Search results for "radiation effect"
showing 10 items of 111 documents
Effect of 20 MeV Electron Radiation on Long Term Reliability of SiC Power MOSFETs
2023
The effect of 20 MeV electron radiation on the lifetime of the silicon carbide power MOSFETs was investigated. Accelerated constant voltage stress (CVS) was applied on the pristine and irradiated devices and time-to-breakdown ( T BD ) and charge-to-breakdown ( Q BD ) of gate oxide were extracted and compared. The effect of electron radiation on the device lifetime reduction can be observed at lower stress gate-to-source voltage ( V GS ) levels. The models of T BD and Q BD dependence on the initial gate current ( I G0 ) are proposed which can be used to describe the device breakdown behaviour. peerReviewed
Radiation Hardened Optical Frequency Domain Reflectometry Distributed Temperature Fiber-Based Sensors
2015
International audience; We study the performance of Optical Frequency Domain Reflectometry (OFDR) distributed temperature sensors using radiation resistant single-mode optical fibers. In situ experiments under 10 keV X-rays exposure up to 1 MGy( SiO 2 ) were carried out with an original setup that allows to investigate combined temperature and radiation effects on the sensors within a temperature range from 30 ° C to 250 ° C. Obtained results demonstrate that optical fiber sensors based on Rayleigh technique are almost unaffected by radiation up to the explored doses. We show that a pre-thermal treatment stabilize the sensor performance increasing the accuracy on temperature measurement fro…
Proton irradiation-induced reliability degradation of SiC power MOSFET
2023
The effect of 53 MeV proton irradiation on the reliability of silicon carbide power MOSFETs was investigated. Post-irradiation gate voltage stress was applied and early failures in time-dependent dielectric breakdown (TDDB) test were observed for irradiated devices. The applied drain voltage during irradiation affects the degradation probability observed by TDDB tests. Proton-induced single event burnouts (SEB) were observed for devices which were biased close to their maximum rated voltage. The secondary particle production as a result of primary proton interaction with the device material was simulated with the Geant4-based toolkit. peerReviewed
Radiation hardening techniques for rare-earth-based optical fibers and amplifiers
2012
Er/Yb doped fibers and amplifiers have been shown to be very radiation sensitive, limiting their integration in space. We present an approach including successive hardening techniques to enhance their radiation tolerance. The efficiency of our approach is demonstrated by comparing the radiation responses of optical amplifiers made with same lengths of different rare-earth doped fibers and exposed to gamma-rays. Previous studies indicated that such amplifiers suffered significant degradation for doses exceeding 10 krad. Applying our techniques significantly enhances the amplifier radiation resistance, resulting in a very limited degradation up to 50 krad. Our optimization techniques concern …
Evidence of different red emissions in irradiated germanosilicate materials
2016
International audience; This experimental investigation is focused on a radiation induced red emission in Ge doped silica materials, elaborated with different methods and processes. The differently irradiated samples as well as the pristine ones were analyzed with various spectroscopic techniques, such as confocal microscopy luminescence (CML), time resolved luminescence (TRL), photoluminescence excitation (PLE) and electron paramagnetic resonance (EPR). Our data prove that irradiation induces a red luminescence related to the presence of the Ge atoms. Such emission features a photoexcitation spectrum in the UV-blue spectral range and, TRL measurements show that its decrease differs from a …
Coupled irradiation-temperature effects on induced point defects in germanosilicate optical fibers
2017
International audience; We investigated the combined effects of temperature and X-rays exposures on the nature of point defects generated in Ge-doped multimode optical fibers. Electron paramagnetic resonance (EPR) results on samples X-ray irradiated at 5 kGy(SiO2), employing different temperatures and dose rates, are reported and discussed. The data highlight the generation of the Ge(1), Ge(2), E0 Ge and E0 Si defects. For the Ge(1) and Ge(2), we observed a decrease in the induced defect concentrations for irradiation temperatures higher than *450 K, whereas the E0 defects feature an opposite tendency. The comparison with previous post-irradiation thermal treatments reveals peculiar effects…
X-ray irradiation effects on a multistep Ge-doped silica fiber produced using different drawing conditions
2011
International audience; We report an experimental study based on confocal microscopy luminescence (CML) and electron paramagnetic resonance (EPR) measurements to investigate the effects of the X-ray (from 50 krad to 200 Mrad) on three specific multistep Ge doped fibers obtained from the same preform by changing some of the drawing conditions (tension and speed). CML data show that, both before and after the irradiation, Germanium Lone Pair Center (GLPC) concentrations are similarly distributed along the diameters of the three fibers and they are partially reduced by irradiation. The irradiation induces also the Non Bridging Oxygen Hole Center (NBOHC) investigated by CML and other paramagnet…
Influence of Drawing Conditions on the Properties and Radiation Sensitivities of Pure-Silica-Core Optical Fibers
2012
International audience; The structure and radiation sensitivities of three different pure-silica-core fluorine-doped-cladding optical fibers, made from the same original preform, were investigated by several experimental techniques. The fibers were obtained by changing the drawing speed and tension in the typical ranges of values used for the radiation-tolerant waveguides. The Raman spectroscopy revealed no significant difference among the fibers before irradiation. At variance, the comparison between the fibers and their associated preform highlighted an increase in the amplitude of the D2 band that is related to the concentration of 3 member rings. Moreover, in the zones where the D2 incr…
Adipose tissue sensitivity to radiation exposure
2008
1525-2191 (Electronic) Journal Article Research Support, Non-U.S. Gov't; Treatment of cancer using radiation can be significantly compromised by the development of severe acute and late damage to normal tissue. Treatments that either reduce the risk and severity of damage or that facilitate the healing of radiation injuries are being developed, including autologous adipose tissue grafts to repair tissue defects or involutional disorders that result from tumor resection. Adipose tissue is specialized in energy storage and contains different cell types, including preadipocytes, which could be used for autologous transplantation. It has long been considered a poorly proliferative connective ti…
MALTA: a CMOS pixel sensor with asynchronous readout for the ATLAS High-Luminosity upgrade
2018
Radiation hard silicon sensors are required for the upgrade of the ATLAS tracking detector for the High- Luminosity Large Hadron Collider (HL-LHC) at CERN. A process modification in a standard 0.18 μm CMOS imaging technology combines small, low-capacitance electrodes (∼2 fF for the sensor) with a fully depleted active sensor volume. This results in a radiation hardness promising to meet the requirements of the ATLAS ITk outer pixel layers (1.5 × 1015 neq /cm2 ), and allows to achieve a high signal-to-noise ratio and fast signal response, as required by the HL-LHC 25 ns bunch crossing structure. The radiation hardness of the charge collection to Non-Ionizing Energy Loss (NIEL) has been previ…