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The first two units of the ESA Next Generation Radiation Monitor (NGRM) sensor are flying onboard the European Data Relay System, Satellite-C (EDRS-C), and the Sentinel-6 Michael Freilich (S-6), providing critical information related to the space radiation environment. This work presents a first evaluation and analysis of the measurements of the unit hosted on EDRS-C during the geostationary transfer orbit (GTO) of the satellite. The evaluation studies include comprehensive comparisons with measurements from other radiation monitors and science-class experiments. NGRM datasets will become publicly available in real time from the space weather (SWE) data center through dedicated applications contributing to the monitoring of SWE and the characterization of the space radiation environment. [ABSTRACT FROM AUTHOR]

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]

The Earth’s electron radiation environment is extremely dynamic. It reacts strongly to magnetic storms, increasing in some hours by several orders of magnitude in a large energy range and decreasing slowly in the recovery phase of the storm. For the purpose of spacecraft Electrical Orbit Raising (EOR), to bring the ion thruster propulsion-based satellites from the launcher injection orbit to the geostationary orbit, it is important to estimate the electron fluxes they can encounter during this long transfer phase. Using correlation between high-energy electron measurements at LEO and near equator, a methodology is presented and validated to infer the daily average flux encountered by the EUTELSAT 7C spacecraft during its EOR phase. [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]

This article presents a fast-transient radiation-hardened low-dropout (LDO) voltage regulator integrated in a standard 0.6- $\mu \text {m}$ BiCMOS technology for space and other harsh radiation environment applications. The fabricated LDO consumes 150- $\mu \text {A}$ quiescent current at 6-A maximum output current. An LDO voltage of 300 mV which corresponds to an ultralow $R_{\text {DS}(\text {ON})}$ resistance of 50 $\text{m}\Omega $ is realized by accurate modeling. A separate fast-transient response circuit under narrow-bandwidth condition is proposed to improve the output voltage transient speed. It operates from an input voltage range of 2.8–5.5 V and provides an output voltage of 2.5 V, with output voltage accuracy of ±2%. The proposed LDO achieves a successful line regulation of 1 mV/V, and a load regulation of 2.16 mV/A. Effective radiation-hardened layout techniques are applied to realize high area-efficient LDO chip, whose total area including pads is 5.35 mm2, which represents only about one-third area of similar radiation-hardened products. Furthermore, a special set of total ionizing dose (TID) experiments and single-event latch-up (SEL) experiments were performed. The measurement results show that the LDO can tolerate up to a TID of 150 krad (Si) and SEL immunity at a linear energy transfer (LET) of 99.8 MeV/(mg/cm2) with proposed layout design. [ABSTRACT FROM AUTHOR]

This article reports on the calculation of upset rates in low and medium earth orbits using a design-of-experiments and Monte-Carlo approach to the parameters available in the Cosmic-Ray Effects on Micro-Electronics (CREME96) code. Rate-calculation accuracy is checked using on-orbit data from the published literature. The implications for data collection are discussed. [ABSTRACT FROM AUTHOR]

Structural symmetries in the storage ring of synchrotrons are intentionally created during the design phase of the magnetic lattices, but they are rarely considered in the design of control algorithms that stabilize the beam of accelerated particles. The choice of control algorithm, however, is limited by the high actuation frequency and the large number of inputs and outputs. Standard control algorithms for synchrotrons are based on a singular value decomposition (SVD) of the orbit response matrix. SVD controllers neither exploit the structural symmetries nor exhibit any speed advantages. By considering the periodicity and the reflection properties of the betatron function, we show that these structural symmetries are inherited by the orbit response matrix. We then show that the resulting block-circulant and centrosymmetric properties of the matrix can be used for different computationally efficient decompositions of the controller. We also address the case of broken symmetry caused by odd placements of individual magnets and monitors. Our efficient decomposition enables the use of more advanced control techniques for synchrotrons, such as control algorithms that require real-time optimization. These advanced control techniques can in turn increase the stability of photon beams in synchrotron light sources. [ABSTRACT FROM AUTHOR]

