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A commercial off-the-shelf pMOS transistor as X-ray and heavy ion detector
(2015) Silveira M.A.G.; Melo M.A.A.; Aguiar V.A.P.; Rallo A.; Santos R.B.B.; Medina N.H.; Added N.; Seixas L.E.; Leite F.G.; Cunha F.G.; Cirne K.H.; Giacomini R.; de OLIVEIRA J.A.
© Published under licence by IOP Publishing Ltd.Recently, p-channel metal-oxide-semiconductor (pMOS) transistors were suggested as fit for the task of detecting and quantifying ionizing radiation dose. Linearity, small detection volume, fast readout, portability, low power consumption and low radiation attenuation are some of the pMOS advantages over PIN diode and thermoluminiscent dosimeters. A hand-held measurement system using a low power commercial off-the-shelf pMOSas the sensor would have a clear advantage due to the lower cost incurred by a standard technological process. In this research work, we tested the commercial device 3N163 regarding its behaviouras an X-ray sensor, as well as its possible application as a heavy-ion detector. To study the radiation effects of X-rays, a XRD-7000 (Shimadzu) X-ray diffraction setup was used to produce 10-keV effective energy photons. Heavy ions tests involved 12C, 16O, 19F, 28Si, 35Cl, 63Cu and 107Ag beams scattered at 15° by a 275 μg/cm2 gold target, which provide LETs (Linear Energy Transfer) from 4 to 40 MeV/mg/cm2. The signal readout was done using a 1 GHz oscilloscope with a 10-Gsamples/s conversion rate, high enough to permit the recording of transient pulses in the drain current. In this case, an ion can cause a current signal proportional to the ion beam used. Through this study it was found that a simple commercial pMOS device can be reliably used as a detector of X-rays as well as heavy ion detector.
A constrained analysis of the40 ca(18 o,18 f)40 k direct charge exchange reaction mechanism at 275 mev
(2021-05-05) CAVALLARO, M.; BELLONE, J. I.; CALABRESE, S.; AGODI, C.; BURRELLO, S.; CAPPUZZELLO, F.; CARBONE, D.; COLONNA, M.; DESHMUKH, N.; LENSKE, H.; SPATAFORA, A.; ACOSTA, L.; AMADOR-VALENZUELA, P.; BORELLO-LEWIN, T.; BRISCHETTO, G. A.; CALVO, D.; CAPIROSSI, V.; CHAVEZ, E.; CIRALDO, I.; CUTULI, M.; DELAUNAY, F.; DJAPO, H.; EKE, C.; FINOCCHIARO, P.; FIRAT, S.; FISICHELLA, M.; FOTI, A.; Marcilei Aparecida Guazzelli; HACISAHOGLU, A.; IAZZI, F.; FAUCI, L. L.; LINARES, R.; LUBIAN, J.; MEDINA, N. H.; MORALLES, M.; OLIVEIRA, J. R. B.; PAKOU, A.; PANDOLA, L.; PETRASCU, H.; PINNA, F.; RUSSO, G.; SGOUROS, O.; SOLAKCI, S. O.; SOUKERAS, V.; SOULIOTIS, G.; TORRESI, D.; TUDISCO, S.; YIDIRIN, A.; ZAGATTO, V. A. B.
© 2021 Cavallaro, Bellone, Calabrese, Agodi, Burrello, Cappuzzello, Carbone, Colonna, Deshmukh, Lenske, Spatafora, Acosta, Amador-Valenzuela, Borello-Lewin, Brischetto, Calvo, Capirossi, Chávez, Ciraldo, Cutuli, Delaunay, Djapo, Eke, Finocchiaro, Firat, Fisichella, Foti, Guazzelli, Hacisalihoglu, Iazzi, Fauci, Linares, Lubian, Medina, Moralles, Oliveira, Pakou, Pandola, Petrascu, Pinna, Russo, Sgouros, Solakci, Soukeras, Souliotis, Torresi, Tudisco, Yildirin and Zagatto.The40 Ca(18 O,18 F)40 K single charge exchange (SCE) reaction is explored at an incident energy of 275 MeV and analyzed consistently by collecting the elastic scattering and inelastic scattering data under the same experimental conditions. Full quantum-mechanical SCE calculations of the direct mechanism are performed by including microscopic nuclear structure inputs and adopting either a bare optical potential or a coupled channel equivalent polarization potential (CCEP) constrained by the elastic and inelastic data. The direct SCE mechanism describes the magnitude and shape of the angular distributions rather well, thus suggesting the suppression of sequential multi-nucleon transfer processes.
