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The experiments of the pinned photodiode complementary metal–oxide–semiconductor (CMOS) image sensors irradiated by 60Co $\gamma $ rays, neutrons, and protons are presented. The CMOS image sensors are manufactured using a standard 0.18- $\mu \text{m}$ CMOS technology with 4 MP. The fixed pattern noise (FPN) and temporal noise versus the total doses at different dose rates are analyzed. The FPN and temporal noise degradations induced by 60Co $\gamma $ rays with different biased conditions are compared. The FPN and temporal noise degradations induced by displacement damage are also investigated by proton and neutron radiation. The degradation mechanisms of the FPN and temporal noise induced by 60Co $\gamma $ ray, neutron, and proton radiation are analyzed. [ABSTRACT FROM AUTHOR]

The scintillation anisotropy effect for proton recoil events has been investigated in five pure organic crystalline materials: anthracene, trans-stilbene, p-terphenyl, bibenzyl, and diphenylacetylene (DPAC). These measurements include the characterization of the scintillation response for one hemisphere of proton recoil directions in each crystal. In addition to standard measurements of the total light output and pulse shape at each angle, the prompt and delayed light anisotropies are analyzed, allowing for the investigation of the singlet and triplet molecular excitation behaviors independently. This paper provides new quantitative and qualitative observations that make progress toward understanding the physical mechanisms behind the scintillation anisotropy. These measurements show that the relationship between the prompt and delayed light anisotropies is correlated with a crystal structure, as it changes between the pi-stacked crystal structure materials (anthracene and p-terphenyl) and the herringbone crystal structure materials (stilbene, bibenzyl, and DPAC). The observations are consistent with a model in which there are preferred directions of kinetic processes for the molecular excitations. These processes and the impact of their directional dependences on the scintillation anisotropy are discussed. [ABSTRACT FROM AUTHOR]

We have evaluated radiation-induced charge trapping and low-frequency noise in passivated black phosphorus (BP) MOSFETs with HfO2 gate dielectrics. Thinning the gate dielectric reduces total ionizing dose-induced threshold voltage shifts. The defect-energy distribution estimated from low-frequency noise measurements performed as a function of temperature decreases with increasing energy in as-processed devices. Local maxima in noise magnitude are observed in irradiated devices at activation energies of ~0.2 and ~0.5 eV. Larger defect-related peaks in noise magnitude in the range of 0.35–0.5 eV are observed after biased post-irradiation annealing, and/or vacuum storage of the devices after irradiation and annealing. Density functional theory calculations strongly support significant roles for O vacancies in HfO2 and H+ transport and reactions near the BP/HfO2 interface in the observed radiation response and low-frequency noise. [ABSTRACT FROM AUTHOR]

Presents the table of contents for this issue of this publication. [ABSTRACT FROM PUBLISHER]

This paper presents a monitor circuit designed for the detection of extra combinational delays in a high-frequency SRAM-based field-programmable gate array (FPGA). Since in most of the SRAM-based FPGAs, more than 90% of the configuration bits control the routing resources, systems designed on FPGA are particularly vulnerable to interconnection delay changes (DCs) caused by single-event upset (SEU) affecting the configuration memory. The proposed monitor is part of a mitigation technique dedicated to protect the circuit routing delay integrity while the system is being exposed to SEUs generated by radiation. Experimental results show that the probability of DC occurrence can increase when the number of DCs affecting a node increases. Indeed, this increase depends on the configurable interconnection network and design placement in FPGA. Delay measurements using the proposed monitor revealed the existence of single DCs ranging from 29 to 151 ps. Also, cumulative DCs in the range of 279–309 ps being the results of an extra interconnection network added by SEUs have been detected. Measured delay values are in good agreement with those observed experimentally under proton radiation and also circuit-level simulations and emulations. [ABSTRACT FROM PUBLISHER]

Nanoscale field-programmable gate array (FPGA) circuits are more prone to radiation-induced effects in harsh environments because of their memory-based reconfigurable logic fabric. Consequently, for mission- or safety-critical applications, appropriate fault-tolerance techniques are widely employed. The most commonly applied technique for hardening FPGAs against radiation-induced upsets is triple modular redundancy (TMR). Voting circuits used in TMR implementations are decentralized and consensus is calculated from the redundant outputs off-chip. However, if there are an insufficient number of pins available on the chip carrier, the TMR system must be reduced to an on-chip unprotected simplex system, meaning voters used at those locations become single point of failure. In this paper, we propose a self-checking voting circuit for increased reliability consensus voting on FPGAs. Through fault injection and reliability analyses, we demonstrate that the proposed voter, which utilizes redundant voting copies, is approximately 26% more reliable than an unprotected simplex voter when reliability values of voters over normalized time are averaged. [ABSTRACT FROM PUBLISHER]

