A5087497797- Ionosphere and magnetosphere dynamics
- Solar and Space Plasma Dynamics
- Radiation Effects in Electronics
- Radiation Therapy and Dosimetry
- Astro and Planetary Science
- Spacecraft Design and Technology
- Space Satellite Systems and Control
- Space exploration and regulation
- Earthquake Detection and Analysis
- Radiation Detection and Scintillator Technologies
- Planetary Science and Exploration
- Atmospheric Ozone and Climate
- Graphite, nuclear technology, radiation studies
- Radioactivity and Radon Measurements
- Particle Detector Development and Performance
- Nuclear Issues and Defense
- Geomagnetism and Paleomagnetism Studies
- CCD and CMOS Imaging Sensors
- VLSI and Analog Circuit Testing
- Radioactive contamination and transfer
- Space Technology and Applications
- Nuclear Physics and Applications
- Integrated Circuits and Semiconductor Failure Analysis
- Spacecraft and Cryogenic Technologies
- Air Traffic Management and Optimization
University of Surrey
2015-2024
Surrey Satellite Technology (United Kingdom)
2019
University of Colorado Boulder
2019
Rutherford Appleton Laboratory
2019
Kyushu University
2019
The Aerospace Corporation
2019
Computational Physics (United States)
2019
Institute of Geology and Geophysics
2019
Chinese Academy of Sciences
2019
Qinetiq (United Kingdom)
2002-2012
Abstract Severe space weather was identified as a risk to the UK in 2010 part of wider review natural hazards triggered by societal disruption caused eruption Eyjafjallajökull volcano April that year. To support further assessment government officials, and at their request, we developed set reasonable worst‐case scenarios first published them technical report 2012 (current version 2020). Each scenario focused on environment could disrupt particular national infrastructure such electric power...
Abstract. It is important to appreciate how the morphology of internal charging spacecraft systems, due penetrating electrons, differs from that more common surface charging, electrons with lower energy. A specific and recurrent anomaly on a geostationary communication satellite has been tracked for ten years so solar cycle seasonal dependencies can be clearly established. Concurrent measurements sunspot number, wind speed 2-day >2 MeV electron fluence are presented highlight pertinent...
Abstract High‐energy trapped electrons in the Van Allen belts pose a threat to survivability of orbiting spacecraft. Two key radiation effects are total ionizing dose and displacement damage components materials, both which cause cumulative largely irreversible damage. During an extreme space weather event, electron fluxes can increase by several orders magnitude intensity, leading enhanced risk satellite failure. We use environments generated modeling statistical analyses estimate...
Data from ground-level radiation monitors and cosmogenic nuclides are combined to give a probability distribution for severe events related the well quantified event of February 23, 1956. Particle fluxes, single effects rates, dose rates calculated ground level aerospace systems. The 1956 would provide challenge air safety while more extreme seen in historical records safety-critical A new space weather hazard scale based on this could be used rapid assessment using high-latitude neutron...
The NASA Radiation Dosimetry Experiment (RaD-X) stratospheric balloon flight mission obtained measurements for improving the understanding of cosmic radiation transport in atmosphere and human exposure to this ionizing field aircraft environment. value dosimetric from platform is that they can be used characterize ray primaries, ultimate source aviation exposure. In addition, detectors were flown assess their potential application long-term, continuous monitoring RaD-X was successfully...
Satellite charging is one of the most important risks for satellites on orbit. can lead to an electrostatic discharge resulting in component damage, phantom commands, and loss service exceptional cases total satellite loss. Here we construct a realistic worst case fast solar wind stream event lasting 5 days or more use physical model calculate maximum electron flux greater than 2 MeV geostationary We find that tends toward value 106 cm-2·s-1·sr-1 after remains high another days. The...
Eight commercially available n-channel power MOSFETs were exposed to high energy spallation neutrons and thermal in separate experiments. Single event burnout (SEB) was observed several of the devices both environments. Measurements SEB at derated drain-source voltages show very strong reductions cross-sections, but suggest that current recommendations for safe operation may need updating voltage devices. In one device a different failure mode observed, with subsequent investigations...
Various SRAM and MOSFET devices were exposed to 3 MeV 14 neutrons at a fusion facility fission neutron spectrum with californium-252 source. Single event burnout (SEB) was observed in several of the MOSFETs all three environments-the first time this phenomenon has been energies below 10 MeV. In addition observing single upsets (SEU) latchup (SEL) SRAMs, two experienced significant multiple cell upset (MCU) effects which dominated rate. The physical mechanisms underlying these phenomena...
Air safety is tied to the phenomenon of ionizing radiation from space weather, primarily galactic cosmic rays but also solar energetic particles.A global framework for addressing issues in this environment has been constructed, more must be done at international and national levels.Health consequences atmospheric exposure are likely exist.In addition, severe events may cause economic aviation community due limits being reached by some crew members.Impacts a upon avionics high-energy...
Abstract Significant increases to the atmospheric radiation environment are recorded by a network of ground level neutron monitors as enhancements (GLEs). These space weather phenomena pose risk aviation via single event effects in aircraft electronics and ionizing dose passengers crew. Under UK Space Weather Instrumentation, Measurement, Modeling Risk programme, we have developed new model provide nowcasts environment, including both galactic cosmic ray (GCR) background during GLE events....