A focus on selected perspectives of the NUMEN project
(2022-11-09) CAVALLARO, M.; AGODI, C.; BELLONE, J. I.; BRASOLIN, S.; BRISCHETTO, G. A.; BUSSA, M. P.; CALABRESE, S.; CALVO, D.; CAMPAJOLA, L.; CAPIROSSI, V.; CAPPUZZELLO, F.; CARBONE, D.; CIRALDO, I.; COLONNA, M.; DE BENEDICTIS, C.; DE GREGORIO, G.; DELAUNAY, F.; DUMITRACHE, F.; FERRARESI, C.; FINOCCHIARO, P.; FISICHELLA, M.; GALLIAN, S.; GAMBACURTA, D.; GANDOLFO, E. M.; GARGANO, A.; GIOVANNINI, M.; IAZZI, F.; LANZALONE, G.; LAVAGNO, A.; MEREU, P.; NERI, L.; PANDOLA, L.; PANERO, R.; PERSIANI, R.; PINNA, F.; RUSSO, A. D.; RUSSO, G.; SANTOPINTO, E.; SARTIRANA, D.; SGOUROS, O.; SHAR,A, V. R.; SOUKERAS, V.; SPATAFORA, A.; TORRESI, D.; TUDISCO, S.; AVANZI, L. H.; CARDOZO, E. N.; CHINAGLIA, E. F.; COSTA, K. M.; FERREIRA, J. L.; LINARES, R.; LUBIAN, J.; MASUNAGA, S. H.; MEDINA, N. H.; MORALLES, M.; OLIVEIRA, J. R. B.; SANTARELLI, T. M.; Roberto Santos; Marcilei Aparecida Guazzelli; ZAGATTO, V. A. B.; KOULOURIS, S.; PAKOU, A.; SOULIOTIS, G.; ACOSTA, L.; AMADOR-VALENZUELA, P.; BIJKER, R.; CHAVEZ LOMELI, E. R.; GARCIA-TECOCOATZI, H.; HUERTA HERNANDEZ, A.; MARIN-LAMBARRI, D. J.; VARGA HERNANDEZ, H.; VILLAGRAN, R. G.; BOZTOSUN, I.; DAPO, H.; EKE, C.; FIRAT, S.; HACISALIHOGU, A.; KUCUK, Y.; SOLAKCI, S. O.; YILDIRIM, A.; AUERBACH, N.; BURRELLO, S.; LENSKE, H.; ISSAK, J.; PIETRALLA, N.; WERNER, V.; LAY, J. A.; PETRASCU, H.; FERRETTI, J.; KOTILA, J.; DONALDSON, L. M.; KHUMALO, T.; NEVELING. R.; PELLEGRI, L.
© 2022 Institute of Physics Publishing. All rights reserved.The use of double charge exchange reactions is discussed in view of their application to extract information that may be helpful to determinate the nuclear matrix elements entering in the expression of neutrinoless double beta decay half-life. The strategy adopted in the experimental campaigns performed at INFN - Laboratori Nazionali del Sud and in the analysis methods within the NUMEN project is briefly described, emphasizing the advantages of the multi-channel approach to nuclear reaction data analysis. An overview on the research and development activities on the MAGNEX magnetic spectrometer is also given, with a focus on the chosen technological solutions for the focal plane detector which will guarantee the performances at high-rate conditions.
A MID-INFRARED VIEW of the HIGH MASS STAR FORMATION REGION W51A
(2016) Barbosa C.L.; Blum R.D.; Damineli A.; Conti P.S.; Gusmao D.M.
