Departamento de Física
URI permanente desta comunidadehttps://repositorio.fei.edu.br/handle/FEI/785
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20 resultados
Resultados da Pesquisa
- Evaluating the Reliability of Different Voting Schemes for Fault Tolerant Approximate Systems(2023-06-20) BALEN, T. R.; GONZALEZ, C. J.; OLIVEIRA, I. F. V.; DA ROSA JR. L. S.; SOARES, R. I.; SCHVITTZ, R. B.; ADDED, N.; MACCHIONE, E. L. A.; AGUIAR, V. A. P.; Marcilei Aparecida Guazzelli; MEDINA, N. H.; BUTZEN, P. F.© 2023, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.This work presents a study on the reliability of voters for approximate fault tolerant systems in the context of single event effects and electromagnetic interference. A first case study analyses different topologies of single-bit majority voters for logic circuits employing fault injection by simulation. In these simulations, an analysis is first performed to identify the critical diffusion areas of the physical implementation according to the voter input vector. Additionally, as a second case study, practical heavy ion experiments on different architectures of software-based approximate voters for mixed-signal applications are also presented, and the cross section of each voter is evaluated. The system comprising the voters was irradiated in two distinct experiments with an 16O ion beam, producing an effective LET at the active region of 5.5 MeV/mg/cm 2 . As a complementary study, a conducted electromagnetic interference injection was also performed, considering two distinct voting schemes. Results of the case-studies allow identifying the most tolerant voter architectures (among the studied ones) for approximate computing applications under single event effects and electromagnetic interference.
- Unsupervised machine learning application to identify single-event transients (SETs) from noise events in MOSFET transistor ionizing radiation effects(2023) ALLEGRO, P. R. P.; TOUFEN, D. L.; AGUIAR, V. A. P.; SANTOS, L. S. A.; OLIVEIRA W. N.; ADDED, N.; MEDINA, N. H.; MACCHIONE, E. L. A.; ALBERTON , S. G.; Marcilei Aparecida Guazzelli; MELO, M. A. A.; OLIVEIRA, J. A.© 2023This article presents a novel application of the k-means unsupervised machine learning algorithm to the problem of identifying single event transient (SET) events from noise during heavy-ion irradiation experiments of an electronic device. We explore the performance of the k-means algorithm by analyzing experimental datasets of SET events produced by several heavy-ions irradiations of a MOSFET transistor. Data anomalies and effectiveness of the chosen features (mean, standard deviation, skewness, and kurtosis) were investigated using the Isolation Forest and Random Forest algorithms, respectively. The results show a high capability of the K-means algorithm to identify SET events from noise using the first four statistical moments as features, allowing in the future the use of this method for in situ event detection and diagnosis without previous algorithm training or pre-analysis of the experimental data.
- Heavy-Ion-Induced Avalanche Multiplication in Low-Voltage Power VDMosfet(2021-09-13) ALBERTON. S. G.; MEDINA, N. H.; ADDED, N.; AGUIAR, V. A. P.; Marcilei Aparecida Guazzelli; Roberto Santos© 2021 IEEE.Lackner's theory for avalanche multiplication in semiconductor devices provides physical interpretation for the model parameters and obtaining them through experimental methods is necessary. In this work, the charge collection mechanisms of heavy-ion-induced avalanche multiplication in power MOSFETs are studied based on Lackner's impact ionization model. The heavy-ion-induced impact ionization coefficients were estimated by comparing collected charge values obtained from computational simulations and experimental measurements.
- Neutron-Induced Radiation Effects in UMOS Transistor(2022-01-05) ALBERTON. S. G.; BOAS, A. C. V.; MEDINA, N. H.; Marcilei Aparecida Guazzelli; AGUIAR, V. A. P.; ADDED, N.; FEDERICO, C. A.; GONZALEZ, O. L.; CAVALCANTE, T. C.; PEREIRA, E. C. F.; VAZ, R. G.© 2022 Institute of Physics Publishing. All rights reserved.Ground level electronics and avionics systems may suffer from radiation effects induced by neutrons. Neutrons can induce radiation effects in electronic devices via fusion-evaporation nuclear reactions, but few studies have been reported for technologies such as UMOSFET. In this work, estimates and experimental studies on neutron-induced radiation effects via nuclear reactions in a Si-based UMOSFET are presented. Methods for probability estimates of neutron-induced Single-Event Effects (SEEs) in Si-based power transistors and neutron beam energy measurement is presented. The energy spectrum of a UMOSFET subject to fast neutron irradiation was then compared to that of a high charge collection efficiency silicon particle detector.
