Analysis and characterization of materials using basic nuclear physics methods and ion beam techniques, such as: PIGE, PIXE, RBS, ERDA, resonant reactions, with emphasis on interdisciplinary works. Development of new techniques, instrumentation and methods for the characterization of materials. Accelerator mass spectrometry (AMS). Irradiation and analysis of samples using external beams.
ARTAXO NETTO, Paulo Eduardo
1) Study of atmospheric aerosols in the Amazon - we study the transport, sources and behavior of major and trace elements in the atmosphere. Through microanalysis by PIXE (Particle Induced X-Ray Emission), element concentrations are obtained and then analyzed using mathematical modeling. We carry out research in the Amazon environment, in burned-over lands, and study the effects gas and particle emissions may have in global climate. 2) Processes of deposition in the Antarctic atmosphere: We study physical and chemical processes in the Antarctic atmosphere, where we research the deposition of heavy metals. These studies in the Antarctic have contributed to the understanding of processes that regulate global atmospheric changes. 3) Physical and chemical processes of atmospheric pollution in the metropolitan area of São Paulo. We develop methods and models to predict the behavior of atmospheric pollutants in São Paulo. We also give support to the development and improvement of strategies to control pollutants in São Paulo. 4) Atmospheric radiation and global climate change - We study alterations in the atmospheric radiation balance brought about by the accumulation of particulate matter. The emissions from Amazon fires alter the spectrum of radiation reaching the soil. We develop models to study the effects and possible consequences at the global level. 5) Remote sensing of the atmosphere - We work with satellite measurements to better understand the regional mechanisms that affect the emission and transport of atmospheric pollutants on a large scale.
BARBOSA, Henrique de Melo Jorge
Parametrization of physical processes for modeling the atmospheric circulation, focusing on the areas of radiation, convection and aerosols. Aerosol-cloud interactions and climate effects. Microphysics of clouds. Radioactive forcing and climatic change. Modeling of large-scale transport of atmospheric humidity. Interaction of equatorial transport and transient systems. Effects of climatic changes on the monsoons in South America. Development of a Brazilian model for the study of global climatic change. Anomalous dispersion and anomalous diffusion in systems with Lagrangian chaos. Complex networks applied to climatic systems.
BLAK, Ana Regina
Thermally stimulated polarization and depolarization currents in isolating materials. Defects produced by ionizing radiation. Optical absorption and color centers, static computer simulations. Characterization of Brazilian crystals.
BRITO, Giancarlo Esposito de Souza
Preparation of materials from precursor sols produced through sol-gel processes and characterization of structures and structural changes from a starting solution, through the process of gelification (sol-gel transition), to the resulting xerogel (dry gel). Experimental techniques of low-angle X-ray scattering are employed. This method allows to obtain:
- Sols that can be deposited as thin films and nanostructured multilayers.
- Self-assembled mesoporous structures obtained by EISA (evaporation-induced self-assembly) which are employed in the preparation of films with periodic mesoporous structures formed through self-assembly of surfactants.
- Thin films with optical/electro-optical properties, displaying selective electrochromic absorption.
- Sols based on biocompatible iron oxide-hydroxide nanoparticles used in magnetic resonance imaging for the diagnosis of liver and spleen cancer.
X-ray absorption and diffraction techniques also used in the characterization of polycrystalline xerogel powder.
CHUBACI, José Fernando Diniz
Studies of the physical properties of natural and artificial crystals, using optical absorption (UV-VIS-NIR and FT-IR, thermoluminescence (TL), X-ray diffraction (XRD), mass spectroscopy (ICP-MS) and photoluminescence. Interaction of ionizing radiation with matter. Development of new dosimetric materials for thermoluminescence (TL), optically stimulated luminescence (OSL), radiophotoluminescence (RPL) and thermally stimulated exoelectron emission (TSEE).
