energy-at-90-keV-11-The-parameters-for-the_Q320.jpg)
We measured the neutron capture cross sections of 69Ga and 71Ga for a quasi-stellar spectrum at kBT = 25 keV and a spectrum with a peak energy at 90 keV by the activation technique at the Joint Research Centre (JRC) in Geel, Belgium. Protons were provided by an electrostatic Van de Graaff accelerator to produce neutrons via the reaction 7Li(p,n). T...
We have studied the high energy gamma-rays produced in the reaction $^{19}$F(p,$\alpha\gamma$)$^{16}$O for incident proton energies from 1.5 to 4.0 MeV over NaF/Ag and CaF$_2$/Ag thin targets in two different sets of data. Gamma-rays were detected with a High Purity Ge detector with an angle of 130$^{o}$ with respect to the beam axis. The cross-sec...
The nucleosynthesis of elements beyond iron is dominated by neutron captures in the s and r processes. However, 32 stable, proton-rich isotopes cannot be formed during those processes, because they are shielded from the s-process flow and r-process β-decay chains. These nuclei are attributed to the p and rp process.
For all those processes, current...
Cl is one of several short to medium lived isotopes (as compared to the earth age) whose abundances at the earlier solar system may help to clarify its formation process. There are two generally accepted possible models for the production of this radionuclide: it originated from the ejecta of a nearby supernova (where ³⁶Cl was most probably produce...
The nucleosynthesis of elements beyond iron is dominated by neutron captures in the s and r processes. However, 32 stable, proton-rich isotopes cannot be formed during those processes, because they are shielded from the s-process flow and r-process, β-decay chains. These nuclei are attributed to the p and rp process. For all those processes, curren...
The nucleosynthesis of elements beyond iron is dominated by neutron captures in the s and r processes. However, 32 stable, proton-rich isotopes cannot be formed during those processes, because they are shielded from the s-process flow and r-process, β-decay chains. These nuclei are attributed to the p and rp process. For all those processes, curren...
III-V ternary alloys semiconductor materials, in particular Ga1-x In x Sb, are ideal candidates for device substrates because of the possibility to define the lattice constant as a function of the third element, indium. Aluminum, an isoelectric dopant for Ga and In, increases the carrier mobility in GaSb crystals and has influence over the concentr...
Tantalum oxide is used in a variety of applications due to its high bandgap, high-K and high index of refraction. Unintentional impurities can change properties of tantalum oxide, and heavy ion elastic recoil detection is a method that can play a fundamental role in the quantification of those impurities. Furthermore, tantalum oxide is frequently p...
Measuring the total cross section of a fusion reaction in the region of astrophysical interest, such as the 16O+16O fusion reaction, is a real challenge due the very small cross sections involved and the large number of possible exit channels. Taking into account these difficulties, the use of targets with known thickness, stoichiometry and minimal...
Osteoporosis is the most common bone disease with severe symptoms and harmful effects on the patient quality of life. Because abnormal distribution and concentration of the major and trace elements may help to characterize the disease, ion beam analysis is applied to the study of bone samples. Proton Induced X-ray Emission and Elastic Backscatterin...
The nucleosynthesis of elements beyond iron is dominated by neutron captures
in the s and r processes. However, 32 stable, proton-rich isotopes cannot be
formed during those processes, because they are shielded from the s-process
flow and r-process beta-decay chains. These nuclei are attributed to the p and
rp process.
For all those processes, curr...
Paget Disease of Bone is a disorder characterized by abnormal bone remodeling, associated with morphological and functional abnormalities of osteoclasts although its etiology remains unproven. Ion beam analysis (IBA) techniques may be useful to characterize the abnormal distribution and concentration of the major and trace elements that can be asso...
A gold solidus of Valentinian I, Emperor of Rome (A.D. 364-375) shown in Figure 1, and belonging to a private collection, was subjected to material and stylistic analysis, in order to ascertain about its authenticity. Due to the rarity of such a coin, only non-destructive analytical techniques were used, namely Scanning Electron Microscopy (SEM), P...
The gamma-decay of the anti-analog of the giant dipole resonance (AGDR) has
been measured to the isobaric analog state excited in the p(124Sn,n) reaction
at a beam energy of 600 MeV/nucleon. The energy of the transition was also
calculated with state-of-the-art self-consistent random-phase approximation
(RPA) and turned out to be very sensitive to...
Electron screening for nuclear reactions in metals plays an unexpected and important role in enhancing reaction cross sections in the ultra-low energy region. Even though there are still some discrepancies between experimental data from different authors, the enhanced screening effect in metallic environments is well established, and attributed to...
We present the analysis performed on the chemical composition of two golden glazes available in the market using the PIGE and PIXE techniques at the ITN ion beam laboratory. The analysis of the light elements was performed using the Emitted Radiation Yield Analysis (ERYA) code, a standard-free method for PIGE analysis on thick samples. The results...