A radiation-tolerant digital multiphase current-mode hysteretic point-of-load regulator fabricated on a commercial 180-nm CMOS process is presented. Experiments and simulations are used to demonstrate its single-event immunity and its total-dose tolerance over 100 krad(Si). Key electrical performance parameters are: 5-V input, 0.8–3.3 V output, 10-A load current, 93% peak efficiency, four-phase hysteretic quasi-current-mode buck converter with ±1.5% frequency synchronization, ±3.6% current sharing error, and 1% ripple. [ABSTRACT FROM AUTHOR]

The radiation hardness of AlGaN/GaN high-electron-mobility transistors (HEMTs) is found to improve with increasing GaN channel thickness. Epitaxial MgCaO shows promise as a radiation-tolerant gate dielectric, with only small shifts in operating parameters of metal–oxide–semiconductor HEMTs observed at doses up to 1 Mrad(SiO2). Bias-induced electron trapping and radiation-induced-hole trapping can occur in the MgCaO, depending on the applied bias during stress and/or irradiation. AC transconductance measurements are used to help understand charge trapping in these devices. [ABSTRACT FROM PUBLISHER]

This paper describes a framework for incorporating linear radiation effects into the statistical machinery of the AE9/AP9 radiation climatology model software via “kernel” files. Users can provide their own kernels without modification of the software. Kernels can be applied to a variety of radiation effects such as proton single-event effect rate, internal charging current, ionizing dose, and nonionizing dose. Kernels can be generated for custom shielding geometry and materials and for custom parts or material susceptibilities. [ABSTRACT FROM PUBLISHER]

Total-ionizing-dose-induced resonance frequency shifts in piezoresistive micromachined cantilevers are experimentally shown to be dose-rate dependent. Devices were irradiated to 1 Mrad(SiO2) at rates from 5.4 to 30.3 krad(SiO2)/min, with lower rate exposures producing up to four-times more negative frequency shifts than higher rate exposures. Devices that were hydrogenated in a steam bath for 1 h showed shifts similar to those of control (not hydrogenated) devices at higher dose rates, and larger shifts than control devices at lower rates. All devices recovered to levels close to preirradiation after several hours of post-irradiation annealing. The dose-rate dependence is attributed to differences in carrier concentration caused by varying efficiencies of the depassivation of boron by hydrogen at higher and lower dose rates and/or surface charging effects, and the subsequent differences in Young’s modulus that occur as a result. Many of these processes are similar to effects that lead to ELDRS in linear bipolar transistors, emphasizing the need to include low-dose-rate testing of microelectromechanical systems devices when considering them for use in space systems. [ABSTRACT FROM PUBLISHER]

Compact environmental anomaly sensor risk reduction (CEASE-RR) is a new sensor designed for anomaly attribution due to the space radiation environment. It does this using two solid-state particle telescopes that have been designed to measure proton and electron fluxes that are the drivers for three of the four primary space environment effects (event total dose, deep-dielectric charging, and single event effects). These telescopes are integrated into a compact package along with space reserved for a planned electrostatic analyzer being developed for the final CEASE 3 design (covering the fourth primary space environment effect—surface charging). The sensors themselves will measure a wider dynamic range in particle flux, provide higher energy resolution, have better out-of-band contamination rejection, and improved diagnostic capability compared to previous CEASE instruments. The CEASE-RR instrument is planned to be launched in 2018 to geostationary orbit as part of an Air Force Research Laboratory flight experiment. The sensor design, calibration, and planned flight experiment objectives are described in this paper. [ABSTRACT FROM PUBLISHER]

