SYNCHROTRON RADIATION CALCULATIONS FOR THE ARTIFICIAL RADIATION BELT
Angular distributions of electrons and sychrotron radiation in artificial radiation belt, and sky temperature calculations from electron flux
SYNCHROTRON RADIATION↗
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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Explorer 12 observations of the temporal variations of low-energy electron intensities in the outer radiation zone during geomagnetic storms.
Temporal variations of electron energy flux in outer radiation zone measured during geomagnetic activity with instrumentation on board Explorer XII satellite
EXPLORER XII SATELLITE↗
Plasma effects on the spontaneous emission of synchrotron radiation from weakly relativistic electrons
A method for computing the spectral emissivity of spontaneous synchrotron radiation is discussed. The Klimontovich (1967) formalism in plasma kinetic theory is adopted in which an ensemble average of the microscopically emitted power is considered. The present method clarifies the meaning of the random phase approximation which is imposed in several existing theories of synchrotron radiation. Both the effects of dielectric polarization and two-particle correlations are included in the present discussion. The theory is applied to the case of a plasma in thermal equilibrium, for which it is shown that the effect of pair correlations on the emissivity vanishes. On the other hand, the effect of dielectric polarization is studied numerically for a wide range of parameters.
Freund, H. P.↗
The action of a dietary retinoid on gene expression and cancer induction in electron-irradiated rat skin
Current models of radiation carcinogenesis generally assume that the DNA is damaged in a variety of ways by the radiation and that subsequent cell divisions contribute to the conversion of the damage to heritable mutations. Cancer may seem complex and intractable, but its complexity provides multiple opportunities for preventive interventions. Mitotic inhibitors are among the strongest cancer preventive agents, not only slowing the growth rate of preneoplasias but also increasing the fidelity of DNA repair processes. Ionizing radiation, including electrons, is a strong inducer of cancer in rat skin, and dietary retinoids have shown potent cancer preventive activity in the same system. A non-toxic dietary dose of retinyl acetate altered gene expression levels 24 hours after electron irradiation of rat skin. Of the 8740 genes on an Affymetrix rat expression array, the radiation significantly (5 fold or higher) altered 188, while the retinoid altered 231, including 16 radiation-altered genes that were reversely altered. While radiation strongly affected the expression of stress response, immune/inflammation and nucleic acid metabolism genes, the retinoid most strongly affected proliferation-related genes, including some significant reversals, such as, keratin 14, retinol binding protein, and calcium binding proteins. These results point to reversal of proliferation-relevant genes as a likely basis for the anti-radiogenic effects of dietary retinyl acetate.
Non-NASA Center↗
Secondary galactic electrons.
Energy spectrum of secondary galactic electrons obtained by kinematic transformation based on model of high energy collisions
HIGH ENERGY ELECTRON↗
Radiation physics research at MSFC
Nuclear and space radiation effects on materials and components used in space vehicles
SPACE RADIATION↗
Radiation damage of ordered vanadium pentacarbide by electron microscope beam bombardment
Radiation damage of vanadium carbide lattice by electron microscope beam bombardment
Lye, R. G.↗
Radiation design criteria handbook
Radiation design criteria for electronic parts applications in space environments are provided. The data were compiled from the Mariner/Jupiter Saturn 1977 electronic parts radiation test program. Radiation sensitive device types were exposed to radiation environments compatible with the MJS'77 requirements under suitable bias conditions. A total of 189 integrated circuits, transistors, and other semiconductor device types were tested.
Stanley, A. G.↗
Numerical simulations of bursty radio emissions from planetary magnetospheres
One-dimensional electromagnetic particle simulations are used to investigate the characteristics of radiation from electron beams with a large temperature anisotropy, in order to identify the origin of the smooth and bursty radio emissions from Uranus and Neptune observed by the Voyager spacecraft. It is shown that these electron beams, which would typically originate from the sporadic or impulsive injections of energetic electrons, can generate electromagnetic radiation which should be able to escape into the solar wind despite the growth of the electrostatic instability. The amount of radiation with frequencies above the local x mode cutoff increases with the beam speed. It is also proposed that some of the radiation generated below the local x mode cutoff may also be able to escape the plasma and be detected remotely via mode conversion between regions where field-aligned currents produce local perturbations in the magnetic field.
Winglee, R. M.↗
Compendium of Single Event Effect Results from NASA Goddard Space Flight Center
We present the results of single event effect (SEE) testing and analysis investigating the effects of radiation on electronics. This paper is a summary of test results.
digital↗
Quantitative Assessment of Risk for Modeling Radiation Impact on System Functions
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probabilistic risk assessment↗
1986 Annual Conference on Nuclear and Space Radiation Effects, 23rd, Providence, RI, July 21-23, 1986, Proceedings
The present conference on the effects of nuclear and space radiation on electronic hardware gives attention to topics in the basic mechanisms of radiation effects, dosimetry and energy-dependent effects, electronic device radiation hardness assurance, SOI/SOS radiation effects, spacecraft charging and space radiation, IC radiation effects and hardening, single-event upset (SEU) phenomena and hardening, and EMP/SGEMP/IEMP phenomena. Specific treatments encompass the generation of interface states by ionizing radiation in very thin MOS oxides, the microdosimetry of meson energy deposited on 1-micron sites in Si, total dose radiation and engineering studies, plasma interactions with biased concentrator solar cells, the transient imprint memory effect in MOS memories, mechanisms leading to SEU, and the vaporization and breakdown of thin columns of water.