© 2016. The American Astronomical Society. All rights reserved.In this paper we present the results of a mid-infrared study of G49.5-0.4, or W51A, part of the massive starbirth complex W51. Combining public data from the Spitzer IRAC camera, and Gemini mid-infrared camera T-ReCS at 7.73, 9.69, 12.33, and 24.56 μm, with a spatial resolution of ∼0.″5, we have identified the mid-infrared counterparts of eight ultracompact H ii regions, showing that two radio sources are deeply embedded in molecular clouds and another is a cloud of ionized gas. From the T-ReCS data we have unveiled the central core of the W51 region, revealing massive young stellar candidates. We modeled the spectral energy distribution of the detected sources. The results suggest that the embedded objects are sources with spectral types ranging from B3 to O5, but the majority of the fits indicate stellar objects with B1 spectral types. We also present an extinction map of IRS 2, showing that a region with lower extinction corresponds to the region where a proposed jet of gas has impacted the foreground cloud. From this map, we also derived the total extinction toward the enigmatic source IRS 2E, which amounts to ∼60 mag in the V band. We calculated the color temperature due to thermal emission of the circumstellar dust of the detected sources; the temperatures are in the interval of ∼100-150 K, which corresponds to the emission of dust located at 0.1 pc from the central source. Finally, we show a possible mid-infrared counterpart of a detected source at millimeter wavelengths that was found by Zapata et al. to be a massive young stellar object undergoing a high accretion rate.
A proposal to study long-lived isotopes produced by thermal neutron irradiation of digital devices
(2019-08-05) ZAHN, G. S.; GENEZINI, F. A; MORALLES, M.; SIQUEIRA, P. T. D.; MEDINA, N. H.; AGUIAR, V. A. P.; MACCHIONE, E. L. A.; ADDED, N.; Marcilei Aparecida Guazzelli
© Published under licence by IOP Publishing Ltd.In this work, we present a facility to study errors in digital devices exposed to thermal neutrons from a beam hole in the IEA-R1 nuclear reactor, as well as the long-lived isotopes produced in the irradiation of digital electronic devices under a slow neutron field. Preliminary results obtained with the analysis of a 28nm SRAM-based Xilinx Zynq-7000 FPGA are presented.
A system to measure isomeric state half-lives in the 10 ns to 10 μs range
(2014) Toufen D.L.; Allegro P.R.P.; Medina N.H.; Oliveira J.R.B.; Cybulska E.W.; Seale W.A.; Linares R.; Silveira M.A.G.; Ribas R.V.
The Isomeric State Measurement System (SISMEI) was developed to search for isomeric nuclear states produced by fusion-evaporation reactions. The SISMEI consists of 10 plastic phoswich telescopes, two lead shields, one NaI(Tl) scintillation detector, two Compton suppressed HPGe γ-ray detectors, and a cone with a recoil product catcher. The new system was tested at the 8 UD Pelletron tandem accelerator of the University of São Paulo with the measurement of two known isomeric states: 54Fe, 10+ state (E = 6527.1 (11) keV, T1/2 = 364(7) ns) and the 5/2+ state of 19F (E = 197.143 (4) keV, T1/2 = 89.3 (10) ns). The results indicate that the system is capable of identifying delayed transitions, of measuring isomeric state lifetimes, and of identifying the feeding transitions of the isomeric state through the delayed γ-γ coincidence method. The measured half-life for the 10+ state was T1/2 = 365(14) ns and for the 5/2+ state, 100(36) ns. © 2014 AIP Publishing LLC.
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 Guazzelli
This 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.
Amperímetro DC não invasivo utilizando sensor GMR
(2001-01-05) STEFANI FILHO, C. L.; BARBETA, V. B.
Neste trabalho apresentaremos os resultados sobre o estudo e a construção de um amperímetro para corrente contínua não invasivo, ou seja, um amperímetro que não interfere nas características do circuito sob medida. A corrente é obtida de forma indireta, através do campo magnético que ela gera ao percorrer um condutor. A intensidade do campo magnético é obtida por meio de sensores baseados no efeito de Magnetoresistência Gigante (GMR). Estes sensores são encapsulados na forma de um circuito integrado SMD e são compostos de quatro resistores ligados numa configuração de ponte de Wheatstone, sendo dois deles sensíveis ao campo magnético. Iremos ainda comparar as características de nosso sistema com outras formas de medida de corrente existentes como, por exemplo, resistência de shunt, medidor baseado em sensor de Efeito Hall e transformador de corrente.
Analog performance of standard and uniaxial strained triple-gate SOI FinFETs under x-ray radiation
(2014) Bordallo C.C.M.; Teixeira F.F.; Silveira M.A.G.; Martino J.A.; Agopian P.G.D.; Simoen E.; Claeys C.
© 2014 IOP Publishing Ltd.The influence of x-ray irradiation on the main digital and analog parameters of triple gate silicon-on- insulator FinFETs is investigated for unstrained and uniaxially strained devices. Comparing the p- and n-MuGFET response to radiation, x-rays can be more harmful for nMuGFETs than for the p-type counterparts due to the back-interface leakage current, which is generated by the positive charges trapped in the buried oxide. However, in pMuGFETs, the radiation tends to suppress the parasitic back-conduction, resulting in an improvement of the device performance.