Due to current technology scaling trends, digital designs are becoming strongly susceptible to space radiation effects. These effects can cause unwanted single-event upsets (SEUs) in any state element. This paper presents a new system-level model of SEUs propagation through processors as a continuous-time Markov chain (CTMC). Moreover, probabilistic formal techniques (such as probabilistic model checking) are utilized to exhaustively estimate the impact of SEUs on the system behavior. The proposed CTMC model was analyzed for different SEU injection scenarios and different bit-flip rates. Results demonstrate that the proposed approach can provide an accurate estimation of different reliability metrics, such as mean time to failure, mean time to recover, and the probability of failure for each SEU injection scenario in the system’s subcomponents. Furthermore, the proposed probabilistic system-level analysis was utilized to investigate the optimal self-repair rate required in the system to obtain the desired level of reliability. Results demonstrate that in comparison with existing simulation techniques for fault impact evaluation, the presented approach can provide consistent results while being orders of magnitude faster in terms of CPU time. [ABSTRACT FROM AUTHOR]

This paper studies perspectives on using optical fibers and distributed fiber sensing schemes to perform real-time-distributed gamma-ray radiation sensing with high spatial resolution. The radiation-induced optical property changes of aluminum-doped fibers were studied using cobalt-60 sources. The distributed optical loss of the aluminum-doped fiber was characterized using the Rayleigh backscattering optical frequency domain reflectometry (Rayleigh OFDR). The optical loss of unprotected fiber under various gamma dose rates remains linear up to 100 grays (Gy). Using the gamma radiation-sensitive fiber, the localized optical loss measured by the Rayleigh OFDR was used to map the accumulated gamma radiation dosage on the entire surface of the cylinder with a 1-cm spatial resolution. Using electrical cables as a ubiquitous sensor platforms for fiber sensor deployment, this paper explores the potential for multifunctional distributed fiber sensor by integrating distributed fiber temperature and gamma ionizing radiation sensors in electrical cables for multifunctional measurements to improve the safety of nuclear power systems at both the component and system levels. As sensors that can readily be embedded in a wide variety of materials and structures, radiation-sensitive fibers can be low-cost and highly flexible tool to gauge the performance degradation and longevity of materials and components used in the nuclear power systems. [ABSTRACT FROM AUTHOR]

The control area network (CAN) wired communication standard is becoming the bus of choice for many space applications. However, the severe −2 to 7 V common-mode and −3 to 16 V failure tolerance requirements of the CAN bus driver have restricted its implementation of commercial high-voltage processes with transistors tolerant to voltages above 16 V. These transistors experience sensitivity to single-event gate rupture (SEGR) and single-event breakdown (SEB) radiation events and have led to the limited diffusion of commercial available CAN transceivers in space applications. This paper demonstrates, for the first time, that a radiation-tolerant CAN driver can also be realized with the radiation-tolerant low-voltage design against radiation effects (DARE) mixed-mode 180-nm CMOS technology. This has been made possible by the development of a specific driver circuit that increases in static and dynamic operations of the technology voltage handling range from 3.3 to 16 V, while maintaining the radiation tolerance. This CAN driver has been manufactured and tested under heavy ion radiation in excess of linear energy transfer (LET) of 60 MeVcm2/mg. Over the CAN common mode and failure tolerance voltage range up to 16 V, this CAN driver has been tested and found to have a high threshold and low cross section to radiation-induced single-electron transients and an absence of single-event latch-up, SEGR, and SEB sensitivity. [ABSTRACT FROM PUBLISHER]

We present experimental evidence of electron-induced upsets in a reference European Space Agency (ESA) single event upset (SEU) monitor, induced by a 200-MeV electron beam at the Very energetic Electronic facility for Space Planetary Exploration in harsh Radiation environments facility at CERN. Comparison of experimental cross sections and simulated cross sections is shown and the differences are analyzed. Possible secondary contributions to the upset rate by neutrons, flash effects, and cumulative dose effects are discussed, showing that electronuclear reactions are the expected SEU mechanism. The ESA Jupiter Icy Moons Explorer mission, to be launched in 2022, presents a challenging radiation environment due to the intense high-energy electron flux in the trapped radiation belts. Insight is given to the possible contribution of electrons to the overall upset rates in the Jovian radiation environment. Relative contributions of both typical electron and proton spectra created when the environmental spectra are transported through a typical spacecraft shielding are shown and the different mission phases are discussed. [ABSTRACT FROM PUBLISHER]

Electrical behavior of commercial off-the-shelf normally-off GaN power transistors under heavy ion irradiation is presented based on technology computer aided design numerical simulation in order to better understand the mechanism of single event effects (SEEs) in these devices. First, the worst case has been defined from the single event transient mechanism. Then, the decrease in the electric field observed after irradiation and the traps effect have been addressed. Finally, possible mechanisms of SEE in these devices under heavy ion are proposed. [ABSTRACT FROM PUBLISHER]

