Ionizing Radiation in Earth's Atmosphere and in Space Near Earth (original) (raw)
Related papers
A small active dosimeter for applications in space
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2014
ABSTRACT The radiation field in low Earth orbits (LEO) differs significantly from the radiation environment on Earth׳s surface. Exposures are by far higher and pose an additional health risk for astronauts. Continuous monitoring is therefore a necessary task in the frame of radiation protection measures. A small battery-driven active dosimeter telescope based on silicon detectors meeting the requirements for LEO applications has been developed. The instrument, the Mobile Dosimetric Telescope (MDT), is designed to measure the absorbed dose rate and the linear energy transfer (LET) spectra. From the latter the mean quality factor of the radiation field can be derived and hence an estimate of the dose equivalent as a measure of the exposure. The calibration of the device is done using radioactive isotopes and heavy ions. Fragmentation products of heavy ions are used to show the ability of the MDT to reliably detect energy depositions from high energetic nuclei. Radiation measurements inside aircraft during long distance flights, serving as field tests of the instrument, prove the good performance of the instrument.
Overview of energetic particle hazards during prospective manned missions to Mars
A scenario for an initial manned mission to Mars involves transits through the Van Allen Radiation Belts, a 30 day 'short surface stay' and a 400 day Cruise Phase (to/from the planet). The contribution to the total dose incurred through transiting the belts is relatively small and manageable. Estimates of the particle radiation hazard incurred during a 30 day stay on the surface (using ESA's Mars Energetic Radiation Environment Models dMEREM and e MEREM) indicate that the dose is not expected to be particularly challenging health-wise due to the shielding effect provided by the Martian atmosphere and the body of the planet. This is in accord with estimations obtained using the Langley HZETRN code. Estimates of GCR exposure in free space during the minimum phase of Solar Cycle 23 determined using the CREME2009 model are in reasonable agreement with published results obtained using HZETRN (which they exceed by about 10%). The Cruise Phase poses a significant radiation problem due to the cumulative effects of isotropic Galactic Cosmic Radiation over 400 days. The occurrence during this period of a large Solar Energetic Particle (SEP) event, especially if it has a hard energy spectrum, could be catastrophic health wise to the crew. Such particle events are rare but they are not currently predictable. An overview of mitigating strategies currently under development to meet the radiation challenge is provided and it is shown that the health problem posed by energetic particle radiation is presently unresolved.
Atmospheric Ionizing Radiation and Human Exposure
2004
Atmospheric ionizing radiation is of interest, apart from its main concern of aircraft exposures, because it is a principal source of human exposure to radiations with high linear energy transfer (LET). The ionizing radiations of the lower atmosphere tend to be dominated by the terrestrial radioisotopes especially along the costal plain and interior low lands and have only minor contributions
The Solar Radiation Alert (SRA) system continuously evaluates measurements of high-energy protons made by instruments on GOES satellites. If the measurements indicate a substantial elevation of effective dose rates at aircraft flight altitudes, the Civil Aerospace Medical Institute issues an SRA via the National Oceanic and Atmospheric Administration Weather Wire Service. This report describes a revised SRA system. SRA issue-criteria remain the same but significant improvements have been made in the calculations. The solar proton fluence to effective dose conversion coefficients have been recalculated using 2007 recommendations of the International Commission on Radiological Protection and the latest release of the Monte Carlo transport code, MCNPX 2.6.0. The shape of the <10 MeV secondary neutron spectrum is now accounted for down to 100 eV. The flux correction based on spectral index has been revised to smooth the flux spectrum of solar protons. Estimates of the >605 MeV spe...