Advances in Measuring and Modeling the Atmospheric Radiation Environment

Dyer, C. S.; Hands, A.; Lei, F.; Truscott, P.R.; Ryden, Keith; Morris, P. A.; Getley, I. L.; Bennett, L. G. I.; Bennett, B.; Lewis, Brent J.

doi:10.1109/tns.2009.2032185

Cited by 32 publications

(26 citation statements)

References 14 publications

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“…The environment at commercial aviation altitudes has been well studied because of the exposure of large numbers of passengers and aircrew [e.g., Tobiska et al, ; Ploc et al, ]. Regulations vary from country to country but it is a common practice, at least in Europe and the US, that dose to aircrew is taken into account by the relevant authorities and efforts are made to ensure that annual accumulated dose does not exceed safety thresholds [ Dyer et al, ]. This is almost invariably achieved through the use of radiation environment models rather than calibrated in situ measurements [ Bottollier‐Depois et al, ].…”

Section: Introductionmentioning

confidence: 99%

The disappearance of the pfotzer-regener maximum in dose equivalent measurements in the stratosphere

2016

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The NASA Radiation Dosimetry Experiment (RaD‐X) successfully deployed four radiation detectors on a high‐altitude balloon for a period of approximately 20 h. One of these detectors was the RaySure in‐flight monitor, which is a solid‐state instrument designed to measure ionizing dose rates to aircrew and passengers. Data from RaySure on RaD‐X show absorbed dose rates rising steadily as a function of altitude up to a peak at approximately 60,000 feet, known as the Pfotzer‐Regener maximum. Above this altitude absorbed dose rates level off before showing a small decline as the RaD‐X balloon approaches its maximum altitude of around 125,000 feet. The picture for biological dose equivalent, however, is very different. At high altitudes the fraction of dose from highly ionizing particles increases significantly. Dose from these particles causes a disproportionate amount of biological damage compared to dose from more lightly ionizing particles, and this is reflected in the quality factors used to calculate the dose equivalent quantity. By calculating dose equivalent from RaySure data, using coefficients derived from previous calibrations, we show that there is no peak in the dose equivalent rate at the Pfotzer‐Regener maximum. Instead, the dose equivalent rate keeps increasing with altitude as the influence of dose from primary cosmic rays becomes increasingly important. This result has implications for high altitude aviation, space tourism and, due to its thinner atmosphere, the surface radiation environment on Mars.

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Section: Introductionmentioning

confidence: 99%

The disappearance of the pfotzer-regener maximum in dose equivalent measurements in the stratosphere

2016

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“…A key condition for enabling all stakeholders to maximize their contributions in exposure mitigation is having quality dose measurements at altitude and emphasizing measurements at latitudes where the highest risks exist. Numerous measurements have been made and used for postflight analysis [ Dyer et al , ; Beck et al , ; Kyllönen et al , ; EC Radiation Protection 140 , ; Getley et al , ; Beck et al , ; Latocha et al , ; Meier et al , ; Beck et al , ; Dyer et al , ; Hands and Dyer , ; Getley et al , ; Gersey et al , ; Tobiska et al , ], although the vast majority are for background conditions and not during major space weather events. Some of these have made neutron flux and dose equivalent measurements with solid‐state detectors [ Dyer et al , ; Hands and Dyer , ; Tobiska et al , , ].…”

Section: Research Data Collectionmentioning

confidence: 99%

Advances in Atmospheric Radiation Measurements and Modeling Needed to Improve Air Safety

Tobiska¹,

Atwell²,

Beck³

et al. 2015

Space Weather

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Air safety is tied to the phenomenon of ionizing radiation from space weather, primarily from galactic cosmic rays but also from solar energetic particles. A global framework for addressing radiation issues in this environment has been constructed, but more must be done at international and national levels. Health consequences from atmospheric radiation exposure are likely to exist. In addition, severe solar radiation events may cause economic consequences in the international aviation community due to exposure limits being reached by some crew members. Impacts from a radiation environment upon avionics from high-energy particles and low-energy, thermalized neutrons are now recognized as an area of active interest. A broad community recognizes that there are a number of mitigation paths that can be taken relative to the human tissue and avionics exposure risks. These include developing active monitoring and measurement programs as well as improving scientific modeling capabilities that can eventually be turned into operations. A number of roadblocks to risk mitigation still exist, such as effective pilot training programs as well as monitoring, measuring, and regulatory measures. An active international effort toward observing the weather of atmospheric radiation must occur to make progress in mitigating radiation exposure risks. Stakeholders in this process include standard-making bodies, scientific organizations, regulatory organizations, air traffic management systems, aircraft owners and operators, pilots and crew, and even the public. Aviation Radiation Is an Unavoidable Space Weather PhenomenonAir safety has improved significantly in many meteorological areas over the past decades with the exception of space weather, which includes ionizing radiation. While a framework for addressing radiation issues has been constructed, we believe that more can and must be done at international and national levels. In particular, measurement programs must be expanded and linked with models to provide current epoch and, eventually, forecast information for the aviation ionizing radiation environment. A diverse radiation measurement and modeling community exists with a strong interest in improving international air safety.There are two challenges in our ever more mobile, technologically dependent global society. First, pilots, crew, and passengers, which include fetuses between their first and second trimesters, might face additional radiation hazards in terms of dose equivalent rate (rate of absorbed dose multiplied by the quality factor), particularly when flying at commercial aviation altitudes above 26,000 ft. (7924.8 m) (8 km) (see Figure 1). Second, avionics can experience single event effects (SEEs) from both the ambient high-energy and thermal neutron environments. The source of this radiation in either case is twofold-from the continuous bombardment by primary background galactic cosmic rays (GCRs) and also from solar energetic particles (SEPs) emitted during occasional solar flare events lasting up to a ...

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“…From Figure 3, the public/prenatal limit can be exceeded in 100 hours of flight time. For high-latitude and polar flights, the dose equivalent rate is on the order of ∼ 10 uSv/hr (Copeland et al, 2008;Dyer et al, 2009;Mertens et al, 2008;). An accumulated 100 hours of flight time can be accrued from 10-20 international flights with roughly 5-10 hours of flight time per flight.…”

Section: Commercial Aircraft Radiation Exposurementioning

confidence: 99%

“…However, aircrew are the only occupational group exposed to unquantified and undocumented levels of radiation. Furthermore, the current guidelines for maximum public and prenatal exposure can be exceeded during a single solar storm event for commercial passengers on intercontinental or cross-polar routes, or by frequent use (∼ 10-20 flights per year) of these high-latitude routes even during background conditions (AMS, 2007;Copeland et al, 2008;Dyer et al, 2009). …”

Section: Introductionmentioning

confidence: 99%