Search results for "Diode"
showing 10 items of 469 documents
Hidden attractors and multistability in a modified Chua’s circuit
2021
The first hidden chaotic attractor was discovered in a dimensionless piecewise-linear Chua’s system with a special Chua’s diode. But designing such physical Chua’s circuit is a challenging task due to the distinct slopes of Chua’s diode. In this paper, a modified Chua’s circuit is implemented using a 5-segment piecewise-linear Chua’s diode. In particular, the coexisting phenomena of hidden attractors and three point attractors are noticed in the entire period-doubling bifurcation route. Attraction basins of different coexisting attractors are explored. It is demonstrated that the hidden attractors have very small basins of attraction not being connected with any fixed point. The PSIM circui…
Measurements of the stopping forces for heavy ions in Ge, Ag and Au using novel ‘polka-dot’ detectors
2006
Measurements of the stopping forces for C-14, N-14 and O-16 ions in Ge and Au, for N-14 and F-19 ions in Ag, as well as for F-19 ions in Au have been made, respectively. A novel technique, reported recently, using PIN diodes coated directly with the stopping medium in a polka dot pattern was used. This provided a set of precise, self-consistent measurements on the same stopping medium. Results show small but significant deviations from SRIM stopping predictions and are also compared to a recently-developed empirical stopping force predictor.
Radiation Tolerance Tests of Small-Sized CsI(Tl) Scintillators Coupled to Photodiodes
2009
Radiation tolerance of small-sized CsI (Tl) crystals coupled to silicon photodiodes was studied by using protons. Irradiations up to the fluence of 1012 protons/cm2 were used. Degradation of light output by less than 5% was achieved.
Electric field manipulation in Al/CdTe/Pt detectors under optical perturbations
2017
Abstract Al/CdTe/Pt detectors are very attractive devices for high-resolution X-ray spectroscopy, even though they suffer from polarization phenomena, which cause a progressive time degradation of the spectroscopic performance. In this work we investigated on the time dependence of the electric field of an Al/CdTe/Pt detector under optical perturbation by means of Pockels effect measurements. A tunable laser with wavelengths ranging within 700−1000 nm and a 940 nm light emitting diode (LED) were used. The measurements of both the electric field profile and the total current were used to better understand the effects of the optical perturbation on polarization phenomena. The results point ou…
Mass measurement of cooled neutron-deficient bismuth projectile fragments with time-resolved Schottky mass spectrometry at the FRS-ESR facility
2005
Masses of 582 neutron-deficient nuclides ($30\leq{Z}\leq{85}$) were measured with time-resolved Schottky mass spectrometry at the FRS-ESR facility at GSI, 117 were used for calibration. The masses of 71 nuclides were obtained for the first time. A typical mass accuracy of 30 $\mu$u was achieved. These data have entered the latest atomic mass evaluation. The mass determination of about 140 additional nuclides was possible via known energies ($Q$-values) of $\alpha-$, $\beta-$, or proton decays. The obtained results are compared with the results of other measurements.
Unifying Concepts for Ion-Induced Leakage Current Degradation in Silicon Carbide Schottky Power Diodes
2020
The onset of ion-induced reverse leakage current in SiC Schottky diodes is shown to depend on material properties, ion linear energy transfer (LET), and bias during irradiation, but not the voltage rating of the parts. This is demonstrated experimentally for devices from multiple manufacturers with voltage ratings from 600 to 1700 V. Using a device with a higher breakdown voltage than required in the application does not provide increased robustness related to leakage current degradation, compared to using a device with a lower voltage rating.
Ion-Induced Energy Pulse Mechanism for Single-Event Burnout in High-Voltage SiC Power MOSFETs and Junction Barrier Schottky Diodes
2020
Heavy-ion data suggest that a common mechanism is responsible for single-event burnout (SEB) in 1200-V power MOSFETs and junction barrier Schottky (JBS) diodes. Similarly, heavy-ion data suggest a common mechanism is also responsible for leakage current degradation in both devices. This mechanism, based on ion-induced, highly localized energy pulses, is demonstrated in simulations and shown to be capable of causing degradation and SEB for both the MOSFETs and JBS diodes.
Heavy Ion Induced Degradation in SiC Schottky Diodes : Bias and Energy Deposition Dependence
2017
Experimental results on ion-induced leakage current increase in 4H-SiC Schottky power diodes are presented. Monte Carlo and TCAD simulations show that degradation is due to the synergy between applied bias and ion energy deposition. This degradation is possibly related to thermal spot annealing at the metal semiconductor interface. This thermal annealing leads to an inhomogeneity of the Schottky barrier that could be responsible for the increase leakage current as a function of fluence. peerReviewed
Radiation defects in complex perovskite solid solutions
2014
Abstract First principles density functional theory (DFT) based modeling is performed to explore formation energies of a series of point cation and oxygen defects, Frenkel and Schottky disorder, as well as structural disorder in Ba1−xSrxCo1−yFeyO3−δ (BSCF) perovskite solid solutions. The results are compared with previous studies on a prototype SrTiO3 perovskite. It is shown that BSCF permits accommodation of a high concentration of defects and cation clusters but not antisite defects.
Nano-imaging of single cells using STIM
2007
Scanning transmission ion microscopy (STIM) is a technique which utilizes the energy loss of high energy (MeV) ions passing through a sample to provide structural images. In this paper, we have successfully demonstrated STIM imaging of single cells at the nano-level using the high resolution capability of the proton beam writing facility at the Centre for Ion Beam Applications, National University of Singapore. MCF-7 breast cancer cells (American Type Culture Collection [ATCC]) were seeded on to silicon nitride windows, backed by a Hamamatsu pin diode acting as a particle detector. A reasonable contrast was obtained using 1 MeV protons and excellent contrast obtained using 1 MeV alpha parti…