Departamento de Física
URI permanente desta comunidadehttps://repositorio.fei.edu.br/handle/FEI/785
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21 resultados
Resultados da Pesquisa
- Soil analysis using the semi-parametric NAA technique(2007) Zamboni C.B.; Marcilei Aparecida Guazzelli; Medina N.H.The semi-parametric Neutron Activation Analysis technique, using Au as a flux monitor, was applied to measure element concentrations of Br, Ca, Cl, K, Mn and Na for soil characterization. The results were compared with those using the Instrumental Neutron Activation Analysis technique and they found to be compatible. The viability, advantages, and limitations of using these two analytic methodologies are discussed. © 2007 American Institute of Physics.
- Shell model description of the odd-odd Co and Cu nuclei(2007-05-11) Medina N.H.; Marcilei Aparecida Guazzelli; Allegro P.R.P.; De Oliveira J.R.B.; Ribas R.V.; Seale W.A.; Toufen D.L.The known excited states of the odd-odd nuclei 54,56,58,60Co and 60,62,64,66Cu were interpreted in the framework of the large scale shell model (LSSM), using several effective interactions and configuration spaces. For the description of the negative parity states, we have allowed one particle excitation to the g9/2 orbital. The LSSM using the GXPF1 effective interaction reproduces well the first excited states in all of these nuclei. © 2007 American Institute of Physics.
- Reliability calculation with respect to functional failures induced by radiation in TMR arm cortex-M0 soft-core embedded into SRAM-based FPGA(2019) Benites L.A.C.; Benevenuti F.; De Oliveira A.B.; Kastensmidt F.L.; Added N.; Aguiar V.A.P.; Medina N.H.; Guazzelli M.A.© 2019 IEEE.This paper presents comparative results from fault injection (FI) and heavy ions accelerated irradiation on a Xilinx 7 series static RAM (SRAM)-based field-programmable gate array (FPGA) for a soft-core microprocessor mitigated by triple modular redundancy (TMR) with different levels of granularity. The Arm Cortex-M0 soft-core processor executing two software applications is employed as a case study. The TMR implementation is automatically generated from synthesized netlist and includes coarse and fine grain variants. Apart from the TMR mitigation, the configuration memory scrubbing is used as implemented by the engine natively available on Xilinx 7 series FPGAs. Experiments with FI and heavy ions allow analyzing the effectiveness of the automated TMR mitigation combined with memory scrubbing and also to analyze the consistency of reliability metrics from FI and heavy ions. The dynamic cross section of the design was improved up to 4.5 times according to the implemented TMR granularity and when associated with the configuration memory scrubbing.
- Reliability-Performance Analysis of Hardware and Software Co-Designs in SRAM-Based APSoCs(2018) Tambara L.A.; Kastensmidt F.L.; Rech P.; Lins F.; Medina N.H.; Added N.; Aguiar V.A.P.; Silveira M.A.G.© 1963-2012 IEEE.All programmable system-on-chip (APSoC) devices provide higher system performance and programmable flexibility at lower costs compared to standalone field-programmable gate array devices and processors. Unfortunately, it has been demonstrated that the high complexity and density of APSoCs increase the system's susceptibility to radiation-induced errors. This paper investigates the effects of soft errors on APSoCs at design level through reliability and performance analyses. We explore 28 different hardware and software co-designs varying the workload distribution between hardware and software. We also propose a reliability analysis flow based on fault injection (FI) to estimate the reliability trend of hardware-only and software-only designs and hardware-software co-designs. Results obtained from both radiation experiments and FI campaigns reveal that performance and reliability can be improved up to 117× by offloading the workload of an APSoC-based system to its programmable logic core. We also show that the proposed flow is a precise method to estimate the reliability trend of system designs on APSoCs before radiation experiments.
- Analyzing the Influence of the Angles of Incidence and Rotation on MBU Events Induced by Low LET Heavy Ions in a 28-nm SRAM-Based FPGA(2017) Tonfat J.; Kastensmidt F.L.; Artola L.; Hubert G.; Medina N.H.; Added N.; Aguiar V.A.P.; Aguirre F.; Macchione E.L.A.; Silveira M.A.G.© 1963-2012 IEEE.This paper shows the impact of low linear energy transfer heavy ions on the reliability of 28-nm Bulk static random access memory (RAM) cells from Artix-7 field-programmable gate array. Irradiation tests on the ground showed significant differences in the multiple bit upset cross section of configuration RAM and block RAM memory cells under various angles of incidence and rotation of the device. Experimental data are analyzed at transistor level by using the single-event effect prediction tool called multiscale single-event phenomenon prediction platform coupled with SPICE simulations.