The very high radiation fluences expected at the high-luminosity large hadron collider (LHC) impose new challenges in terms of design of radiation resistant silicon detectors. The choice to use p-type substrates to improve the charge collection efficiency involves an optimization of the strip isolation to interrupt the inversion layer between the n^+ implants, limiting the breakdown voltage. To this purpose, TCAD modeling and simulation schemes, already developed and validated at typical LHC fluences have to be adapted to take into account effects usually neglected at lower fluences. To better understand in a comprehensive framework, the complex and articulated phenomena related to bulk and surface radiation damage, measurements on test structures and sensors, as well as TCAD simulations related to bulk, surface and interface effects, have been carried out. In particular, we have studied the properties of the SiO2 layer and of the Si-SiO2 interface, using MOS capacitors and gate-controlled diodes (gated diodes) manufactured by different vendors on a high-resistivity p-type silicon before and after irradiation with X-rays in the range from 50 krad to 10 Mrad. In this paper, we present the results of the experimental characterizations as well as the simulation findings, in order to analyze the effects of the interface traps on the strip isolation. This analysis helps us to validate the model and to identify the most sensitive technological and design parameters to be optimized for the design of advanced 2-D and 3-D silicon radiation detectors. [ABSTRACT FROM PUBLISHER]

The propagation of single-event transient (SET) signals in a silicon–germanium direct-conversion receiver carrying modulated data is explored. A theoretical analysis of transient propagation, verified by simulation, is presented. A new methodology to characterize and quantify the impact of SETs in communication systems carrying modulated data is proposed. The proposed methodology uses a pulsed radiation source to induce distortions in the signal constellation. The error vector magnitude due to SETs can then be calculated to quantify errors. Two different modulation schemes were simulated: QPSK and 16-QAM. The distortions in the constellation diagram agree with the presented circuit theory. Furthermore, the proposed methodology was applied to evaluate the improvements in the SET response due to a known radiation-hardening-by-design (RHBD) technique, where the common-base device of the low-noise amplifier was operated in inverse mode. The proposed methodology can be a valid technique to determine the most sensitive parts of a system carrying modulated data. [ABSTRACT FROM PUBLISHER]

The impact of varying: 1) metals used to form contact electrodes and 2) chalcogenide glass atomic ratio/chemical composition on the performance of our recently developed flexible radiation detection sensors has been investigated. For electrodes, three group 11 elements (i.e., copper, silver, and gold) were used. For chalcogenide glass film, either GexS1−x or GexSe1−x was used where the atomic ratio of the chalcogen atoms (i.e., sulfide or selenide) was varied from device to device. Selenide systems with Ag electrodes were found to be very promising, since the limit of detection of the sensors showed clear dependence on the Se atomic ratio in the chalcogenide glass film. The other selenide and sulfide systems with different group 11 metal electrodes were not as suitable for the present lateral diffusion-based design due to either their control instability or very slow diffusion caused by $\gamma $ irradiation from a 60Co source. [ABSTRACT FROM PUBLISHER]

A recent model provides risk estimates for the deprogramming of initially programmed floating gates via prompt charge loss produced by an ionizing radiation environment. The environment can be a mixture of electrons, protons, and heavy ions. The model requires several input parameters. This paper extends the model to include TID effects in the control circuitry by including one additional parameter. Parameters intended to produce conservative risk estimates for the Samsung 8 Gb SLC NAND flash memory are given, subject to some qualifications. [ABSTRACT FROM PUBLISHER]

This paper revisits the stochastic computing paradigm as a way to implement architectures dedicated to probabilistic inference. In general, it is assumed the operation over stochastic bit streams is robust with respect to radiation transient events effects. Moreover, it can be expected that leveraging the stochastic computing paradigm to implement probabilistic computations such as Bayesian inference implemented in hardware could yield an increased resilience to radiation effects comparatively to deterministic procedures. However, the practical assessment of the robustness against radiation is mandatory before considering stochastic Bayesian machines (SBMs) in hazardous environments. Results of fault injection campaigns at register transfer level provide the first evidences of the intrinsic robustness of SBMs with respect to single event upsets and single event transients. [ABSTRACT FROM PUBLISHER]