Analysis of COTS FPGA SEU-sensitivity to combined effects of conducted-EMI and TID
(2017-07-31) VILLA, P.; BEZERRA, E.; GOERL, R.; POEHLS, L.; VARGA, F.; MEDINA N.; ADDED, N.; DE AGUIAR, V.; MACCHIORE, E.; AGUIRRE, F.; Marcilei Aparecida Guazzelli
© 2017 IEEE.The desirable use of Field-Programmable Gate Arrays (FGPAs) in aerospace & defense field has become a general consensus among IC and embedded system designers. Radiation-hardened (rad-hard) electronics used in this domain is regulated under severe and complex political and commercial treaties. In order to refrain from these undesired political and commercial barriers component-off-the-shelf (COTS) FPGAs (despite the fact of their low reliability) have been considered as a promising alternative to replace rad-hard ICs. In this scenario, this paper analyses the Single-Event Upset (SEU) sensitivity of the Microsemi ProASIC3E A3PE1500 COTS FPGA for a combined set of Electromagnetic Interference (EMI) and Total-Ionizing Dose (TID) tests. This component is under pre-qualification process for use in some satellites of the Brazilian Space Program. Experimental results are herein briefly presented and discussed. These results allow us to consider this component as a strong candidate to replace rad-hard FPGAs, if its use is combined with strict system-level fault-tolerant strategies for error detection and correction (EDAC).
Analysis of FPGA SEU sensitivity to combined effects of conducted EMI and TID
(2016-05-17) BENFICA, J.; GREEN, B.; PORCHER, B. C.; POEHLS, L. B.; VARGAS, F.; MEDINA, N. H.; ADDED, N.; AGUIAR, V. A. P. DE; MACCHIONE, E. L. A.; AGUIRRE, F.; Marcilei Aparecida Guazzelli
© 2016 IEEE.This work proposes a novel methodology to evaluate SRAM-Based FPGA SEU susceptibility to noise on VDD power pins and total-ionizing dose (TID). The procedure was demonstrated for SEU measurements on a Xilinx Spartan 3E FPGA operating in an 8MV Pelletron accelerator, whereas TID was deposited by means of a Shimadzu XRD-7000 X-ray diffractometer. The injected noise on power supply bus comprised of voltage dips of 16.67% and 25% of VDD at two different frequencies 10Hz and 5kHz, and was performed according to the IEC 61.000-4-29 international standard.
Analysis of SRAM-Based FPGA SEU Sensitivity to Combined EMI and TID-Imprinted Effects
(2016) Benfica J.; Green B.; Porcher B.C.; Poehls L.B.; Vargas F.; Medina N.H.; Added N.; De Aguiar V.A.P.; Macchione E.L.A.; Aguirre F.; Silveira M.A.G.; Perez M.; Sofo Haro M.; Sidelnik I.; Blostein J.; Lipovetzky J.; Bezerra E.A.
© 2016 IEEE.This work proposes a novel methodology to evaluate SRAM-based FPGA's susceptibility with respect to Single-Event Upset (SEU) as a function of noise on VDD power pins, Total-Ionizing Dose (TID) and TID-imprinted effect on BlockRAM cells. The proposed procedure is demonstrated for SEU measurements on a Xilinx Spartan 3E FPGA operating in an 8 MV Pelletron accelerator for the SEU test with heavy-ions, whereas TID was deposited by means of a Shimadzu XRD-7000 X-ray diffractometer. In order to observe the TID-induced imprint effect inside the BlockRAM cells, a second SEU test with neutrons was performed with Americium/Beryllium (241 AmBe). The noise was injected into the power supply bus according to the IEC 61.000-4-29 standard and consisted of voltage dips with 16.67% and 25% of the FPGA's VDD at frequencies of 10 Hz and 5 kHz, respectively. At the end of the experiment, the combined SEU failure rate, given in error/bit.day, is calculated for the FPGA's BlockRAM cells. The combined failure rate is defined as the average SEU failure rate computed before and after exposition of the FPGA to the TID.