An eight-year long flight database from an error detection and correction (EDAC) counter implemented onboard an altimeter flying on CryoSat-2 spacecraft at 715-km altitude is analyzed to investigate the impact of solar cycle variations on long-term effect predictions. In situ observations are then compared to various specification models including legacy models as well as models under developments. [ABSTRACT FROM AUTHOR]

This article presents the study of the drift of the South Atlantic Anomaly (SAA) based on data coming from the radiation monitor ICARE-NG. This instrument was integrated on several low earth orbit (LEO) satellites such as JASON 2 and JASON 3. NOAA-15 data are also studied to compare and confirm ICARE-NG measurements. Twenty years of data have been used for this article. The evolution of the maximum proton flux detected, and the SAA area and centroid of the SAA have also been investigated. [ABSTRACT FROM AUTHOR]

DArk Matter Particle Explorer (DAMPE), a satel- lite-based cosmic-ray (CR) and gamma-ray measurement experiment, relies on its calorimeter to measure the energy of incident particles. The calorimeter adopts crystals of bismuth germanium oxide (BGO) as scintillating material, and it is designed to aim for measurements of energy ranging from 50 GeV to 100 TeV in the case of a CR nucleus. This article concerns the response of the BGO calorimeter to nucleus-type CRs. CRs with very low energy can rarely reach the detector due to the Earth’s magnetic field. A cutoff on lower energy can be observed in the energy spectrum. In this article, the cutoff is used to study the response of the calorimeter. Carbon, neon, silicon, and iron are analyzed separately in comparison with Monte Carlo simulations by Geant4. [ABSTRACT FROM AUTHOR]

Proton-induced fission of high-Z materials can produce fluxes of high linear energy transfer (LET) ions that greatly exceed those from galactic cosmic ray (GCR) or even solar particle event (SPE) environments. These ions can pose significant threats to microelectronics. We develop methods to evaluate the risks for a range of destructive and nondestructive single-event effects (SEE) modes caused by this threat by evaluating the role of the proton environment, the amount and placement of high-Z materials and overburden in the part, and the sensitive volume geometry for the SEE modes under consideration. [ABSTRACT FROM AUTHOR]

A simple internal charging current monitor has been developed to monitor the penetration of energetic particles within spacecraft in geostationary orbits. The instrument, known as a charging monitor (CM), is a component of a suite of space weather instruments aboard the geostationary satellite GEO-KOMPSAT-2A (GK2A), that was successfully launched on December 4, 2018, with a final longitude of 128.2° E. The instrument measures the integral fluxes of charged particles through a 1-mm-thick aluminum wall, along with another 1-mm-thick aluminum plate, effectively collecting electron and proton currents with energies approximately above 0.6 and 13.1 MeV, respectively. Great care has been exercised in the design of the instrument to extend the lifetime of the analog electronics of the detector, which may easily become vulnerable to the harsh radiation environment of the outer electron belt in geostationary orbits. Comparisons of measurements from the CM have been made with those from particle detectors with a more sophisticated design from the same suite. Initial results of the CM operation for the first four months are presented, including a period of moderate geomagnetic storms. The comparisons clearly show that the CM is sufficiently capable of monitoring the enhanced levels of electrical currents from the penetration of high-energy charged particles in the context of space weather research with a minimal spacecraft resources cost and design efforts. [ABSTRACT FROM AUTHOR]

This article reports on the calculation of upset rates in geosynchronous orbit using a design of experiments (DOEs) and Monte-Carlo (MC) approach to the parameters available in CREME96. Accuracy of the approach is checked using on-orbit data from the published literature, and the implications for data collection are discussed. [ABSTRACT FROM AUTHOR]

We use electron flux derived from the environment monitoring unit “(EMU)-SURF” current monitor on board a Galileo Global Navigation Satellite System (GNSS) constellation satellite to modify and update the model of outer belt electrons for dielectric internal charging (MOBE-DIC). We describe how this data set, together with data from similar current–measuring instruments on Van Allen Probes, Giove-A, and STRV1d, are used to improve and expand the model. We have extended the spatial range to include the inner belt, exploited EMU data to widen the energy range for the electron spectrum, updated the statistical analysis of flux variation using a data set double the size used for the original model, and established a new and independent latitude function that yields improved agreement in medium earth orbit compared to the original model. The model is entirely characterized by a set of equations and parameters that produce fluxes as a function of magnetic coordinates at three distinct statistical levels. [ABSTRACT FROM AUTHOR]

