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Measurements of particle fluxes (protons and electrons) obtained with the Influence sur les Composants Avancées des Radiations de l’Espace for New Generation (ICARE_NG) monitor on the Eutelsat 7C orbit [Electric Orbit Raising to Geostationary Orbit (GEO)] are presented. Several comparisons are proposed with other instruments [magnetic electron ion spectrometer (MagEIS), relativistic proton spectrometer (RPS), and magnetospheric particle sensors high (MPSH)] and radiation models (AEP8, International Radiation Environment Near Earth (IRENE), and Global Radiation Earth ENvironment (GREEN)). Significant discrepancies have been found, especially with AEP8 model. The measurements when the satellite is in its operational orbit (GEO) have also been compared with the International Geostationary Electron (IGE) model and an excellent agreement is observed. For calculating fluxes from ICARE_NG outputs, two methods have been developed and their results are compared to consolidate our interpretations. [ABSTRACT FROM AUTHOR]

In recent years, a number of new scintillator materials with improved energy resolution for gamma-ray detectors have become commercially available for use in terrestrial-based homeland security applications, and some are being incorporated into instrumentation for space. Unlike terrestrial applications, the harsh environment of space—in particular, energetic trapped particles, cosmic rays, and neutrons—often activates these materials, and any improvement in sensitivity as a result of improved energy resolution could be offset by the additional background due to activation. The purpose of this work was to measure potential backgrounds due to trapped and cosmic-ray proton-induced activation in the new materials: SrI2:Eu (SrI), 7Li-enriched Cs2LiYCl6:Ce (CLYC-7), Cs2LiLaBr6:Ce (CLLB), Cs2LiLa(Br,Cl)6:Ce (CLLBC), Tl2LiYCl6:Ce (TLYC), and Gd3(Al,Ga)5O12:Ce (GAGG). Using a large-diameter 64-MeV proton beam, detectors were irradiated with a total dose of 100 rad (Si), roughly equivalent to the annual dose in a typical low earth orbit. Measurements were made with a single 100% relative efficiency high-purity germanium (HPGe) (0.05–3 MeV) and the irradiated detector. Two multichannel analyzers (MCAs) operating in the event mode were used to collect the data. Time-tagged events were processed into various spectral integration times for analysis, and characteristic gamma-ray energies and decay times were used to identify activation products. Most of the identified activation products were the result of (p, xn) reactions, with a few exceptions. This work identifies the primary radioisotopes generated by energetic proton activation in six different scintillator materials. [ABSTRACT FROM AUTHOR]

We prove that a nonequilibrium inhomogeneous giant gas discharge is realized in the heliosphere with huge values of the parameter $E/N$ , which determines the temperature of electrons. This quasi-stationary discharge determines the main parameters of the weak solar wind (SW) in the heliosphere. In connection with the development of space technologies and the human spacewalk, the problem of the nature of the SW is acute. The study of the interference of gravitational and electrical potentials at the earth’s surface began with the work of William Gilbert 1600. Such polarization effects–the interference of Coulomb and gravitational forces–have not been studied well enough even in the heliosphere. Our article is devoted to this problem. The Pannekoek–Rosselan–Eddington model does not consider the important role of highly energetic running (away from the Sun) electrons and, accordingly, the duality of electron fluxes in the heliosphere (from the Sun and to the Sun) According to an alternative model formulated by us, highly energetic (escaping from the positively charged Sun) electrons leave the Sun and the heliosphere, and weakly energetic ones, unable to leave the Coulomb potential well (hole–the positively charged Sun and the heliosphere–return to the positively charged Sun. The weak difference between the opposite currents of highly energetic (escaping from the Sun) electrons and weakly energetic (returning to the Sun) electrons is compensated by the current of positive ions and protons from the Su–SW. These dynamic processes maintain a quasi-constant effective dynamic charge of the Sun and the entire heliosphere all the way to the earth’s orbit. At the same time, quasi-neutrality (see discussion in the following) in the Sun and heliosphere is well performed up to 10−36. According to experiments and analytical calculations based on our model: 1) the plasma in the corona is nonequilibrium; 2) the maximum electron temperature is $T_{e}$ 1–2 million degree; 3) $T_{e}$ grows from 1000 km away from the Sun (see discussion in the following); and 4) the role of highly energetic electrons escaping from the plasma leads to a significant increase in the effective: solar charge and electric fields in the heliosphere in relation to the Pannekoek–Rosselan–Eddington model. This is due to the absence of a compensation layer that screens the effective charge of the Sun It is not formed due to the escape of highly energetic electrons (as in a conventional gas discharge) from the entire heliosphere with high temperatures exceeding the temperature of the Sun’s surface. Thus, the process of escape of highly energetic electrons forms the internal EMF of the entire heliosphere. Interference of gravitational and Coulomb potentials in the entire heliosphere is considered, and it is being manifested in generation of two opposite flows of particles: 1) that are neutral or with a small charge (to the Sun) and 2) in the form of high-energy electrons (escaping from the positively charged Sun) and an SW with positively charged ions with Z/M $\ge0.107$ (from the positively charged Sun). The calculated values of the registered ion parameters in the SW were compared with experimental observations. Reasons for generating the ring current in inhomogeneous heliosphere and inapplicability of the Debye theory in describing processes in the SW (plasma with current) are considered. [ABSTRACT FROM AUTHOR]