- Extraction of natural radionuclides in TENORM waste phosphogypsum(2018) Moreira R.H.; Queiroga F.S.; Paiva H.A.; Medina N.H.; Fontana G.; Guazzelli M.A.© 2018 Published by Elsevier Ltd.Phosphate ore is the raw material for the production of fertilizers. Phosphogypsum with a high content of natural radionuclides, specifically those present in the decay series of 238U and 232Th, is a byproduct (waste material) of a chemical reaction between sulfuric acid and phosphate rock in phosphoric acid production. Due to these characteristics, the phosphogypsum is considered a TENORM (Technologically Enhanced Naturally Occurring Radioactive Materials). For each ton of phosphoric acid produced, 4 to 5 tons of phosphogypsum are generated, representing a great environmental liability. Because of the similar chemical properties of phosphogypsum and conventional gypsum, both calcium sulfate, there is a great interest in the scientific community to find technological solutions for reuse of this material. This study aimed to develop methodologies and processes for separating calcium sulfate from the main radionuclides present in the phosphogypsum, based on the difference in solubility between these compounds, among them the radium sulfate. Chemical processes were developed for the recovery of the calcium sulphate in the solid form from the extraction of the radionuclides made by dissolution of the phosphogypsum. This study shows that it is possible to extract radionuclides from waste TENORM - phosphogypsum - obtaining more than 80% of the material in the form of hydrated gypsum. Using gamma-ray spectrometry technique, no signal was detected for the presence of radionuclides in the treated material. The results indicate the benefits that the process used in this work can provide when implemented on an industrial scale.
- Electronic stopping power of Ti, V and Cr ions in Ge and Au at 150–500 keV/u energies(2017) Linares R.; Ribas R.V.; Oliveira J.R.B.; Medina N.H.; Santos H.C.; Seabra C.C.; Sigaud L.; Cybulska E.W.; Seale W.A.; Allegro P.R.P.; Touffen D.L.; Silveira M.A.G.© 2017 Elsevier B.V.In this paper new experimental data are presented for the stopping power of Ti, V and Cr ions in Ge and Au, in the 150–500 keV/u energy range. The heavy ions at low energies are produced from the elastic scattering between particles of an energetic primary beam (28Si and 16O) directed onto the primary foil of interest (Ti, V or Cr). Measurements were performed using the transmission method. New experimental data points for the stopping power of Ti in Au were compared with previous measurement. The agreement between these two datasets indicates the consistence of the experimental technique. Our experimental data were also compared to some selected theoretical and semi-empirical methods: i) the Unitary Convolution Approximation, ii) the Binary theory, iii) the SRIM code and iv) the Northcliffe & Schilling tables. The experimental data for Ge foil deviate from the theoretical curves possibly due to the effect of band gap structure of the material in the electronic stopping power. For the systems measured here, we observe that the Binary theory exhibits an overall good agreement. The velocity-proportional dependence of the electronic stopping power in the measured energy range is also discussed.
- Analyzing Reliability and Performance Trade-Offs of HLS-Based Designs in SRAM-Based FPGAs under Soft Errors(2017) Tambara L.A.; Tonfat J.; Santos A.; Kastensmidt F.L.; Medina N.H.; Added N.; Aguiar V.A.P.; Aguirre F.; Silveira M.A.G.© 1963-2012 IEEE.The increasing system complexity of FPGA-based hardware designs and shortening of time-to-market have motivated the adoption of new designing methodologies focused on addressing the current need for high-performance circuits. High-Level Synthesis (HLS) tools can generate Register Transfer Level (RTL) designs from high-level software programming languages. These tools have evolved significantly in recent years, providing optimized RTL designs, which can serve the needs of safety-critical applications that require both high performance and high reliability levels. However, a reliability evaluation of HLS-based designs under soft errors has not yet been presented. In this work, the trade-offs of different HLS-based designs in terms of reliability, resource utilization, and performance are investigated by analyzing their behavior under soft errors and comparing them to a standard processor-based implementation in an SRAM-based FPGA. Results obtained from fault injection campaigns and radiation experiments show that it is possible to increase the performance of a processor-based system up to 5,000 times by changing its architecture with a small impact in the cross section (increasing up to 8 times), and still increasing the Mean Workload Between Failures (MWBF) of the system.