This article reports the proton radiation sensitivity of two 1.0-mm-thick EURORAD ohmic CdTe detectors, irradiated with a low energy proton beam generated in a positron emission tomography (PET) cyclotron facility. The CdTe crystals were exposed to a proton radiation field composed of energies of $\approx 13.8$ , $\approx 9.7$ , $\approx 5.7$ , and $\approx 3.3$ MeV, at an average flux of ~ $10^{8}$ protons cm−2s−1, a total fluence from $\approx 2.1 \times 10^{9}$ up to $\approx 4.5 \times 10^{10}$ protons cm−2, and an average dose from $\approx 5.9$ up to $\approx 130$ Gy, equivalent to the proton fluence accumulated in ~1 up to ~20 years in a low earth orbit (LEO). The impact of the proton radiation field was analyzed through its charge transport properties—the mobility-lifetime product for electrons, ($\mu \tau $)e, and holes, ($\mu \tau $)h,—and spectroscopic properties—the energy resolution and the peak-to-valley ratio, for $\gamma $ -ray lines within 60–662 keV. The tested CdTe detectors, with ($\mu \tau $) $_{e} \sim 5 \times 10^{-4}$ cm2V−1 and ($\mu \tau $) $_{h} \sim 3\times \,\,10^{-5}$ cm2 V−1, showed good radiation hardness, with the measured upper-limit of ($\mu \tau $)e and ($\mu \tau $)h proton fluence (average dose) sensitivity of $\sim 2\times 10^{-15}$ cm2V−1/protons cm−2 ($\sim 7 \times 10^{-7}$ cm2 V−1/Gy) and $\sim 3 \times 10^{-16}$ cm2 V−1/protons cm−2 ($\sim 1 \times 10^{-7}$ cm2 V−1/Gy), respectively. Up to $\approx 130$ Gy, no significant degradation of the energy resolution and the peak-to-valley ratio was observed. [ABSTRACT FROM AUTHOR]

A new specification model of low-energy electrons fluxes, included in the Global Radiation Earth ENvironment (GREEN) model, has been developed at ONERA. This model is based on several data sets, from low altitudes with National Oceanic and Atmospheric Administration-Polar Operational Environmental Satellites measurements to higher altitudes with POLAR, THEMIS, and Los Alamos National Laboratory (LANL) measurements. It provides mean electron fluxes versus $L$ , $B/B _{\mathrm {eq}}$ , magnetic local time (MLT), and energy (for energies between 0.19 keV and few tens of kiloelectron volts). In this paper, the model is compared to AE9/SPM model and Van Allen Probe measurements. [ABSTRACT FROM AUTHOR]

The radiation environment of the Galileo spacecraft is severe and poorly characterized. The Galileo orbit takes the spacecraft through the heart of the outer radiation belt, while the low levels of geomagnetic shielding throughout the orbit expose the spacecraft to intermittent intense fluxes of protons during solar energetic particle events. In the Galileo constellation, two environmental monitoring units (EMUs) are currently flying in two different orbital planes. These units monitor the radiation environment and provide critical information related to hazards for the host spacecraft and its payload. In this paper, we present the results from the analysis of the surface charge collecting plates and the proton telescope sensors. The performed numerical calibration of the EMU sensors and the application of novel unfolding and in-flight cross-calibration techniques allow the calculation of high-quality proton and electron differential fluxes. The creation of a high-quality, long-term EMU electron flux data set, is a step forward toward the improved characterization of medium earth orbit (MEO) environment through the update of the existing or the development of new radiation environment models. [ABSTRACT FROM AUTHOR]