Analysis of the one-neutron transfer reaction in O 18 + Se 76 collisions at 275 MeV
(2022) CIRALDO I.; CAPPUZZELLO, F.; CAVALLARO, M.; CARBONE, D.; BURRELLO, S.; SPATAFORA, A.; GARGANO, A.; DE GREGORIO, G.; VSEVOLODOVNA, R. I. M.; ACOSTA, L.; AGODI, C.; AMADOR-VALENZUELA, P.; BORELLO-LEWIN, T.; BRISCHETTO, G. A.; CALABRESE, S.; CALVO D.; CAPOROSSI, V.; LOMELI, E. R. C.; COLONNA, M.; DELAUNAY, F.; DJAPO, H.; EKE, C.; FINOCCHIARO, P.; FIRAT, S.; FISICHELLA, M.; FOTI, A.; HACISALIHOGLU, A.; IAZZI, F.; LA FAUCI, L.; LINARES, R.; MEDINA, N. H.; MORALES, M.; OLIVEIRA, J. R. B.; PAKOU, A.; PANDOLA, L.; PETRASCU, H.; PINNA, F.; RUSSO, G.; SANTOPINTO. E.; SGOUROS, O.; Marcilei Aparecida Guazzelli; SOLAKCI, S. O.; SOUKERAS, V.; SOULIOTIS, G.; TORRES, D.; TUDISCO, S.; YILDIRIM, A.; ZAGATTO, V. A. B.
© 2022 American Physical Society.Background: Heavy-ion one-nucleon transfer reactions are promising tools to investigate single-particle configurations in nuclear states with and without the excitation of the core degrees of freedom. A careful determination of the spectroscopic amplitudes of these configurations is essential for the accurate study of other direct reactions as well as β decays. In nucleon transfer reactions core excitations, for both target and projectile systems, are best approached via coupled-channels reaction schemes. Despite being notoriously demanding in terms of computing resources, coupled-channels analyses are progressively becoming more affordable even within model spaces large enough for tackling medium mass nuclei. In this context, the Se76(O18,O17)Se77 reaction, here under study, gives a quantitative access to the relevant single-particle orbitals and core polarization configurations built on Se76. This is particularly relevant, since it provides data-driven information to constrain nuclear structure models for Se76, which is the daughter nucleus in the Ge76 ββ decay. This reaction is one of the systems studied in the frame of the Nuclear Matrix Elements for Neutrinoless double beta decay project. Purpose: We want to analyze transitions to low-lying excited states of the residual and ejectile nuclei in the Se76(O18,O17)Se77 one-neutron stripping reaction at 275-MeV incident energy and determine the role of single-particle and core excitation in the description of the measured cross sections. In addition, we explore the sensitivity of the calculated cross section to different nuclear structure models. Methods: The excitation energy spectrum and the differential cross-section angular distributions are measured using the MAGNEX large acceptance magnetic spectrometer for the detection of the ejectiles and the missing mass technique for the reconstruction of the reaction kinematics. The data are compared with calculations based on distorted-wave Born approximation, coupled-channels Born approximation, and coupled reaction channels adopting spectroscopic amplitudes for the projectile and target overlaps derived by large-scale shell-model calculations and interacting boson-fermion model. Results: Peaks in the energy spectra corresponding to groups of unresolved transitions to Se77 and O17 are identified. The experimental cross sections are extracted and compared to theoretical calculations. A remarkable agreement is found, without using any scaling factors, demonstrating that the adopted models for nuclear structure and reaction take into account the relevant aspects of the studied processes. The main transitions which contribute to the cross section of each peak are identified. Conclusions: The coupling with the inelastic channels feeding states in entrance and exit partitions is important in the one-neutron transfer reaction and should be accounted for in future analyses of other direct reactions such as single and double charge exchange processes involving Se76 isotope. The description of Se77 indicates the need of a large model space, in the view of an accurate description of the low-lying states, a feature that should be likely accounted even for ββ-decay studies of Ge76.
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.
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.
Analyzing the influence of the angles of incidence on SEU and 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.; Marcilei Aparecida Guazzelli
© 2016 IEEE.This work highlights the impact of low LET heavy ions particles on the reliability of 28-nm Bulk SRAM cells from 4rtix-7 FPGA. Radiation tests showed significant differences in he MBU cross section of configuration (CRAM) and BRAM memory cells under various angles of incidence. Radiation results re compared with simulations at transistor level by using the ioft error tool, MUSCA SEP3 (MUlti-SCAle Single Event henomenon Prediction Platform) coupled with circuit imulations with the aim to analyze the differences of upset ensitivity as a function of layout SRAM. This analysis leads to etermine the correct layout and technology used in the tested PGA. By using the detailed classification of MBU events, it is ossible to analyze the effectiveness of correction mechanisms of he FPGA configuration memory.
