1. Air Crew Hazards and Safety: FAA Uses of Neutron Monitor Data in Aviation Radiation Safety Presented by Kyle A. Copeland, Ph.D. 2015 Neutron Monitor Community Workshop 24-25 October 2015 1 http://www.faa.gov/data_research/research/med_humanfacs/aeromedical/radiobiology/ E-mail: Kyle.Copeland@faa.gov

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3. Ten highest average annual effective doses among monitored workers worldwide (1990-1994) [UNSCEAR, 2000]. 3 The annual dose for aircrew will increase as the average flight altitude increases! In 2012 there were about 200,000 US crewmembers (U.S. BLS).

4. Ionizing Radiation in Aviation <0.13 mSv <30 mSv per event, rare <6 mSv, primary source <10 mSv per event, rare 4

5. Stochastic and Deterministic Effects Increased lifetime risk* Stochastic EffectWhole population Age group 18-64 years Genetic defect in first or second generation (child or grandchild) following irradiation before conception 0.4 in 100,000 per mSv 2.4 in 1,000,000 per mSv Cancer (non-fatal or fatal) 34 in 100,000 per mSv 23 in 100,000 per mSv Cancer (fatal only) 8.0 in 100,000 per mSv6.3 in 100,000 per mSv *Risks assumes exposure to high-LET radiation (i.e., no DDREF) [ICRP Pub. 103] Deterministic Effect Threshold Dose None Significant <0.1 Gy Risks to conceptus (mental retardation, malformation, etc.) 0.1-0.5 Gy Transient mild nausea and headache in adults 0.35 Gy Effective Dose Limits for Workers Pregnant 1 mSv for duration of pregnancy and 0.5 mSv per month Other 100 mSv per 5 years and no more than 50 mSv in any one year 5

6. 1.The heliosphere 2. Solar wind 6 Galactic Cosmic Radiation: How does it get here? Source: NASA Shea and Smart, 2001

7. Earth’s Atmosphere For aviation, the practical boundary of the atmosphere is 100 km (328,000 ft) 78% nitrogen 21% oxygen 0.93% argon 0.034% (average) carbon dioxide trace amounts of other gases 7

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9. Galactic Cosmic Radiation Levels, January 1958 through December 2008 10 http://notrickszone.com/2012/12/05/brutal-cold-headed-for-europe- and-north-america-solar-and-ocean-cycles-bode-of-an-approaching- little-ice-age/#sthash.GG7K40fN.dpbs Percent, % 10

10. Solar Dose Rates During an SPE, cosmic ray spectrum modelling is more complex. -The particle spectra are constantly changing. -GOES satellite instruments provide good data for protons up to about 1 GV, but not higher energies. -Isotropy of incident cosmic ray flux is often a poor assumption, particular at the start of events when fluxes are usually highest. -To provide a good picture of anisotropy, a world grid of neutron monitors is needed. Data from many monitors is needed to maximize accuracy of post-event assessments. http://www.dtic.mil/dtic/tr/fulltext/u2/a235394.pdf (Smart and Shea, 1990) http://neutronm.bartol.udel.edu/listen/main.html#tell 10

11. Summary: Why Neutron Monitors Matter Galactic Cosmic Radiation - NMs are used for observing solar modulation in real time. - High resolution (hourly) data covers practically the entire jet age of civilian flight (starting in the late 1950s). - Useful for both long-term monitoring (solar cycle) and short-term variations (Forbush effects). - One monitor is enough, if statistics are really good. Solar Cosmic Radiation - Need multiple monitors at different altitudes and geomagnetic latitudes, both N and S. - NM data, along with GOES data, are the basis for calculation of SPE intensities. - Provide the best data for anisotropy calculations needed to drive more sophisticated SPE flight dose models. - Provide the best insight into multi-GeV proton and alpha spectra during a SPE, satellite instruments do not have enough shielding to discriminate well. 11