This paper describes a comparison between in-orbit single-event effects (SEE) rate measurement acquired by the CARMEN-3 experiment on-board the JASON-3 satellite (middle earth orbit, 1336 km, 66°) and an estimation using SEE rate calculation approaches from several facilities. A SRAM memory sensitive to single-event latchup (SEL) has been monitored in orbit, and the number of events per day was estimated using monoenergetic data coming from the Kernfysisch Versneller Instituut (protons) and Université Catholique de Louvain (heavy-ions) facilities as well as using mixed-field data coming from the Cern High energy AcceleRator Mixed field (CHARM) facility. A comparison of both estimations with respect to the in-flight measurement has been carried out. [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]

Review of space climatology is presented with a view toward spacecraft electronics applications. The origins and abundances of space radiations are discussed and related to their potential effects. Significant historical developments are summarized leading to the inception of space climatology and into the space era. Energetic particle radiation properties and models of galactic cosmic rays, solar energetic and geomagnetic trapped particles are described. This includes current radiation effects issues that models face today. [ABSTRACT FROM AUTHOR]

A CubeSat payload (PL) was designed at CERN and at the University Space Center of Montpellier, for the measurement of radiation and its effects on electronics and single event latchup recording on SRAM devices. The PL and the data handling modules were tested at the CERN mixed-field facility, in a Low Earth Orbit representative environment. [ABSTRACT FROM AUTHOR]

In-flight dark current nonuniformity measurements performed on three different satellites [JASON-2, SPRINT-A, and SAT-X (name withheld)] are compared to ground calculations. The standard deviation of the DCNU is calculated using both the AP8 and AP9 environment models. These predictions are compared to some calculations made with proton fluxes measured with the Influence sur les Composants Avancés des Radiations de l’Espace-NG spectrometer embedded on the JASON-2 satellite. The reliability of AP8 and AP9 models is analyzed. AP9 model appears to consistently overestimate the in-flight degradation. [ABSTRACT FROM AUTHOR]

By analyzing the newly released in situ data in medium earth orbit (MEO) of global positioning system satellites, we studied the spatiotemporal distribution and statistical characteristics of electrons over one solar cycle. The Weibull distribution of daily-averaged flux cumulative occurrence probability is proven. For >2-MeV electron flux, the determination coefficient of Weibull fitting is 99.92%. In the magnetic storm of late July 2004, the radial diffusion of electrons to low L-shell position was obvious. The center of 0.04-MeV electrons moved inward from $L = 6$ to $L = 4.3$ in the main phase and moved outward slowly in the recovery phase. In 0–4 MeV range, the in situ electron flux data are consistent with the AE9 mean and MEO-v2 model. The percentile of the AE9 model is also validated. The differential spectra are fitted based on exponential function at different percentiles. We also develop a rapid analysis method of internal charging in a changing electron environment. Using this method, we find that the electric field of internal charging fluctuates a lot because of the time-varying electron environment in MEO. The charging processes of different dielectrics (time constant ranges from 1 day to 100 days) in one solar cycle are also simulated. The longer the time constant, the bigger is the maximum charging electric field. But the worst case flux needed for discharging hazard evaluation is smaller. The daily-averaged worst case flux for charging assessment is not applicable. [ABSTRACT FROM AUTHOR]

Three hundred commercial off-the-shelf ADSP-2187L chips on AMS-02 have been operating without major problems on the International Space Station since launch. The conversion rates from the single event upset (SEU) to single event function interrupt varied with the operation methods. The correlation between the on-orbit SEU and radiation environments during the 24th solar cycle was studied. The on-orbit SEU rate was much lower than expected. Possible reasons for the higher predicted SEU rate were discussed and thought to be the different circuit operations of the ground test method and the on-orbit one in the sensitive linear energy transfer range. [ABSTRACT FROM PUBLISHER]

This paper describes version 1.5 of the AE9/AP9 family of space radiation climatology models. The most significant update is the inclusion of new data sets that change the flux maps. These new data include measurements from Van Allen Probes, Azur, and the HiLET sensor on the TWINS-2 spacecraft. In recognition of international contributions to the models, we introduce the IRENE nomenclature for International Radiation Environment Near Earth. [ABSTRACT FROM PUBLISHER]