Formation, modification and characterization of materials by ion beams. Ion implantation for the modification of the properties of ionic crystals and minerals. Formation of thin film by ion beam assisted deposition (IBAD): oxide films with high dielectric constant (AlOx, HfOx, TiOx), semiconductors thin films (InN), thin films for mechanical applications (TiN, BN, CN) and metallization assisted by ion beams (OLED). Computer simulation of film formation processes and the structure and properties of materials studied.
The main line of research focuses on the area of Nuclear Physics at intermediate and high energies (40 MeV to 15 TeV).
These activities are developed in Brazil, in collaboration with researchers from Rio de Janeiro-RJ, and Ilhéus-Ba, and in Switzerland through the ALICE collaboration at the Large Hadron Collider (LHC).
The main tools used in both lines of research are computer codes that use the Monte Carlo method to simulate physical processes.
In Brazil, we develop the CRISP code, which simulates nuclear reactions induced by photons (real or virtual) or baryons (protons or neutrons) in the energy range mentioned above. Here the basics of Nuclear Physics and Particle Physics are studied, and applications in Reactor Physics and Medical Physics are explored.
In the LHC, we collaborate in the development of methods for analysis and identification of particles and with data analysis. Also we study models to explain the observed phenomena. The main objective is to study the plasma of quarks and gluons, which is formed in ultra-relativistic heavy ion collisions.
Besides these two main lines, we also develop other studies where Nuclear Physics or the Monte Carlo method can be applied. Currently we are studying the behavior of RNA molecules that evolve under different conditions, observing the flow of information into the system during this evolutionary process.
JARDIM, Renato Figueiredo
Interests – Experimental Condensed Matter Physics
1) Synthesis of High TC oxides: study of their structural, magnetic, and transport properties;
2) Studies of inter and intragranular properties of High TC oxides for practical applications;
3) Metal-insulator and superconducting-insulator transitions in Cu and Ni based oxides;
4) Synthesis of magnetic nanoparticles and their general physical properties;
5) Design of supported catalysts on novel nanostructured magnetic materials and their applications in fine chemicals;
6) Novel magnetic and superconducting oxides with unconventional properties.
1) Preparation of hard thin films, for instance, of carbon nitride and boron nitride, using the method of ion beam assisted deposition (deposition on a substrate in a vacuum medium, combined with simultaneous ionic radiation). Study of the mechanism of formation of thin films with the aid of simulation programs such as TRIM (Transport of Ions in Matter) and T-DYN (Dynamic Monte-Carlo Simulation Code), and of techniques of optical absorption, hardness techniques, X-ray difratometry, transmission electron microscopy and photoelectrons induced by X-ray.
2) Study of the mechanisms of production and destruction of defects (impurities, color centers) in Brazilian minerals and synthetic crystals, by gamma radiation, light exposure and heat treatment, and its application to dating; Introduction of impurities in minerals by the methods of electrodiffusion and ion implantation; Characterization of defects using optical absorption techniques, electron spin resonance and thermoluminescence.
OLIVEIRA, Cristiano Luis Pinto de
Soft matter (proteins, polymers, surfactants), biophysics, modeling of biomolecules.
PARTITI, Carmen Silvia de Moya
Current research topics are:
1) Natural samples characterization (soils, sediments, rocks) aiming at correlating their magnetic properties with environmental parameters (environmental magnetism);
2) Nanosized iron oxides of interest in ferrofluid research;
3) Characterization of iron phosphate glasses
4) Characterization of lunar soils simulant.
RIZZUTTO, Márcia de Almeida
Study and application of methods of nuclear physics and of ion beams to the analysis and characterization of various materials and surfaces. Subjects of research: Microanalysis of biological samples such as bones, teeth, water, sediments, fish, plants, etc, by particle induced X-ray emission (PIXE). Analysis of environmental pollutants in rivers, fish, plants, and of processes of metal adsorption/absorption by plants using PIXE and SR-TXRF (synchrotron radiation total X-ray fluorescence). Analysis of light elements, such as Fluor, in water and other materials, using PIGE (Particle Induced Gamma-Ray Emission). Use of external beams to analyze various vacuum chamber incompatible materials, mainly for the analysis of works of art by the characterization of metals, pigments, and ceramics for the investigation of problems connected to historical artifacts. Analysis of metal corrosion processes. Ion implantation for the study of surfaces. Study of damage and radiation in polymers and production of ion traces for various applications. Utilization of the laboratories LAMFI and Pelletron for interdisciplinary works using the techniques PIXE, PIGE, ERDA (Elastic Recoil Detection Analyses) and RBS (Rutherford Back-Scattering).
