Aircrew and Spacecrew Radiation Exposure “The Dangers of Getting High” B.J. Lewis Royal Military College of Canada
Ottawa Chapter, Canadian Nuclear Society Ottawa, Ontario April 16, 2009
Outline z Aircrew Radiation Exposure Assessment z
Measurements and Computer Code Development
z Space Radiation Monitoring
Typical Annual Radiation Exposure Total Average Annual Exposure 3.6 mSv
Impetus • ICRP-60 (1990) and ICRP-103 (2007): – Reduce radiation exposure limits: • Nuclear Energy Worker (NEW): 50 to 20 mSv/year • Public: 5 to 1 mSv/year
– Recognize occupational exposure of aircrew to radiation
Aircrew Radiation Regulation • European Union (Basic Safety Standard Directive, May 2000)
• Canada (Transport Canada, Commercial and Business Aviation Advisory Circular, April 2001) – Account for exposure for >1 mSv/y (> 8 km) • • • •
Assess exposure Adjust working schedules (> 6 mSv action level) Inform workers Control doses during pregnancy (1 Other 3% Q=1 93%
Neutrons US Atomic (high -LET)Radiation Workers
Q>1 Gamma 62%
Q=1 1 38%
X-Ray
1
Electron
1 Aircrew
20
TEPC Data from Selected Flight Routes Global Flight Group
Trans-Pacific (CYVR-KIX) Trans-Atlantic (CYYZ-LHR) Trans-Canada (CYYZ-CYVR) Caribbean (BGI-CYYZ) Northwest/Yukon (CYOW-CYFB CYRB-CYSR-CYFB-CYOW)
Flight Time (h)
Total Dose Eq. (μSv)
Q
10.2 6.5 5.0 5.7 10.2
57 ± 9 39 ± 6 35 ± 5 27 ± 4 54 ± 28
2.2 ± 0.4 2.5 ± 0.4 2.4 ± 0.4 2.2 ± 0.4 3.4 ± 0.6
Data Coverage
LP PD DIAP
HNL
PGUA
TEPC Count Rate 40000 35000
2000
30000 25000
1500
20000
Constant Latitude
1000
15000 10000
500
Heading North
5000 0
0 0:00
1:00
2:00
3:00
4:00
Time (Z)
5:00
6:00
7:00
19:00
20:00
21:00
22:00
23:00
Time (Z)
0:00
1:00
2:00
Altitude (ft)
C o u n t R a te (C o u n ts/M in )
2500
YGK-YYZ-HGK Polar Flight (2005) Toronto to Hong Kong
Hong Kong to Toronto 12000
IC+SWENDI HAWK FH41B LiuLin FH41B Corrected Flight Altitude
10000
8000
1
6000
4000
2000
0.1
0
4/18/05 9:00
4/18/05 21:00
4/19/05 9:00
4/19/05 21:00
4/20/05 9:00
4/20/05 21:00
Date and Time
YGK-YYZ YYZ-HGK (polar)
HGK
HGK-YYZ
YYZ-YGK
Altitude (m)
Ambient Dose Equivalent Rate (uSv/h)
10
TEPC Data Analysis
.
Ambient Total Dose Equivalent Rate, H (μSv/h)
Geomagnetic latitude calculated from geographic latitude & longitude 16 9.4 km 10.0 km (+2 μSv/h) 10.6 km (+4 μSv/h) 11.2 km (+6 μSv/h) 11.8 km (+8 μSv/h) Best Fit at 10.6 km
14 12 10 8 6 4 2 0 -45
-30
-15
0
15
30
45
Geomagnetic Latitude, Bm (deg)
60
75
90
Latitude Dependence: Dose Rate Vs Cutoff Rigidity GCR ability to penetrate magnetic field
Ambient Dose Equivalent Rate (μSv/h)
Ambient dose equivalent rate (35000 ft) 10
North South Best Fit
8
6
Global Cutoff Rigidity Contours
.
4
2
0 0
2
4
6
8
10
12
14
Cutoff Rigidity, Rc (GV)
16
18
Altitude Effect (Balloon Flights) 40 km
10
Balloon
10 km
Supersonic
Atmospheric Nucleus
1
fAlt
20 km
Balloon Data (July 14, 2001) Balloon Data (July 23, 2001) Model
Satellite
Subsonic
0.1 1 km
High Peaks
0.01 0
200
400
600
800
Atmospheric Depth h (g / cm2)
1000
Solar Cycle Effect (10.7 km) Ambient dose equivalent rate (μSv/h) normalized to 10.6 km
8 RMC IC+SWENDI (Climax = 3744 counts/h/100, Φ = 984 MV) ACREM IC+NMX (Climax = 4277 counts/h/100, Φ = 498 MV) Best Fit ACREM IC+NMX Best Fit RMC IC+SWENDI
6
4
2
IC + SWENDI 0 0
2
4
6
8
10
12
14
16
18
Vertical cutoff rigidity Rc (MV)
Poles
Equator
PCAIRE Code
Visual_PCAIRE.exe
PCAIRE Code vs Concorde/ER-2 (NASA) (High-Altitude) TEPC Measured Route Dose (uSv)
160 Heliocentric Potential (FAA) Deceleration Parameter (NASA)
140 120
ER-2 North 1
ER-2 North 2
100 ER-2 East 80 60 ER-2 South 1 & 2
40
15.2 -18 km (Concorde) 15.2 - 21 km (ER-2)
Concorde Flights
20 0 0
20
40
60
80
100
120
PCAIRE Predicted Route Dose (μSv)
140
160
Aircrew Annual Exposure PC-AIRE Prediction of Annual Dose Equivalent (mSv)
6 5 4 3 2
ICRP 60 Public Limit
1 0
Flight Attendants
Pilots
Canadian Annual Occupational Exposures 99-EHD-239
A verage Exposure (m Sv/year)
6
Nuclear Fuel Handler Industrial Radiographer Uranium Miner