Deep dielectric charging/discharging is a serious space environmental effect. Charging electric fields are the fundamental cause of dielectric discharging. In order to quantitatively mitigate deep dielectric charging effects, the GEANT4 toolkit and radiation-induced conductivity model were used to calculate the maximum possible internal charging potential and electric field with different shielding layer thicknesses, dielectric thicknesses, and ground types. The study selected electron spectra from geostationary earth orbit (GEO) and jupiter orbits as the input environment. With these calculations, a criterion for shielding, dielectric thickness, and ground types is provided such that spacecraft engineers may choose the appropriate method to decrease the deep dielectric charging effects. The charging time constants of flame retardant 4 and polytetrafluoroethylene are ~20 and 500 h, respectively, with a little dependence on input electron spectra, ground type, shield thickness, or dielectric thickness. The dielectric characteristics, ground types, and thicknesses, which can significantly change the value of the electric field, are critical for preventing deep dielectric charging. The maximum saturation charging potential and electric field at jupiter orbit are much larger than those at GEO. [ABSTRACT FROM PUBLISHER]

Electronic devices on the Van Allen Probes mission have experienced more than a thousand single-event effects (SEE) during the 4.5 years of transit through the inner and outer earth trapped radiation belts. The majority of these SEE have been due to trapped protons determined by the orbit timing and the dose rate response of the engineering radiation monitor. Fault tolerant systems engineering and spacecraft operation have enabled a successful mission to date without a safe mode or spacecraft emergency. [ABSTRACT FROM PUBLISHER]

A low-noise head amplifier has been developed for the extra low energy antiproton ring beam trajectory, orbit, and intensity measurement system at CERN. This system is based on 24 double-electrode electrostatic beam position monitors installed around the ring. A head amplifier is placed close to each beam position monitor to amplify the electrode signals and generate a difference and a sum signal. These signals are sent to the digital acquisition system, about 50 m away from the ring, where they are digitized and further processed. The beam position can be measured by dividing the difference signal by the sum signal while the sum signal gives information relative to the beam intensity. The head amplifier consists of two discrete charge preamplifiers with junction field effect transistor (JFET) inputs, a sum and a difference stage, and two cable drivers. Special attention has been paid to the amplifier printed circuit board design to minimize the parasitic capacitances and inductances at the charge amplifier stages to meet the gain and noise requirements. The measurements carried out on the head amplifier showed a gain of 40.5 and 46.5 dB for the sum and difference outputs with a bandwidth from 200 Hz to 75 MHz and an input voltage noise density lower than 400~\text pV/\surd \textHz . Twenty head amplifiers have been already installed in the ring and they have been used to detect the first beam signals during the first commissioning stage in November 2016. [ABSTRACT FROM AUTHOR]

A single event latchup (SEL) experiment based on commercial static random access memory (SRAM) memories has recently been proposed in the framework of the European Organization for Nuclear Research (CERN) Latchup Experiment and Student Satellite nanosatellite low Earth orbit (LEO) space mission. SEL characterization of three commercial SRAM memories has been carried out at the Paul Scherrer Institut (PSI) facility, using monoenergetic focused proton beams and different acquisition setups. The best target candidate was selected and a circuit for SEL detection has been proposed and tested at CERN, in the CERN High Energy AcceleRator Mixed-field facility (CHARM). Experimental results were carried out at test locations representative of the LEO environment, thus providing a full characterization of the SRAM cross sections, together with the analysis of the single-event effect and total ionizing dose of the latchup detection circuit in relation to the particle spectra expected during mission. The setups used for SEL monitoring are described, and details of the proposed circuit components and topology are presented. Experimental results obtained both at PSI and at CHARM facilities are discussed. [ABSTRACT FROM PUBLISHER]

In-flight feedback data are collected, such as displacement damage doses, ionizing doses, and cumulated Single Event upset (SEU) on board various space vehicles and are compared to predictions performed with: 1) proton measurements performed with spectrometers data on board the same spacecraft if any and 2) protons spectrum predicted by the legacy AP8min model and the AP9 and Onera Proton Altitude Low models. When an accurate representation of the 3-D spacecraft shielding as well as appropriate ground calibrations are considered in the calculations, such comparisons provide powerful metrics to investigate engineering model accuracy. To describe >30 MeV trapped protons fluxes, the AP8 min model is found to provide closer predictions to observations than AP9 V1.30.001 (mean and perturbed mean). [ABSTRACT FROM PUBLISHER]