SALVADORI, Maria Cecilia B. da Silveira
The main line of research of the Laboratory of Thin Films consists in the study of micro and nanostructure of thin films. Within this theme, the goals of our laboratory can be divided into the four following topics: (I) analysis of the nanostructured character of plasma deposited films; (II) nanoscale characterization of surfaces; (III) development of instrumentation techniques for deposition of thin films and production of micro and nanostructures; (IV) surface modifications, including by plasma treatment, micro and nanofabrication.
SANTOS, Antonio Domingues dos
My research activities are in the nanoscience and nanotechnology areas. The main objective is the development of new methods for the production and the characterization of magnetic materials on the micro and nanoscopic scales. Recent work includes:
1) Production by gas aggregation method and structural/magnetic characterization of magnetic and noble metals nanoparticles.
2) Experimental micromagnetic studies on magnetic microscopic objects by optical near-field magneto-optical methods.
3) Study of the interaction between surface plasmons and magnetism.
SILVA, Euzi C. Fernandes da
Research in the area of semiconductor materials with emphasis in the development of solid state devices (photodetectors and lasers) based on the III-V compounds operating in the infrared spectral region. The experimental characterization of the devices is performed with electrical measurements (dark current and photocurrent), transport measurements (Hall and Shubnilov-deHaas) and optical spectroscopy (FTIR, photoluminescence (PL) and photoluminescence-excitation (PLE)).
TABACNIKS, Manfredo Harri
Development of ion beam methods for modification, analysis and characterization of materials and surfaces. Some subjects of research are: Characterization of the topography of surfaces and porous structures through RBS spectroscopy; Analysis of dense samples by the PIXE method, interaction of ions and X-ray with matter; Sub-ppb trace element analysis of liquid and biological samples and samples of biomedical interest; Energetic ion implantation for the control and passivation of metallic surfaces against corrosion and oxidation. Modification of polymers through high-energy ion implantation. Physics of energetic ions (E < 1MeV) moving in matter. Stopping power, and sputtering. Production of ion tracks in insulating materials and polymers, and technological applications.
1) In 2000, a thematic project, whose objective consisted in investigating many physical properties of natural Brazilian SILICATE minerals, was approved by FAPESP. The following properties are investigated: 1) Optical absorption, 2) thermoluminescence, 3) electronic paramagnetic resonance, 4) piezo- and pyroelectricity and, 5) ionic conductivity. Since transition metals are the main impurity in those crystals, the effect of crystalline fields on the spectra of absorption and EPR are also studied. Calculation and entailment of the structure of energy bands, which have been amply conducted for alkali halides and semiconductors, will be extended to silica crystals. As silicates have a much more complex crystalline structure, a more elaborate calculation is to be expected. 2) Application of thermoluminescence studies and techniques to archeological and geological dating. Especially the dating works aiming to find when the first settlers arrived in Brazil. To the present date, the data obtained indicate that Brazil was already inhabited between 45.000 and 50.000 years ago.
YOSHIMURA, Elisabeth Mateus
Ionizing radiation dosimetry by thermoluminescence (TL) and optically stimulated luminescence (OSL): studies on dosimetric properties for the improvement of dosimeters TL and OSL; dosimetry for medical procedures. Environmental radiation (gamma and radon): development and application of methodologies for the detection of traces, gamma spectroscopy and TL, and for the assessment of population doses. Use of techniques of optical absorption, thermionic currents, and TL/OSL for the study of defects in ionic crystals. Light scattering in biological tissues and dosimetry for low-level laser therapy.
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