- Using TRIM-SRIM code simulations to determine defect density produced in HOPG irradiated with high energy heavy ions(2022) AVANZI, L. H.; AGUIAR, V. A. P.; COSTA, K. M.; SANTARELLI, T. O.; MEDINA, N. H.; OLIVEIRA, J. R. B.; CAPPUZZELLO, F.; IAZZI, F.; CAPIROSSI, V.; PINNA, F.; CAVALLARO, M.; Marcilei Aparecida Guazzelli© 2022 Institute of Physics Publishing. All rights reserved.This work is part of the NUMEN Project (NUclear Matrix Elements for Neutrinoless double beta decay), which, among other goals, aims to measure cross-section of double charge exchange reactions (DCE). In the experiments to be carried out at the Laboratori Nazionali del Sud, in Catania, Italy, a target deposited on a carefully chosen backing (substrate) will be irradiated with a high energy ion beam and, importantly, neither the target nor the substrate will be allowed to overheat as this would affect their structures and its properties, which are special for the experiment. Within this context, highly oriented pyrolytic graphite (HOPG) was chosen as a substrate for the deposition of target elements that will be irradiated by ions such as 12C, 18O and 20Ne, with energies ranging from 15 MeV/u to 60 MeV/u. HOPG is considered a semimetal structured in layers, being composed of a stack of graphene sheets with a small and very subtle disorientation (less than 1°), which makes it to approach to a single crystal. With its specific flat hexagonal molecular structure, consisting only of carbon atoms, HOPG has good thermal conductivity in these sheets, making it an excellent candidate as a heat sink. However, for the HOPG to act with thermal energy dissipation functionality during the experiments proposed by the NUMEN project, it is necessary to verify whether possible changes caused by exposure to the radiation beam have a direct or indirect influence on its mechanical and thermal properties. Regarding the thermal conductivity, vacancies produced during irradiation is one of the factors that considerably decrease such property. As the production of vacancies during irradiation is one of the factors that considerably decrease thermal conductivity, in this work it was used the SRIM/TRIM code simulations to investigate the mechanisms of vacancy production in the target plus HOPG backing system. In the simulations, it was considered different types and doses of incident ion beams as well as different target thickness. From the results it was possible to estimated how long a target-HOPG system can be irradiated before the HOPG high heat conductivity property is lost.
- Isomeric state in the odd-odd 68Ga nucleus(2022-01-05) ESCUDEIRO, R.; VASCONCELOS, C. E. C; ALLEGRO, P. R. P.; MEDINA, N. H.; TUFEN, D. L.; ADDED, N.; AGUIAR, V. A. P.; ALBERTON. S. G. P. N.; ALCANTARA-NUNEZ, J.; Marcilei Aparecida Guazzelli; MACCHIONE. E. L. A.; OLIVEIRA, J. R. B.; RIBAS, R. V.; SCARDUELLI, V. B.© 2022 Institute of Physics Publishing. All rights reserved.The half life of the 7− isomeric state of the odd-odd 68Ga nucleus was measured using a particle-γ delayed coincidence technique. The 68Ga nuclei were produced using the fusion-evaporation reaction 55Mn(16O, 2pn)68Ga at 55 MeV incident beam energy. The beam was produced by the 8 MV Pelletron accelerator of the Nuclear Physics Open Laboratory of the University of São Paulo. The half life was measured using the Isomeric State Measurement System (SISMEI). The obtained value was 60.83(25) ns, compatible with previous measurements. The 68Ga excited states were well described with the Large Scale Shell Model using the JUN45 residual interaction.