This paper reports on in situ measurements of the linear energy transfer spectra of galactic cosmic rays and their progeny and of trapped Van Allen belt protons as recorded by a pulse height analyzer (PHA) radiation spectrometer which flew on the STS-95 DISCOVERY mission on the Hubble Orbital Systems Test cradle. The shuttle was launched on October 29, 1998 and had a mission duration of 8.5 days during the minimum phase of the solar activity cycle. The orbit of the STS-95 was about 550 km altitude and 28.5° inclination. Close agreement was seen between radiation environment model predictions and the measurements of the PHA. Agreement is obtained by considering the directionality of the radiation interacting with the shuttle structure. [ABSTRACT FROM PUBLISHER]

We introduce an approach aimed at prescreening COTS components according to their single-event effect (SEE) sensitivity for space missions in which a complete characterization of their individual response to protons and heavy ions is not feasible due to cost and time constraints. The method is applied to a set of SRAM memories for single-event upset (SEU) and single-event latchup (SEL) and the resulting expected SEE rates are compared with traditional approaches and in-flight data for a low-earth orbit polar and a geostationary orbit. Despite the limitations related to components with high-LET threshold and thick sensitive volumes, we conclude that the proposed method can be an efficient means of rejecting highly sensitive components or lots and performing the complete characterization only on passing devices. [ABSTRACT FROM PUBLISHER]

Variability of the space radiation environment is investigated with regard to parts categorization for total dose hardness assurance methods. It is shown that it can have a significant impact. A modified approach is developed that uses current environment models more consistently and replaces the radiation design margin concept with one of failure probability during a mission. [ABSTRACT FROM PUBLISHER]

An overview of cyclotron development in research laboratories worldwide and the impressive growth of commercial cyclotrons during the last 50 years are summarized. The role of the superconducting cyclotrons, the return of the synchrocyclotrons, the flourishing interest in the fixed field alternating gradient (FFAG), and finally the proposed design for 10-MW class cyclotrons are also presented. [ABSTRACT FROM PUBLISHER]

The outer electron belt poses a significant radiation hazard to spacecraft due to internal charging and dose effects. We present a new user-friendly model to characterise the worst-case environment built on data from the Giove-A spacecraft. We use instrument data based on a novel technique of direct charging current measurements, uncontaminated by protons and unaffected by dead-time, to create the model. The model provides integral or differential electron flux spectra with the following input parameters: percentile 90%, 99% or 100%; L-shell range 3–8; Magnetic Latitude (B/B_0) range 1–100; Energy range 0.5–3 MeV. Comparisons with other models and independent data sets show that our “Model of Outer Belt Electrons for Dielectric Internal Charging” (MOBE-DIC) provides a sound worst-case specification for mission planners and design engineers. We find that, in medium Earth orbit particularly, MOBE-DIC indicates a harder electron spectrum than either AE9 or FLUMIC. [ABSTRACT FROM PUBLISHER]

The INTEGRAL satellite was launched on October 17, 2002 and all on-board instruments are still operating successfully after more than 12 years, which represents more than a full solar cycle. This paper deals with the dose measured by 8 RadFETs mounted in 2 electronic boxes, which control the detector plane of the IBIS/ISGRI camera. These measurements are compared to what could be predicted before the launch, by using the dose profile, as determined by common space environment software, and also a detailed sectorial analysis of shielding materials around the RadFETs by means of a Monte-Carlo based model of the whole spacecraft. In this study, the sectorial analysis relies on the accurate knowledge of the geometry, as determined from the qualification model of the electronic box still in the lab. In order to take into account the orbit evolution with time, the dose profile is determined with yearly-averaged orbital parameters for each of the 12 years of measurements. The aim of this analysis is to estimate the possibility of releasing some margins for future projects. [ABSTRACT FROM PUBLISHER]