We report an experimental investigation on the radiation-induced attenuation (RIA) in the ultraviolet-visible domain for Ge-doped optical fibers, during X-ray (10 keV) exposure at different temperatures. The objective is to characterize the impact of the irradiation temperature on the RIA levels and kinetics. Our data highlight that for dose exceeding 1 kGy(SiO2) the RIA spectrum changes with the irradiation temperature. In particular, for wavelengths below 470 nm the RIA depends both on the dose and on the irradiation temperature, whereas at higher wavelengths the RIA depends only on the dose. From the microscopic point of view the origin of this behavior is explained by a larger impact of the irradiation temperature on the Ge(1) defects generation mechanism with respect to the one of GeX defects, which appears as poorly temperature sensitive in the tested range. This finding prevents us from easily establishing a conclusive relation between the generation mechanisms of these two types of defects. The lower content of radiation induced Ge(1), in fiber irradiated at higher temperature, is supported by the electron paramagnetic resonance (EPR) results acquired after the irradiation. In situ RIA and postmortem EPR data show a significant correspondence of the Ge(1) growth as a function of the dose. Confocal microscopy luminescence experiments indicate that the non-bridging oxygen hole center concentration is higher at 473 K in comparison with those observed at 300 and 373 K. [ABSTRACT FROM PUBLISHER]

We evaluate the potential of the cathodoluminescence (CL) spectroscopy to characterize the nature and the spatial distribution of point defects in the main classes of optical fibers (OFs): Telecom-grade, radiation-hardened, and radiation sensitive. Canonical samples, that are differently doped in their cores (Ge, N, P, Ce) or their claddings (F), have been investigated through CL technique using a 10-keV electron beam. Obtained results are compared with those obtained by photoluminescence spectroscopy. CL benefits and limits are discussed on the basis of the obtained experimental data. CL is shown to be efficient to investigate the kinetics of defect generation and bleaching under the electron exposure, being the unique technique allowing us to determine in situ the spatial distribution of emitting defects in the fiber transverse cross sections. New insights are given for some of the defects related to the Ge, P, Ce and N dopants. [ABSTRACT FROM PUBLISHER]

The purpose of this paper is to present two new noise reduction filters techniques in the CT image space, in order to provide a better quality to the images acquired with low radiation exposure. For the noise reduction, a new denoising technique is presented based on a pointwise Maximum a Posteriori (MAP). The noise is considered Gaussian with zero mean, as observed experimentally, and the variance is estimated considering a signal-independent noise. For the a priori density of the signal, we used different non-negative probability densities (reflecting the fact that the pixels of an image are non-negative). In another approach, the histogram of the images were segmented into unimodal parts and each segment was filtered using the filter based on the MAP criterion with the a priori density that best fits it. After filtering, the evaluation of the method is performed using the following criteria: Peak Signal-to-Noise Ratio, Universal Image Quality Index and Structural Similarity Index. The 2D filtering results are compared with the results obtained by pointwise Wiener filter. Simulation and real CT images results show that the proposed techniques increase the image quality and improve the use of a low-dose CT protocol. [ABSTRACT FROM AUTHOR]

We explore how radiation-resistant broadband erbium-doped fibers (EDFs) can be achieved by using a carefully selected chemical composition, without specific coating or specific packaging. In this framework, we define a factor of merit, an appropriate and effective tool to design a radiation-hardened EDF amplifier (EDFA) based on a mature technology. We focus on specialty fibers, with a finely tuned composition in aluminum and erbium, guaranteeing the optimal operation of an EDFA (a 20-nm bandwidth and an optical output power level of at least 18 dBm) in the classical booster configuration throughout the entire geostationary mission. These performances are estimated thanks to a standard accelerated test, with a 300-Gy dose deposition at a dose rate of 0.4 Gy/h. We also confirmed, based on experiments and modeling, the importance of the radiation-induced absorption at pump wavelength on the EDFA degradation under irradiation. [ABSTRACT FROM AUTHOR]