Nowadays, high-performance microprocessors are demanded in many fields, including those with high-reliability requirements. Commercial microprocessors present a good tradeoff between cost, size, and performance, albeit they must be adapted to satisfy the reliability requirements when they are used in harsh environments. This work presents a high-end multiprocessor hardened with macrosynchronized lockstep and additional protections. A commercial dual-core Advanced RISC Machine (ARM) cortex A9 has been used as a case study and a complete hardened system has been developed. Evaluation of the proposed hardened system has been accomplished with exhaustive fault injection campaigns and proton irradiation. The hardening approach has been accomplished for both baremetal applications and operating system (OS)-based. The hardened system has demonstrated high reliability in all performed experiments with error coverage up to 99.3% in the irradiation experiments. Experimental irradiation results demonstrate a cross-sectional reduction of two orders of magnitude. [ABSTRACT FROM AUTHOR]

The contribution of Coulomb processes induced by incident electrons in single event upset (SEU) sensitivity is investigated. The case of 65-nm silicon on insulator (SOI) memory is studied. Several orbits (GPS, Jupiter Icy Moons Explorer’s (JUICE’s) orbits) are analyzed. The relative importance to the total SEU rate of electron, proton, and gamma environments is compared. SEU induced by electrons is obtained during Earth missions. In the environment of Jupiter, equivalent SEU sensitivities have been obtained between the studied device and the European Space Agency (ESA) SEU monitor. However, the relative importance of the physical processes involved is very different. Proton-induced SEU rates are estimated about one decade greater than electron-induced SEU rates. The Bremsstrahlung contribution has been found negligible in such an environment. [ABSTRACT FROM AUTHOR]

The contribution of low-energy particles down to ~200 eV to the dose deposited on the very near surface of materials subject to the space environment is investigated by means of GEANT4 Monte Carlo simulations. The contribution to the dose, of the low-energy parts of Global Radiation Earth ENvironment (GREEN) spectra (200 eV–40 keV for electrons, 200 eV–100 keV for protons), is compared with calculations performed with AE8/AP8. Both geostationary earth orbit (GEO) and low earth orbit (LEO) SPOT like orbits are studied. The dose depth profiles are estimated for silicon material. The impact on the dose calculation of different transport models is also investigated. Below 1 keV, the relevance of continuous processes is analyzed for electrons by comparison with a discrete model [GEANT4/microelectronic (MICROELEC)]. This analysis is also performed for protons below 10 keV. [ABSTRACT FROM AUTHOR]