The Aerospace Corporation performed a study to determine whether static percentiles of AE9/AP9 can be used to approximate dynamic Monte Carlo runs for radiation analysis of spiral transfer orbits. Solar panel degradation is a major concern for solar-electric propulsion because solar-electric propulsion depends on the power output of the solar panel. Different spiral trajectories have different radiation environments that could lead to solar panel degradation. Because the spiral transfer orbits only last weeks to months, an average environment does not adequately address the possible transient enhancements of the radiation environment that must be accounted for in optimizing the transfer orbit trajectory. Therefore, to optimize the trajectory, an ensemble of Monte Carlo simulations of AE9/AP9 would normally be run for every spiral trajectory to determine the 95th percentile radiation environment. To avoid performing lengthy Monte Carlo dynamic simulations for every candidate spiral trajectory in the optimization, we found a static percentile that would be an accurate representation of the full Monte Carlo simulation for a representative set of spiral trajectories. For 3 LEO to GEO and 1 LEO to MEO trajectories, a static 90th percentile AP9 is a good approximation of the 95th percentile fluence with dynamics for 4-10 MeV protons, and a static 80th percentile AE9 is a good approximation of the 95th percentile fluence with dynamics for 0.5-2 MeV electrons. While the specific percentiles chosen cannot necessarily be used in general for other orbit trade studies, the concept of determining a static percentile as a quick approximation to a full Monte Carlo ensemble of simulations can likely be applied to other orbit trade studies. We expect the static percentile to depend on the region of space traversed, the mission duration, and the radiation effect considered. [ABSTRACT FROM PUBLISHER]

Low-thrust geostationary transfer orbits (LT2GEO) are found to offer significant low cost options thus making them very attractive for GEO missions. However, LT2GEOs increase the transfer orbit time from days to months, thereby causing a significant increase in the time that satellites traverse the most intense trapped particle radiation belts. This paper describes the LT2GEO radiation environment and provides some practical implications using new solar cell technologies and materials. New solar cell and coverglass testing protocols are established using Monte Carlo transport modeling and experimental results are given for Qioptiq CMG borosilicate coverglass. [ABSTRACT FROM PUBLISHER]

Measurements of the ICARE-NG/CARMEN-1 (Influence sur les Composants Avancés des Radiations de l’Espace-Nouvelle Génération/CARactérisatin et Modélisation de l’Environnement spatial) detector on board the low Earth orbit Argentinean satellite SAC-D are presented. Particle fluxes are obtained for electrons from 250 keV up to 3.2 MeV and protons from 12.8 MeV up to 190 MeV since September 2011. As the detector was placed on a side of the satellite which is directed 45^\circ from zenith, large anisotropy was observed in the measurements. Finally, making advantage of the 128 different channels, a singular value decomposition (SVD) method was used to reconstruct with a great precision the proton spectrum in the range 60-300 MeV, and extended it up to 600 MeV. [ABSTRACT FROM PUBLISHER]

In this work we present the development of the electron Slot Region Radiation Environment Model (e-SRREM). e-SRREM is a data-based statistical model which has been built on fifteen years of electron flux measurements. The model describes the trapped electron radiation in a region that includes the slot region between the inner and the outer electron radiation belts. The model provides energetic electron fluxes with their uncertainties determined by confidence levels for user-defined mission orbit and duration. First comparisons of e-SRREM with the AE8 and International Radiation Environment Near Earth (IRENE) AE9 models show that the aforementioned models underestimate the electron flux levels along highly elliptic orbit that crosses the slot region. Extensive testings and comparisons will follow in future work. [ABSTRACT FROM PUBLISHER]

A new model of electron flux in the Slot Region has been developed at ONERA. This model is based on several data sets, low altitudes data as POES or SAC-C measurements, but also data at higher altitudes as HEO1, HEO3, ICO and CRRES measurements. This model provides mean electron flux between L = 2 and L = 4 for energies between 0.1 MeV and 3 MeV. This model includes a confidence level which takes into account the dynamics of electron flux in the slot region. [ABSTRACT FROM PUBLISHER]