The transition metal oxide NbO2 is regarded as a promising selector device to be integrated with resistive random access memory for the high-density crossbar array architecture. Understanding its total ionizing dose (TID) response would help assess the reliability of using this selector device in radiation environments. In this paper, we investigate the TID effect of gamma-ray ( $\gamma$ -ray) radiation on a Pt/NbOx/Pt selector device using electrical characterization and an X-ray photoelectron spectroscopy (XPS). The NbOx devices were irradiated with 60Co $\gamma$ -rays to a maximum dose of 5 Mrad (NbO2). The experimental results show that the threshold switching behavior can withstand the 5 Mrad (NbO2) without significant change in the switching parameters. The XPS results reveal that there are mixed NbO2 and Nb2O5 phases in the NbOx thin film. After 5 Mrad (NbO2) $\gamma$ -ray irradiation, the peak intensity of NbO2 increases and the peak intensity of Nb2O5 decreases in the XPS spectra, probably due to the reduction of Nb2O5 under radiation. Nevertheless, the electrical properties of the NbOx-based selector have remained after 5 Mrad (NbO2) $\gamma$ -ray irradiation, indicating the potential use of the NbOx-based selector device in aerospace applications. [ABSTRACT FROM AUTHOR]

We have investigated the ionization damage by 60Co gamma irradiation in 0.13- and 0.25- \mu \textm SiGe heterojunction bipolar transistors (HBTs). Both technologies feature high-speed HBTs (HS-HBTs) together with high-voltage HBTs (HV-HBTs). Base current degradation with increasing total irradiation dose is studied. An identical behavior of corresponding HS-HBT and HV-HBT is found for operation in forward mode probing the emitter–base junction. In reverse mode where the collector base junction is determining the base current degradation, HV devices exhibit larger degradation than their HS counterparts. The increased width of the collector–base space charge region in HV devices leads to enhanced interface recombination at the adjacent Si/oxide interfaces and stronger base current degradation. TCAD simulations of device degradation suggest a linear relationship between total irradiation dose and radiation-induced interface state density N\mathrm{ it} . [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM PUBLISHER]

Radiation particles are incident on an integrated circuit (IC) from all angles. For planar technologies, angular incidence increases the deposited charge in a given volume, resulting in higher collected charge at a node and more transistors collecting charge due to increased charge sharing. For FinFET technologies, the physical structure of a FinFET is very different from that of a planar transistor. As a result, deposited and collected charge at a node for angular incidences will be different from what has been published for planar technologies. 3D TCAD simulations and heavy-ion experiments were carried out to investigate the angular effects on flip-flop (FF) single-event upsets (SEU) at the 16-nm bulk FinFET technology. Results show different SEU cross-section trends for the FinFET technology compared to planar technologies. Results show increased upset probability and SEU cross-sections with increasing tilt angles, but those are reduced with increasing roll angles for low-LET heavy-ion incidence. The main reason for this behavior is posited to be variations in charge track length within active Si regions. [ABSTRACT FROM PUBLISHER]

Heavy-ion-induced single-event measurements for p-channel InGaSb quantum-well metal-on-insulator field-effect transistors (QW-MOSFETs) are demonstrated for a range of gate bias conditions. Two p-channel In0.33Ga0.67Sb QW structures were evaluated– a buried channel structure and a surface channel structure with and without an Al0.8In0.2Sb barrier layer respectively. The heavy-ion induced transient response is investigated for both structures. A slowly relaxing transient decay is observed in the buried channel device which is responsible for the bulk of the charge enhancement. It is effectively eliminated with the removal of the Al0.8In0.2Sb barrier, leading to a $10\times $ reduction in collected charge in the surface channel device. To analyze the transient response, a calibrated TCAD device simulation equipped with a heavy ion induced ionization model has been developed, which shows excellent agreement with the measured results for the entire range of evaluated gate bias conditions. The simulation analysis reveals that the charge collection enhancement phenomenon in a p-channel InGaSb QW-MOSFET is associated with the increased bipolar gain due to electron trapping in the Al0.8In0.2Sb barrier. [ABSTRACT FROM PUBLISHER]

This paper describes a FPGA configuration scrubbing approach for Xilinx 7-Series FPGAs that combines the high-speed internal scrubbing available within these devices with an external scrubber. The internal scrubbing unit continuously monitors the frames of the FPGA configuration memory and corrects single-bit frame errors and is used to detect multi-bit frame errors. Multi-bit upsets are repaired by means of a secondary scrubbing mechanism that is primarily external to the FPGA fabric. This Xilinx 7-Series hybrid configuration scrubbing architecture scans 25,636,224 bits of the XC7Z020 device in several microseconds and detects upsets within 8 ms and then corrects most multi-cell upsets in under an additional 6 ms. This configuration scrubber was validated with configuration fault injection and neutron radiation testing. [ABSTRACT FROM PUBLISHER]