Single-event upsets are observed in a 72-layer 3-D NAND flash memory operated in a single-level cell mode after low-energy proton (500 keV–1.2 MeV) and heavy-ion irradiation. The layer-by-layer error count is analyzed to visualize the stopping of low-energy protons within the memory stack, and Monte Carlo simulations are correlated with the experimental data. Direct ionization by low-energy protons is identified by 3-D data analysis and the energy dependence of device-sensitive cross section. Heavy-ion data is also presented for comparison. [ABSTRACT FROM AUTHOR]

This work investigates the role of the phosphorus doping element in the radiation-induced dark current in a CMOS image sensor (CIS) photodiode. The neutron and proton irradiations on shallow arsenic-based photodiode CISs and deep phosphorus-based photodiodes CISs have been performed. The results highlight the applicability of the same dark current increase and random telegraph signal (RTS) models. Already verified on other photodiode structures, these results further extend the universality of these analytic tools. Moreover, it emphasizes that the phosphorus element does not play a significant role either in the radiation-induced dark current increase or in the dark current RTS. The results on RTS after annealing reveal the same recovery dynamic than those already observed in irradiated image sensors, suggesting that the phosphorus element does not play a significant role after annealing. Therefore, this work is a piece of experimental evidence supporting the idea that RTS induced by displacement damage is principally due to defect clusters mainly constituted of intrinsic silicon defects such as clusters of vacancies and interstitials. [ABSTRACT FROM AUTHOR]

The effects of the white-light X-ray and 170-keV proton beam irradiation on the electrical and optical characteristics of the InGaN/GaN multiple quantum wells (MQWs) light-emitting diodes (LEDs) are analyzed and compared. Different from the negative effects of the proton irradiation, the X-ray irradiation shows positive effects on the LEDs’ performance. In detail, after the 100 Mrad(Si) X-ray irradiation, the p-n junction resistance decreases from the original 2.51 to 2.08~Ω, the light output power increases from 170 to 203 mW (at a forward voltage of 3.2 V), and the maximal external quantum efficiency (EQE) increases from 56.7% to 61.8%. Based on the ABC model fittings, both the Shockley–Read–Hall recombination rate and the radiative recombination rate in the MQWs are improved by the X-ray irradiation. The Hall effect measurements reveal the chemical bond breaking of the Mg-H complex in the p-type GaN. Therefore, the improvement of the LED by the X-ray irradiation should be caused by the chemical bond variations of the defect-related complex in the MQWs and the Mg-H complex in the p-type GaN. [ABSTRACT FROM AUTHOR]

CNES and ONERA have developed a radiation monitor Influence sur les Composants Avancés des Radiations de l’Espace-Nouvelle Génération (ICARE-NG) to measure the protons and electrons in radiation belts. This instrument is able to measure a wide range of energy for protons and electrons, but no measurements of few MeV protons are performed. The objective of this article is to extend the capabilities of this radiation monitor by adding a low-energy proton sensor. In this article, the design of a sensor for low-energy protons compatible with the ICARE-NG instrument is presented. Response functions for protons and electrons of the low-energy proton sensor are calculated using Monte Carlo simulations. The calculation of predicted count rates of particles is performed. The manufacturing of the instrument as well as tests is discussed. [ABSTRACT FROM AUTHOR]

Ion bombardment of electrodes in an electric vacuum device can induce high-voltage breakdown. In order to explain this phenomenon, we, for the first time, analyzed a typical model of protons impacting the electrode with the help of a particle-in-cell (PIC)-direct simulation Monte Carlo (DSMC) code. In this model, we considered both the secondary electron yield and the gas desorption from the electrode. The temporal and spatial distribution evolution of electrons, ions, and neutrals under different electrode conditions is presented. The critical value of local gas density to induce breakdown is 1025 m−3. According to the discussion of the formation of the electrons avalanche, the electron ionizing gas is the key component for affecting the formation of a breakdown, and the production of plasma sheath near the electrode greatly contributes to the electrons avalanche. [ABSTRACT FROM AUTHOR]