Analyzing the Influence of using Reconfiguration Memory Scrubber and Hardware Redundancy in a Radiation Hardened FPGA under Heavy Ions
(2018-09-05) OLIVEIRA, A.B. DE; BENEVENUT,I F.; BENITES, L. A. C.; RODRIGUES, G. S.; KASTENSMIDT, F. L.; ADDED, N.; AGUIAR, V. A. P.; MEDINA, N. H.; Marcilei Aparecida Guazzelli; DEBARGE, C.
© 2018 IEEE.This work investigates the influence of using the built-in configuration memory scrubber and triple modular hardware redundancy in the cross section of a radiation-hardened SRAM-based FPGA from NanoXplore. Different designs versions are investigated under heavy ions for the occurrence of transient errors, failures, and timeouts. The calculated dynamic cross-sections are in agreement with the expected order of magnitude of radiation hardened SRAM-based FPGAs. Results show that the most reliable configuration is using DSPs for the operational logic and applying full design redundancy combined with scrubbing.
Anelastic spectroscopy study of the metal-insulator transition of Nd 1-xEuxNiO3
(2011) Cordero F.; Trequattrini F.; Barbeta V.B.; Jardim R.F.; Torikachvili M.S.
Measurements are presented of the complex dynamic Young's modulus of NdNiO3 and Nd0.65Eu0.35NiO3 through the metal-insulator transition (MIT). Upon cooling, the modulus presents a narrow dip at the MIT followed by an abrupt stiffening of ∼6%. The anomaly is reproducible between cooling and heating in Nd0.65Eu 0.35NiO3 but appears only as a slow stiffening during cooling in undoped NdNiO3, in conformance with the fact that the MIT in RNiO3 changes from strongly first order to second order when the mean R size is decreased. The elastic anomaly seems not to be associated with the antiferromagnetic transition, which is distinct from the MIT in Nd 0.65Eu0.35NiO3. It is concluded that the steplike stiffening is due to the disappearance or freezing of dynamic Jahn-Teller (JT) distortions through the MIT, where the JT active Ni3 + is disproportionated into alternating Ni3+δ and Ni3-δ. The fluctuating octahedral JT distortion necessary to justify the observed jump in the elastic modulus is estimated as ∼3% but does not have a role in determining the MIT, since the otherwise-expected precursor softening is not observed. © 2011 American Physical Society.
Anomalous Ferromagnetic Phase in the Gd1−xErxB4 Series: Crystal Growth, Thermal, and Magnetic Properties
(2023-07-23) MASUNAGA, S. H.; V. B. Barbeta; ABUD, F.; TORIKACHVILI, M. S.; JARDIM, R. F.
© 2023 by the authors.Rare-earth tetraborides RB4 are of great interest due to the occurrence of geometric magnetic frustration and corresponding unusual magnetic properties. While the Gd3+ spins in GdB4 align along the ab plane, Er3+ spins in the isomorphic ErB4 are confined to the c–axis. The magnetization in the latter exhibits a plateau at the midpoint of the saturation magnetization. Therefore, solid solutions of (Gd, Er)B4 provide an excellent playground for exploring the intricate magnetic behavior in these compounds. Single crystals of Gd1−xErxB4 (x = 0, 0.2, and 0.4) were grown in aluminum flux. X-ray diffraction scans revealed single-phase materials, and a drop in the unit cell volume with increasing Er content, suggesting the partial substitution of Er at the Gd sites. Heat capacity measurements indicated a systematic decrease of the Néel temperature (TN) with increasing Er content. The effective magnetic moment determined from the magnetization measurement agreed with the calculated free ion values for Gd3+ and Er3+, providing further evidence for the successful substitution of Er for Gd. The partial substitution resulted in an anomalous ferromagnetic phase below TN, exhibiting significant anisotropy, predominantly along the c-axis. This intriguing behavior merits further studies of the magnetism in the Gd1−xErxB4 borides.
Anomalous remnant magnetization in dilute antiferromagnetic
(2018) Masunaga, S. H.; BARBETA, V. B.; JARDIM, R. F.; BECERRA, C. C.; Torikachvili, M. S.; ROSA, P. F. S.; FISK, Z.

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