The impact of semiconductor process scaling on the overall transient response of SiGe BiCMOS platforms is investigated. Pulsed-laser two-photon absorption (TPA) and heavy-ion broad-beam testing of SiGe HBT device and digital test structures across several generations of SiGe technologies are utilized to investigate the potential impacts of semiconductor process scaling (e.g., lateral/vertical scaling, changes in doping, Ge content, etc.) on the overall transient shape, magnitude, and duration. Technology scaling is shown to increase the single-event effect (SEE) sensitivity of SiGe HBTs (i.e., elevated collected charge, where 1st Gen. QC <3 rd Gen. QC <4 th Gen. QC ). Modern third-generation and fourth-generation devices under a forward-active bias (i.e., forward-biased EB junction, reverse-biased CB junction) exhibit a large diffusive transient component between the emitter and collector terminals, driving an elevation in collected charge. 3-D TCAD modeling is utilized to understand the fundamental transient mechanisms and assess the primary scaling factors affecting SEE sensitivity. Ion-strike simulations show that bulk traps can substantially enhance the charge collection mechanisms within these devices. These results suggest that SiGe technology scaling may have a strong impact on the radiation-induced transient response of SiGe HBTs, with future SiGe technology generations potentially exhibiting increased sensitivities to single-event effects. [ABSTRACT FROM PUBLISHER]

Fiber Bragg Grating (FBG) based sensors are nowadays used for several applications, but, even if they present advantages for their incorporation into radiation environments, commercial-off-the-shelf devices cannot still be used in harsh conditions. We recently reported a procedure for fabricating FBGs resistant to severe constraints combining both high radiation doses up to MGy levels and operation temperatures exceeding 200°C (RadHard FBGs). Following these results, the European project HOBAN was granted by Kic InnoEnergy with the aim of developing and marketing FBG-based temperature and strain monitoring systems suitable for harsh nuclear environments (350°C temperature and MGy dose levels), with their associated instrumentation devices. In this framework, we present an accurate study about the robustness of the radiation-response of these RadHard FBGs against the main grating inscription parameters. Up to the accumulated X-ray dose of 1 MGy(SiO2), no significant radiation induced Bragg wavelength shift is observed meaning that radiations induce errors below ± 0.4°C in the temperature estimation. Moreover, a study about the dose-rate dependence (1 to 50 Gy/s) of the gratings response is also reported and confirms the high radiation hardness of our RadHard FBGs at all dose rates. [ABSTRACT FROM PUBLISHER]

We report the study of a radiation resistant single mode optical fiber doped with fluorine exposed to mixed neutron and \gamma -radiation up to 10^{17} n/cm2 fluence and >2 MGy dose to evaluate its performances when used as the sensing element of a distributed Optical Frequency Domain Reflectometry (OFDR). The use of complementary spectroscopic techniques highlights some differences between the responses of solely \gamma -radiation (10 MGy) or mixed neutron and \gamma ( 10^{17} n/cm ^{2}+>2 MGy) irradiated samples. Those differences are linked to the defect generation rather than to structural changes of the a -SiO2 host matrix. We show that a modification of the refractive index of \sim 10^\mathrm -5 is induced at the highest investigated neutron fluence. However, the feasibility of distributed temperature measurements along the irradiated fiber is demonstrated with an accuracy of 0.1 °C over a sensing length up to ~ 130 m with the tested OBR4600 interrogator. These results are very promising for the integration of OFDR sensors in mixed neutron and gamma radiation environments. [ABSTRACT FROM PUBLISHER]

A guard-gate based flip-flop circuit temporally hardened against single-event effects is presented in this paper. Compared to several existed techniques, the organization of components inside the proposed design allows the improved performance– only one $\tau $ (the maximum width of a single-event transient (SET) to tolerate) is added into the setup time. A previously reported low-power delay element is applied, which helps make the proposed design power-efficient. The proposed design was implemented in a 65 nm CMOS bulk technology. Alpha and heavy-ions radiation experiments were performed to characterize its soft-error rates. Experimental results show that the proposed design presents no error with LETs up to 37.3 MeV-cm2/mg. Simulation results from the TFIT further validate the experimental results. [ABSTRACT FROM AUTHOR]