In the frame of the ONERA-CNES CRATERRE project, which aims to organize studies around radiation belt specification models, the local database Ionizing Particle ONERA Database (IPODE), gathering measurements from many radiation detectors, is presented. Relying on this daily updated database, two radiation belt activity indices with electron flux measurement (> \300~keV and > \1.6~MeV) and one solar proton event alarm with proton flux measurement (> \75~MeV) are developed for postevents analysis. Approach definition and validation are detailed for both indices and alarm. Those indicators are plotted over the last 30 days on the CRATERRE project website and are updated every day. [ABSTRACT FROM PUBLISHER]

Van Allen Probes A and B, launched more than a year ago (in August 2012), carried 16 p-channel metal-oxide-semiconductor Radiation-sensitive Field Effect Transistors (RadFET)s into an orbit designed by NASA to probe the heart of the trapped-radiation belts. Nearly 350 days of in situ measurements from the Engineering Radiation Monitor (ERM) 1) demonstrated strong variations of dose rates with time, 2) revealed a critical correlation between the ERM RadFET dosimeters and the ERM Faraday cup data on charged particles, and 3) permitted the mapping of the belts by measuring variation with orbit altitude. This paper provides an update on early results given in a NSREC2012 paper along with details and discussion of the RadFET dosimetry data analyzed . [ABSTRACT FROM PUBLISHER]

Knowledge of the static equilibrium orbit properties is crucial for cyclotron design and development. With the increase of computational speed, numerical orbit calculations are more and more often employed as a part of other methods. Direct numerical integration of the canonical equations of motion is used most often for orbit calculations. We propose an original method for the calculation of static equilibrium orbit properties by direct trajectory tracking in the real, configuration space, and compare it with the method most commonly used. [ABSTRACT FROM PUBLISHER]

The micro-computer ADSP21060 (Analog Device) of the DEMETER satellite experienced a number of anomalies referenced as Single Event Effects (SEE). The events recorded outside the south Atlantic anomaly are not correlated to solar flare protons. The two main potential causes of these anomalies are the SEUs induced by the cosmic rays and the electrostatic discharge pulses able to trigger within the ADSP21060 some transients analogous to a single event effect. Both hypotheses areanalysed. A correlation of the DEMETER’s anomalies with the particles fluxes of the space environment has been performed using the IPSAT toolkit refid="ref1"/. A direct comparison of the DEMETER’s anomalies is performed with the SEUs measured onboard the SAC-C satellite that flies on a similar orbit refid="ref2"/, refid="ref3"/ . The correlation with internal charging/discharging phenomenon is also investigated by means of a simple electrical potential calculation. [ABSTRACT FROM PUBLISHER]

The objective of this paper is to propose a predictive analysis based on MUSCA SEP3 including statistic properties, and to demonstrate the relevance of this approach if compared to real operational results. The method was validated by comparison with ground test results and statistical analyses were applied to in-flight data issued from the ICARE equipment (SAC-C satellite). In an operational context, results show that confidence level SEU-risk is relevant when conventional average calculations are deficient. This is particularly accurate when the solar flare is characterized by medium or low flux level. [ABSTRACT FROM AUTHOR]

For given arbitrary electromagnetic fields, an analytical method to obtain transfer coefficients up to the third order in phase-space coordinates is described in this paper. The method is based on numerical tracking of a number of representative particles followed by the least-square minimization. The result is applied to an arbitrary beamline consisting of linear and nonlinear beam-optical elements and favorably compared with the numerical particle tracking. Transfer coefficients obtained with our method are also compared with those obtained from an existing computer code. [ABSTRACT FROM AUTHOR]

This paper provides information regarding the use of the Xilinx Virtex-4 field-programmable gate array (FPGA) in a spacecraft deployed to low-earth orbit. The results are compared to pre-deployment accelerated single-event effects (SEEs) and fault-injection testing. [ABSTRACT FROM AUTHOR]

A consistent tool that completely characterizes the Earth's magnetic shielding at any location in space has been developed. The formalism of transmissivity helps the user to rapidly compute and estimate the transmitted SEP flux along any orbit. The model and first results (comparison to SAC-C/ICARE measurements) are presented. In particular, the geomagnetic shielding at GPS-like altitude is focused on and comparison plots of transmitted flux obtained when using different transmission functions for example orbits are analyzed. [ABSTRACT FROM AUTHOR]