- The NUMEN project: NUclear Matrix Elements for Neutrinoless double beta decay(2018) Cappuzzello F.; Agodi C.; Cavallaro M.; Carbone D.; Tudisco S.; Lo Presti D.; Oliveira J.R.B.; Finocchiaro P.; Colonna M.; Rifuggiato D.; Calabretta L.; Calvo D.; Pandola L.; Acosta L.; Auerbach N.; Bellone J.; Bijker R.; Bonanno D.; Bongiovanni D.; Borello-Lewin T.; Boztosun I.; Brunasso O.; Burrello S.; Calabrese S.; Calanna A.; Chavez Lomeli E.R.; D'Agostino G.; De Faria P.N.; De Geronimo G.; Delaunay F.; Deshmukh N.; Ferreira J.L.; Fisichella M.; Foti A.; Gallo G.; Garcia-Tecocoatzi H.; Greco V.; Hacisalihoglu A.; Iazzi F.; Introzzi R.; Lanzalone G.; Lay J.A.; La Via F.; Lenske H.; Linares R.; Litrico G.; Longhitano F.; Lubian J.; Medina N.H.; Mendes D.R.; Moralles M.; Muoio A.; Pakou A.; Petrascu H.; Pinna F.; Reito S.; Russo A.D.; Russo G.; Santagati G.; Santopinto E.; Santos R.B.B.; Sgouros O.; da Silveira M.A.G.; Solakci S.O.; Souliotis G.; Soukeras V.; Spatafora A.; Torresi D.; Magana Vsevolodovna R.; Yildirim A.; Zagatto V.A.B.© 2018, SIF, Springer-Verlag GmbH Germany, part of Springer Nature.The article describes the main achievements of the NUMEN project together with an updated and detailed overview of the related R&D activities and theoretical developments. NUMEN proposes an innovative technique to access the nuclear matrix elements entering the expression of the lifetime of the double beta decay by cross section measurements of heavy-ion induced Double Charge Exchange (DCE) reactions. Despite the fact that the two processes, namely neutrinoless double beta decay and DCE reactions, are triggered by the weak and strong interaction respectively, important analogies are suggested. The basic point is the coincidence of the initial and final state many-body wave functions in the two types of processes and the formal similarity of the transition operators. First experimental results obtained at the INFN-LNS laboratory for the 40Ca(18O,18Ne)40Ar reaction at 270MeV give an encouraging indication on the capability of the proposed technique to access relevant quantitative information. The main experimental tools for this project are the K800 Superconducting Cyclotron and MAGNEX spectrometer. The former is used for the acceleration of the required high resolution and low emittance heavy-ion beams and the latter is the large acceptance magnetic spectrometer for the detection of the ejectiles. The use of the high-order trajectory reconstruction technique, implemented in MAGNEX, allows to reach the experimental resolution and sensitivity required for the accurate measurement of the DCE cross sections at forward angles. However, the tiny values of such cross sections and the resolution requirements demand beam intensities much larger than those manageable with the present facility. The on-going upgrade of the INFN-LNS facilities in this perspective is part of the NUMEN project and will be discussed in the article.
- Portable X-ray fluorescence system to measure Th and U concentrations(2018) Guazzelli da Silveira M.A.; Pereira B.R.; Medina N.H.; Rizzutto M.A.© 2018 Elsevier LtdThis study reports the results obtained in the analysis of waste material samples generated by the industries of phosphate fertilizers, in particular, the use of specific filters in a portable X-ray fluorescence system, a simple equipment allowing the characterization, identification and quantification of low concentrations of Th and U (ppm). The industrial byproduct is classified as a Technologically-Enhanced, Naturally-Occurring Radioactive Material - TENORM, and therefore requires monitoring for its radio-toxic activity due to the presence of radioactive thorium and uranium families. From the results obtained, it is concluded that this technique is able to determine the contents of these elements to concentrations of tens of ppm in measurements of about 300 s, and a small sample amount (∼0.1 g).
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