Ellis, Thomas D.↗
Absolute electron fluxes and energies in the inner radiation zone in 1965.
Electron flux intensities and energy spectra in inner radiation zone, noting decay constants
Chapman, M. C.↗
Compton Gamma Ray Observatory/BATSE observations of energetic electrons scattered by cyclotron resonance with waves from powerful VLF transmitters
To obtain a better understanding of the wave-particle mechanisms responsible for the loss of electrons from the radiation belts, energetic electron data from the Burst and Transient Source Experiment (BATSE) on the NASA's Compton Gamma Ray Observatory (GRO) was studied. Powerful ground-based VLF transmitters resonantly scatter electrons from the inner radiation belt onto trajectories from which they precipitate into the atmosphere as they drift eastward. 563 instances in which the satellite traversed a cloud of energetic electrons which had been scattered into quasi-trapped trajectories were identified. From the longitude distribution, it was concluded that waves from the VLF transmitter NWC at 114 deg E are the origin of 257 of the events, and waves from UMSat 44 deg E related to 45 more. In another 177 cases the electrons had drifted from the longitude of these transmitters to a location in the western hemisphere. The previously reported seasonal variation in the frequency of occurrence of cyclotron resonance interaction is confirmed with the continuous coverage provided by GRO. The frequency of occurrence of the cyclotron resonance interactions is largest before sunrise, which we attribute to the diurnal variations in the transmission VLF waves through the ionosphere. For the first time, unique very narrow sheets of electrons occurring in the aftermath of a large geomagnetic storm are reported.
Datlowe, Dayton W.↗
The origin of the Galactic center annihilation radiation
Observations of the positron-electron annihilation radiation from the Galatic Center suggest that something truly extraordinary is occurring there. The observations of the intense, time-varying, 0.511-MeV emission are reviewed, and the implications of these and other recent observations on the positron production process, the annihilation region and the fundamental nature of the Galactic Center Source are discussed.
Lingenfelter, R. E.↗
Monte Carlo Study of the Formation of Chromosome Aberrations by Direct Ion Traversal vs. Delta-Electrons
Space radiation constitutes a major risk for the safety of space travel. Galactic Cosmic Rays (GCRs) are made of high energy protons (87%), high energy helium ions (12%) and high-charge and energy (HZE) ions [1]. At a cellular scale, HZE ions display a characteristic pattern of energy deposition, known as the ion track, that correlates with the ion linear energy transfer (LET). These energy deposition events (ionizations/excitations) create DNA breaks that, if misrepaired, lead to the formation of chromosome aberrations (CAs). Compared to low-LET terrestrial radiations (X-rays and γ-rays), high LET ions are known to create complex, clustered DNA breaks that are particularly efficient at forming CAs. Indeed, ion tracks are usually described as a dense ionization core, where clustered breaks are formed, and a penumbra, made of low-LET δ-electrons that have sufficient energy to travel across many cells and induce breaks that are more homogeneously distributed. In this work, we investigated the formation of CAs, and separated them into two contributions (direct ion traversal of the nucleus vs.δ-electrons), to elucidate to which extent δ-electrons contribute to CA formation.
Floriane Poignant↗
Space Radiation Environments Overview for MSFC Programs
Provide overview of Space Radiation Sources, Environments, Interactions with Electronic Devices - Radiation Sources - Solar Energetic Particles (SEP) and Solar Particle Events (SPE) - Galactic Cosmic Rays (GCR) - Radiation Environments - Van Allen belts - Beyond the belts - Reference SLS-SPEC-159 Rev G: Design Specification for Natural Environment (DSNE) - Interactions with Electronic Devices - Ionizing - Nonionizing - Internal Charging
Radiation Sources↗
Secondary positrons and electrons in the cosmic radiation
An improved calculation of the secondary production and equilibrium spectrum of positrons and electrons in the Galaxy in the energy range from 1 MeV to 100 GeV has been performed. This has been done by obtaining an analytic representation of the accelerator data which describes accurately the invariant cross-section of pions, kaons, and their antiparticles from threshold energy to about 1500 GeV. This calculation takes into account the correct angular distribution of electrons in the decay of muons and the effect of nuclei-nuclei collisions. The contributions of beta-decay positrons and knock-on electrons have been included. A comparison of the present calculations with earlier calculations and experiment is presented.
Badhwar, G. D.↗