The Influence sur les Composants Avancés des Radiations de l’Espace-Nouvelle Génération (ICARE-NG) instrument onboard the Argentinian satellite Satelite de Aplicaciones Cientificas-D (SAC-D) detected much more protons during descending orbits (when latitude decreases) than for ascending orbits (increasing latitudes). In this paper, we will investigate the anisotropy seen by ICARE-NG Head-A for protons in the coincidence mode from Monte Carlo simulations performed with GEANT4. Our simulations show that the difference in the fluxes observed during ascending and descending orbits comes from the fact that the instrument observed trapped protons or not on each point of the orbits as a result of the instrument and satellite orientations. In addition, we show in this paper that the measurements performed by ICARE-NG can be used in conjunction with our GEANT4 simulations to study the anisotropy of trapped protons, i.e., their distribution relative to their equatorial pitch angle. [ABSTRACT FROM AUTHOR]

We present heavy ion and proton data on AlGaN high-voltage HEMTs showing single event burnout (SEB), total ionizing dose, and displacement damage responses. These are the first such data for materials of this type. Two different designs of the epitaxial structure were tested for SEB. The default layout design showed burnout voltages that decreased rapidly with increasing LET, falling to about 25% of nominal breakdown voltage for ions with LET of about 34 MeV $\cdot $ cm2/mg for both structures. Samples of the device structure with lower AlN content were tested with varying gate–drain spacing and revealed an improved robustness to heavy ions, resulting in burnout voltages that did not decrease up to at least 33.9 MeV $\cdot $ cm2/mg. Failure analysis showed that there was consistently a point, location random, where gate and drain had been shorted. Oscilloscope traces of terminal voltages and currents during burnout events lend support to the hypothesis that burnout events begin with a heavy ion strike in the vulnerable region between gate and drain. This subsequently initiates a cascade of events resulting in damage that is largely manifested elsewhere in the device. This hypothesis also suggests a path for greatly improving the susceptibility to SEB as development of this technology goes forward. Testing with 2.5-MeV protons showed only minor changes in device characteristics. [ABSTRACT FROM AUTHOR]

The usage of static random access memory-based field programmable gate arrays (FPGAs) on high-energy physics detectors is mostly limited by the sensitivity of devices to radiation-induced upsets in their configuration. In this paper, we describe a scrubber core designed for Xilinx FPGAs, based on configuration redundancy. When no upsets happen in homologous redundant bits and the scrubber is functional, the adopted redundancy makes it possible to correct all the errors. In fact, the scrubber corrects its own configuration and the one pertaining to a given user design. We discuss the architecture and two implementations of the scrubber, corresponding to different flavors of triple modular redundancy. We report results from proton irradiation tests, which prove that our core can extend the lifetime of a benchmark circuit up to 290%. [ABSTRACT FROM AUTHOR]

The charge deposition of particles in materials is the primary stage in inducing ionization radiation effects. We analyzed charge depositions of heavy ion, proton, and neutron in digital integrated circuit (IC) materials [i.e., C(diamond), Si, Ge, and GaAs] and power IC materials [i.e., C(diamond), Si, SiC, and GaN] in this paper. For proton and heavy ion direct ionizations, the maximum deposited charge per unit length [i.e., (dQ/dx)max] was extracted for comparisons among these materials. For proton and neutron indirect ionizations, the maximum recoil-deposited charge (i.e., Qdepmax) and the recoil numbers were used for comparisons. The deposited charge by the low-energy recoils was modeled by the ionization efficiencies which were obtained from transport of ions in matter Monte Carlo simulations. The influences of temperature and doping concentration were also discussed. [ABSTRACT FROM AUTHOR]

Total ionizing dose effects are investigated on a physically unclonable function (PUF) based on CMOS breakdown. Devices irradiated to 2 Mrad(SiO2) show less than 11% change in current ratio at 1.2 V. The read-out window of programmed PUFs decreases significantly at high-dose proton irradiation, and then recovers back to the original value after annealing. The proton test results for the pFET selector, the unbroken nFET, and the broken nFET indicate that the threshold-voltage shift of the pFET selector contributes mainly to the degradation of the PUF. [ABSTRACT FROM AUTHOR]