New radiation monitors based on solid-state detectors have been developed to perform wide-ranging measurements of the atmospheric environment and provide warnings sudden increases during solar particle events. Results obtained current deep minimum across full range latitudes from sea level 13 km altitude. for ambient dose equivalent agree very closely with Tissue Equivalent Proportional Counters carried same flights. Values 10 ¿Sv/hr are being reached at 12 altitude high latitude....
The Galileo global navigation system will employ an array of satellites in medium Earth orbit (MEO). Internal charging is one the primary hazards for any spacecraft MEO, and accordingly, test satellite, Giove-A, carries a detector, SURF, to undertake measurement internal currents at three different shielding depths. are due electrons stopped aluminum plates: first plate 0.5 mm thick located under 0.5-mm Al-equivalent shielding, second underneath plate, third 1.0 plate. Giove-A was...
The SURF internal charging monitor that measures deposited currents in three shielded aluminum plates is one of the sensors within Merlin radiation monitoring instrument launched on Giove-A December 2005 into a 23300-km circular 56° inclination medium earth orbit. has now completed 8.5 years orbit despite being originally intended for two-year operational life. Here, we report instrument's health, provide further recent data, and review overall results terms their engineering significance....
The radiation environment of the Galileo spacecraft is severe and poorly characterized. orbit takes through heart outer belt, while low levels geomagnetic shielding throughout expose to intermittent intense fluxes protons during solar energetic particle events. In constellation, two environmental monitoring units (EMUs) are currently flying in different orbital planes. These monitor provide critical information related hazards for host its payload. this paper, we present results from...
The NASA Radiation Dosimetry Experiment (RaD-X) successfully deployed four radiation detectors on a high-altitude balloon for period of approximately 20 h. One these was the RaySure in-flight monitor, which is solid-state instrument designed to measure ionizing dose rates aircrew and passengers. Data from RaD-X show absorbed rising steadily as function altitude up peak at 60,000 feet, known Pfotzer-Regener maximum. Above this level off before showing small decline approaches its maximum...
The upper atmosphere is a transition region between the neutron-dominated aviation environment and satellite where primary protons ions dominate. We report high altitude balloon measurements model results characterising this radiation for single event effects (SEE) in avionics. Our data, from RaySure solid-state monitor, reveal markedly different profiles low linear energy transfer (LET) LET depositions. use models to show that difference caused by influence of cosmic ray particles, which...
Abstract Ground level enhancements (GLEs) are space weather events that pose a potential hazard to the aviation environment through single event effects in avionics and increased dose passengers crew. The existing ground neutron monitoring network provides continuous well‐characterized measurements of radiation environment. However, there only few dozen active stations worldwide, has not been UK‐based station for several decades. Much smaller detectors increasingly deployed throughout world...
Within the next decade it is likely that space tourism industry will grow dramatically and number of humans travelling into, beyond, stratosphere via commercial entities such as World View Space Perspective increase. Current ventures focus on long duration very high altitude balloon flights; also known 'near space' flights, sub-orbital flights visits to Low Earth Orbit (LEO). In few decades ultimately become routine. During these new effects cosmic radiation exposure, especially during...
Sets of image frames were captured from a CCD device exposed to continuous beams high energy neutrons. The tracks short-range fragments nuclear spallation interactions in the silicon device's pixels have been analyzed respect their frequency, intensity, directionality and other pertinent parameters. A comparison between these results predictions computer code models nucleon is presented. Comparisons are also made with equivalent images neutron events an APS camera.
The outer electron belt poses a significant radiation hazard to spacecraft due internal charging and dose effects. We present new user-friendly model characterise the worst-case environment built on data from Giove-A spacecraft. use instrument based novel technique of direct current measurements, uncontaminated by protons unaffected dead-time, create model. provides integral or differential flux spectra with following input parameters: percentile 90%, 99% 100%; L-shell range 3-8; Magnetic...
Within the next decade it is likely that space tourism industry will grow and number of humans travelling into via commercial entities such as Virgin Galactic Blue Origin, increase significantly. Current ventures focus on short duration sub-orbital flights visits to Low Earth Orbit (LEO). In few decades, a journey could become normal transatlantic flight. During these new ventures, effects cosmic radiation exposure, especially during sudden changes in weather, ground level enhancement (GLE)...
Abstract AniMAIRE (Anisotropic Model for Atmospheric Ionising Radiation Effects) is a new model and Python toolkit calculating radiation dose rates experienced by aircraft during anisotropic solar energetic particle events. expands the physics of MAIRE + such that rate calculations can be performed conditions supplying proton or alpha rigidity spectrum, pitch angle distribution, Earth's magnetosphere. In this paper, we describe algorithm top‐level structure showcase AniMAIRE's capabilities...
The radiation monitors on board the Galileo Giove-A satellite, CEDEX and Merlin, their data are presented. instruments include energetic proton ion detectors, an internal charging monitor, RADFETs experimental dose-rate photodiodes. A comparison of with existing models is
Internal charging caused by energetic electrons is a threat to critical space infrastructure such as Europe's Galileo navigation satellites, however, the mechanism involved and its relationship weather still poorly understood. While electric field developed inside on-board dielectrics accepted be of prime importance, it has never been measured in orbit. On other hand, internal currents have now GPS-like medium Earth orbit (MEO) over ten-year period, so we used these data model fields...