- Charge deposition analysis of heavy-ion-induced single-event burnout in low-voltage power VDMOSFET(2022-10-05) ALBERTON, S. G.; AGUIAR, V. A. P.; MEDINA, N. H.; ADDED, N.; MACCHIONE, E. L. A.; MENEGASSO, R.; CESARIO. G. J.; SANTOS, H. C.; SCARDUELLI, V. B.; ALCANTARA-NUNEZ, J. A.; Marcilei Aparecida Guazzelli; Roberto Santos; FLECHAS, D.© 2022 Elsevier LtdThe heavy-ion-induced single-event burnout (SEB) risk in power MOSFETs (metal-oxide-semiconductor field-effect transistors) can be assessed in ground facilities, although it is costly and time-demanding. For this reason, there have been few experimental studies dedicated to investigate the relevant parameter related to the description of ion-induced SEB phenomenon. In this work the heavy-ion-induced SEB in a low-voltage power VDMOSFET (vertical double-diffused MOSFET) is studied using several ion-energy combinations. A self-consistent statistical analysis is carried out in order to elucidate the relationship between charge deposition and SEB triggering. Experimental data is compared to a predictive model from the literature for SEE (single-event effect) worst-case prediction in power MOSFETs, supporting for the first time its relevance to the worst-case prediction in the SEB mechanism.
- Testing a Fault Tolerant Mixed-Signal Design Under TID and Heavy Ions(2021-01-05) GONZALEZ, C. J.; MACHADO, D. N.; VAZ, R. G.; VILAS BOAS, A. C.; GONLALEZ, O. L.; PUCHNER, H.; ADDED, N.; MACCHIONE, E. L. A.; AGUIAR, V. A. P.; KASTENSMIDT, F. L.; MEDINA, N. H.; Marcilei Aparecida Guazzelli; BALEN, T. R.© 2021, Brazilian Microelectronics Society. All rights reserved.— This work presents results of three distinct radiation tests performed upon a fault tolerant data acquisition system comprising a design diversity redundancy technique. The first and second experiments are Total Ionizing Dose (TID) essays, comprising gamma and X-ray irradiations. The last experiment considers single event effects, in which two heavy ion irradiation campaigns are carried out. The case study system comprises three analog-to-digital converters and two software-based vot-ers, besides additional software and hardware resources used for controlling, monitoring and memory manage-ment. The applied Diversity Triple Modular Redundancy (DTMR) technique, comprises different levels of diversity (temporal and architectural). The circuit was designed in a programmable System-on-Chip (PSoC), fabricated in a 130nm CMOS technology process. Results show that the technique may increase the lifetime of the system under TID if comparing with a non-redundant implementation. Considering the heavy ions experiments the system was proved effective to tolerate 100% of the observed errors originated in the converters, while errors in the processing unit present a higher criticality. Critical errors occur-ring in one of the voters were also observed. A second heavy ion campaign was then carried out to investigate the voters reliability, comparing the the dynamic cross section of three different software-based voter schemes im-plemented in the considered PSoC.
- Absorbed gamma-ray doses due to natural radionuclides in building materials(2010-09-05) AGUIAR, V. A. P.; MEDINA, N. H.; MOREIRA, R. H.; Marcilei Aparecida GuazzelliThis work is devoted to the application of high-resolution gamma-ray spectrometry in the study of the effective dose coming from naturally occurring radionuclides, namely 40K, 232Th and 238U, present in building materials such as sand, cement, and granitic gravel. Four models were applied to estimate the effective dose and the hazard indices. The maximum estimated effective dose coming from the three reference rooms considered is 0.90(45) mSv/yr, and maximum internal hazard index is 0.77(24), both for the compact clay brick reference room. The principal gamma radiation sources are cement, sand and bricks. © 2010 American Institute of Physics.
- Effective gamma-ray doses due to natural radiation from soils of southeastern Brazil(2010-12-05) Marcilei Aparecida Guazzelli; MEDINA, N. H.; MOREIRA, R. H.; BELLINI, B. S.; AGUIAR, V. A. P.We have used gamma-ray spectrometry to study the distribution of natural radiation from soils of southeastern Brazil: Billings reservoir, São Bernardo do Campo Parks, Diadema Parks, Interlagos region, São Paulo, and soil from São Paulo and Rio de Janeiro beaches. In most of the regions studied we have found that the dose due the external exposure to gamma-rays, proceeding from natural terrestrial elements, are between the values 0.3 and 0.6 mSv/year, established by the United Nations Scientific Committee on the Effects of Atomic Radiation. © 2010 American Institute of Physics.