In this letter, ferroelectric memory performance of TiN/Y-doped-HfO2 (HYO)/TiN capacitors is investigated under proton radiation with 3-MeV energy and different fluence (5e13, 1e14, 5e14, and 1e15 ions/cm2). X-ray diffraction patterns confirm that the orthorhombic phase Pbc21 of HYOfilm has no obvious change after proton radiation. Electrical characterization results demonstrate slight variations of the permittivity and ferroelectric hysteresis loop after proton radiation. The remanent polarization (2Pr) of the capacitor decreases with increasing proton fluence. But the decreasing trend of 2Pr is suppressed under high electric fields. Furthermore, the 2Pr degradation with cycling is abated by proton radiation. These results show that the HYO-based ferroelectric memory is highly resistive to proton radiation, which is potentially useful for space applications. [ABSTRACT FROM PUBLISHER]

A characterization study was carried out to determine if a novel, millimeter sized Terbium-activated Gadolinium Oxysulfide optical fibre detector has potential for future use in proton dosimetry. Preliminary studies employed a Theratronics Theratron 780C Cobalt-60 unit and were used to determine nominal dose response, field size response and Čerenkov contributions in 1.25-MeV gamma radiation. More extensive testing was done using 74 MeV-protons produced in the TRIUMF 500-MeV cyclotron facility examining raw Bragg peak, spread out Bragg peak, dose response, and Čerenkov signal. The detector was low-cost and easily assembled; it showed excellent sensitivity, signal to noise ratio, and reproducibility. Quenching at high linear energy transfer was severe. Additional investigations are needed to further explore Čerenkov-only depth-dose curves, signal detection at the extreme distal end of the Bragg peak, and possible sensitivity to neutrons. [ABSTRACT FROM PUBLISHER]

This paper reports the results of electron irradiations at various energies of the Samsung 8-Gb single-level cell nand flash memory. The percentage of bit errors from electron exposure is compared to results from 60Co total ionizing dose (TID) measurements. Electron irradiation at low energies (below 2 MeV) causes more bit upsets than 60Co gamma exposures at the same TID level when TID refers to equilibrium dose (as opposed to local dose). Bit upsets increase when electron energy decreases if comparisons are made at the same equilibrium dose level. In particular, 60-MeV electrons are less damaging than 60Co gamma exposures at the same equilibrium dose level while 1-MeV electrons are more damaging. However, all radiation sources produce virtually identical results when comparisons are made at the same local dose level, indicating that charged-particle equilibrium is violated during electron irradiations. [ABSTRACT FROM PUBLISHER]

Static RAM-based field programmable gate arrays (SRAM-based FPGAs) are widely adopted in trigger and data acquisition systems of high-energy physics detectors for implementing fast logic due to their reconfigurability, large real-time processing capabilities and embedded high-speed serial IOs. These devices are sensitive to radiation-induced upsets, which may alter the functionality of the implemented circuit. Presently, their usage on-detector is limited and there is a strong interest in finding solutions for improving their tolerance to radiation-induced upsets. In this paper, we show a novel configuration-redundancy generation and scrubbing technique for SRAM-based FPGAs. It leads to a power saving with respect to other solutions in the literature. Moreover, our technique is compatible with several Xilinx FPGA families. Our solution does not require neither the usage of external memories nor third-party layout tools. We describe an example of our solution applied to a benchmark design implemented in a Xilinx Kintex-7 FPGA. In order to prove the effectiveness of the solution, we present results from a proton irradiation test. [ABSTRACT FROM AUTHOR]

Proton irradiation at 5 MeV was performed on normally-off p-AlGaN gate AlGaN/GaN high electron mobility transistors (HEMTs). The increase of on-resistance and the degradation of subthreshold characteristics were observed after irradiation. The reduction of on-current was induced by displacement damage which also affected ungated devices with no p-AlGaN gate layer. Thermal annealing partially recovered this reduction. The subthreshold degradation with the threshold voltage ( \text V\mathrm {th} ) shift was proportional to the irradiation dose. TCAD simulation indicated that the decrease of hole concentration in p-AlGaN layer resulted in the negative shift of \text V\mathrm {th} and the subthreshold degradation. [ABSTRACT FROM PUBLISHER]