Beryllium and carbon are foreseen as materials for plasma facing components of future fusion devices. Erosion, re-deposition and thermal annealing events arising from heat-loads during reactor operation will produce mixed material layers and compounds on the plasma facing surfaces, leading to changes in the material properties. In order to mimic th...
We report an important extension to the DataFurnace code for Ion Beam Analysis which allows users to simultaneously and self-consistently analyse Rutherford (RBS) or non-Rutherford (EBS) elastic backscattering together with particle-induced gamma-ray (PIGE) spectra. We show that the code works correctly with a well-known sample. Previously it has n...
In this work, we present an alternative method for PIGE analysis of magnesium and beryllium in thick samples. This method is based on the ERYA – Emitted Radiation Yield Analysis – code, which integrates the nuclear reaction excitation function along the depth of the sample. For this purpose, the excitations functions of the 25Mg(p,p′γ)25Mg (Eγ=585k...
Very high fluence implantation of 7Li+ ions was used to promote the formation of a thin and high density 7Li target in the surface region of Al samples. The implanted volume was characterized by particle induced gamma-ray emission, Rutherford backscattering spectrometry, X-ray photoelectron spectroscopy and nuclear reaction analysis, revealing that...
In this work we present an alternative method for PIGE analysis of aluminium in thick samples. This method is based on the ERYA – emitted radiation yield analysis – code, which integrates the nuclear reaction excitation function along the depth of the sample. For this purpose, the excitations functions of the 27Al(p,p′γ1,2)27Al reaction (with gamma...
The 6Li(p,α)3He and 7Li(p,α)4He reaction cross sections were obtained for E = 90–580 keV and E = 90–1740 keV, respectively. R-matrix and polynomial fits to the bare astrophysical S-factor confirmed, with improved accuracy, previous work data, yielding Sb(0) = 3.52 ± 0.08 MeV b, and 55.6+0.8−1.7 keV b for the 6Li and 7Li reactions, respectively. The...
The aim of this work is to provide a basis for the estimation of fluorine and lithium contributions to the background of gamma-ray spectra and of their influence on PIGE (Proton-Induced Gamma-Ray Emission) detection limits of lithium, boron, fluorine and sodium. Results for yields and background contributions of lithium and fluorine were obtained f...
In the metal Cu cooled to T = 12K the α-decay half-life of 210Po nuclides, located inside the metal, was measured to be shorter by 6.3±1.4% compared to that at room temperature.
Understanding the electron screening effect in the laboratory is
critical for a correct interpretation of low-energy nuclear reactions in
stars. Extensive studies of the electron screening effect in deuterated
metals (54 metals) and other environments have been carried out in
Bochum in the last 4 years. Experimental results of anomalous
enhancement...
The electron screening in the d(d,p)t reaction has been studied for the deuterated metal Pt at a target temperature T = 20 °C to 340 °C, and for Co at T = 20 °C and 200 °C. The enhanced electron screening decreases with increasing temperature, where the data agree with the
plasma model of Debye applied to the quasi-free metallic electrons. The data...
The electron screening in the 7Li(p,α)α reaction
has been studied at E=30 to 100 keV for different
environments: Li2WO4 insulator, Li metal, and PdLi
alloys. For the insulator a screening potential energy of
U=185±150 eV was observed, consistent with previous
work and the atomic adiabatic limit. However, for the Li metal and the
PdLi alloys we find...
The electron screening in the d(d, p)t reaction has been studied for the deuterated metal Pt at a sample temperature T = 20 °C–340 °C and for Co at T = 20 °C and 200 °C. The enhanced electron screening decreases with increasing temperature, where the data agree with the plasma model of Debye applied to the quasi-free metallic electrons. The data re...
Objectives A precise knowledge of nuclear reactions cross sections (or S-factor) of light elements is crucial for the understanding of the evolution of the very early universe. Since these reactions occur in stars at very low energies (Gamow peak), with extremely low cross sections decreasing exponentially with energy, efforts to measure it at thes...
A técnica de PIGE (Emissão de radiação gama induzida por protões) foi utilizada para identificar elementos leves e determinar as suas concentrações em amostras de rochas ornamentais. A análise simultânea de elementos médios e pesados por PIXE (Emissão de radiação X induzida por protões) contribuiu para uma verificação das estruturas analisadas, nes...
Projects
Projects (8)
Enable caries diagnosis and tooth overall mineral content assessment through spectroscopic examination
This project aims to continuously improve Lusófona's undergraduate Videogames degree on two fronts:
1) By researching, implementing and validating best practices in teaching.
2) By developing novel approaches to engage and motivate students.
The end goal is to improve teaching quality and maximize the potential of students as future actors in the game development industry.