Retention time and cell functionality degradation under proton irradiation is studied for SDRAM references that exhibit in-flight faulty behavior on satellites. Proton irradiation, with an adapted test protocol, allows to reproduce these effects and to gain a valuable insight on this phenomenon. Data acquired allow for a physical interpretation of the degradation, which results of one or more damage clusters created by a single particle. [ABSTRACT FROM PUBLISHER]

The development of a proton radiography system to improve the imaging of patients in proton beam therapy is described. The system comprises gridpix based time projection chambers, which are based on the Timepix chip designed by the Medipix collaboration, for tracking the protons. This type of detector was chosen to have minimal impact on the actual determination of the proton tracks by the tracking detectors. To determine the residual energy of the protons, a BaF 2 crystal with a photomultiplier tube is used. We present data taken in a feasibility experiment with phantoms that represent tissue equivalent materials found in the human body. The obtained experimental results show a good agreement with the performed simulations. [ABSTRACT FROM AUTHOR]

This paper presents a single event burnout (SEB) sensitivity characterization for power MOSFETs, independent from tests, through a prediction model issued from TCAD analysis and the knowledge of device topology. The methodology is applied to a STRIPFET device and compared to proton data obtained at PSI, showing a good agreement in the order of magnitude of proton SEB cross section, and thus validating the prediction model as an alternative device characterization with respect to SEB. [ABSTRACT FROM PUBLISHER]

This paper investigates the impact of the radial ionization profile of proton on SEU sensitivity for nanoscale devices. Intrinsic radial track structures of energy deposition of protons (from 0.5 to 2 MeV) in a silicon box with 2~\mu\m of Si over-layer and a 100-nm silicon film were investigated. The orders of magnitude of the radial deposition is around 200 to 300 nm. Approaches based on punctual or average depositions induce a drift increasing for nanoscale volumes. Realistic energy deposition databases were developed thanks to GEANT4 and coupled with MUSCA SEP3 to perform SEU cross sections and SER estimations. Calculations applied to SOI and bulk technologies (65 and 45-nm) were conducted and compared with experimental results. Calculations are consistent with experiments, despite some drifts. Analyses demonstrate the necessity to consider the 3D morphology description in SEE modeling for nanoscale technologies, more particularly for SOI technologies. [ABSTRACT FROM PUBLISHER]

The effects of proton-induced displacement damage in GaN HEMTs on circuit-level RF power amplifier parameters such as circuit gain, stability, and RF output power are presented. The results are explained based on the device-level degradation. Commercial-off-the-shelf GaN HEMTs from two manufacturers were compared. Differences are observed in both device and circuit level responses. Suggestions to mitigate the negative effects of displacement damage on GaN based amplifiers are also provided. [ABSTRACT FROM PUBLISHER]

Proton experimental data are analyzed for a 16-Mbit thin-film-transistor (TFT) PMOS static random access memory (SRAM) with DRAM capacitors. The presence of high-Z materials as tungsten causes an unusual increase of the single event upset (SEU) proton cross section for the energies above 100 MeV. Monte-Carlo simulations reproduce the experimentally measured cross sections up to 480 MeV and predict a further increase up to GeV energies. The implications of this increase are analyzed in the context of the LHC and other radiation environments where a significant fraction of the fluence lies above 100 MeV. [ABSTRACT FROM PUBLISHER]

AlGaN/GaN high electron mobility transistors (HEMTs) irradiated with 1.8-MeV protons show more relative degradation in RF power/current gain, cutoff frequency f_T, and maximum oscillation frequency fmax than DC transconductance. These result from radiation-induced increases in fast bulk and surface trap densities, as well as increasing impedance mismatch at high frequencies with increasing proton fluence. NH3-rich MBE devices show less degradation in DC transconductance, but more degradation in RF gain than Ga-rich devices. [ABSTRACT FROM PUBLISHER]