4
Nuclear Medicine Technologist Commercial Aircrew
2
0
Occupation
Health Impact • ~25% of population will develop fatal cancer • If aircrew exposed to 6 mSv/y over 30 years, risk of developing a fatal cancer: 6 mSv/y x 30 y x 4 x10-5 cancers/mSv = 0.7%
Radiation Exposure from Solar Particle Events (SPE) • Highly sporadic events associated with solar flares and coronal mass ejection – Additional exposure to aircrew
Aircrew Exposure from SPEs
Proton Flux (n/MeV/sr/cm2)
• Propagate GCR and GOES-11 spectra (p, He) through atmosphere with Monte Carlo Code (MCNPX)
SPE GCR
Proton energy (MeV)
Dose and NM Count Rate Prediction Dose Conversion Coefficient
Dose Rate
Primary GOES spectrum
m n m &E, H& (Sv h −1 ) = ∑ ⎡⎢∑ ⎧⎨c ⋅ ΔE ⋅ K ⋅ P ⋅ ⎛⎜ 3600 s ⎞⎟⎫⎬Φ& prim ⎤⎥ = ∑ P (E )Φ& prim (E ) i ,i +1 j ij E ,Ω i i A i E ,Ω ⎝ h ⎠⎭ i =1 ⎣ j =1 ⎩ ⎦ i =1 m ⎡ n ⎧ ⎛ 3600s ⎞⎫ & prim ⎤ m prim −1 & C (count h ) = ∑ ⎢∑ ⎨c ⋅ ΔEi ,i +1 ⋅ R j ⋅ Pij ⋅ ⎜ ⎟⎬ΦE ,Ω i ⎥ = ∑ PNM (Ei )Φ& E ,Ω (Ei ) ⎝ h ⎠⎭ i =1 ⎣ j =1 ⎩ ⎦ i =1
NM Count Rate
Energy bin width
MCNPX matrix coefficients
NM Response Function
Noisy Sun Effects
Global Cutoff Rigidity Contours
Solar Storm Effects and Solar Flare Anisotropy
"SOHO (ESA & NASA)"
Neutron Monitor Analysis th
Neutron monitor peak count rate - April 15 , 2001 1.E+04
RMC Model (3 km)
Count Rate (C/s)
1.E+03
1.E+02
1.E+01
RMC Model (0 km) 1.E+00 100
1000
10000
1.E-01 Effective Cutoff Rigidity (MV)
RMC Model (0 km) Cape Schmidt Irkutsk Jungfraujoch Rome South Pole
Thule Lomniky Stit Alma Ata Kiel Yakutsk
Oulu Magadan Apatity Newark RMC Model (3 km)
SPE Aircrew Exposure (GLE 60) Prague – JFK International, NY 18
(April 2001)
Ambient Dose Rate (μSv/hr)
16 14
Start of Solar Flare
SPE Model
12
Measurements (MDU) 10 8 6 4
GCR (background) (PCAire v7.2)
2 0 10
11
12
13
14
15
16
Universal Time (UTC)
17
18
19
20
* Spurny et al
Commercial Code Development: PCAIRESys •
Operational environment: – Not for Research – Monitoring system for large number of personnel and flights
Airline Airline Human Human resources resources database database
I n t e r f a c e
Database administrator
PCAIRESys
Pcaire system administrator
National Dose Registry
Dose database •dose by flight •dose by crew
Employer
Employees
Sources of Space Radiation (Manned Missions in Low-Earth Orbit)* INNER RADIATION BELT (Protons) SOLAR PARTICLE EVENT (Protons to Iron Nuclei) OUTER RADIATION BELT (Electrons)
N OUTER RADIATION BELT (Electrons)
S
GALACTIC COSMIC RADIATION (GCR) (Protons to Iron Nuclei)
Magnetic Axis
Spin Axis
SOUTH ATLANTIC ANOMALY (Protons)
* Adapted from: M. Golightly, “Radiation Familiarization,” CSA Training with SRAG, NASA, JSC, January 27-31, 2003.
Nominal In-flight Radiation Environment Electrons in outer radiation belt Galactic Cosmic Rays
Protons in South Atlantic Anomaly
Space Weather Radiation Enhancements
Outer electron belt enhancement--electrons Solar particle event (SPE)--protons Additional radiation belts-- high energy electrons, protons (?)
Parameters that Affect Exposure or Susceptibility • Mission Factors • • • • • •
Space Weather Orbit Inclination South Atlantic Anomaly (SAA) Passage Altitude Shielding Length of Mission
• Individual Factors • • • • •
Sex Age Health Status Nutritional Status Ethnicity
Space Radiation Monitoring EV-CPDS: ExtraVehicular Charged Particle Spectrometer
EV-CPDS TEPC PRDs CPDs
IV-CPDS: IntraVehicular Charged Particle Spectrometer TEPC: Tissue Equivalent Proportional Counter RAM: Radiation Area Monitors (TLDs) PRD: Passive Radiation Dosimeter (TLDs) CPD: Crew Passive Dosimeter (TLDs, PNTD) Active instrument real-time telemetry Active instrument no real-time telemetry Passive instrument
IV-CPDS TEPC RAMs CPDs
* Adaped from: M. Golightly, “Initial Briefing to Astronauts Radiation Exposure During Space Missions, 1998 Astronaut Candidate Class,” NASA-JSC, June 10, 1999.
Space Dosimetry* Type
Program
Measurements
Crew Personnel Dosimetry: TLD-100 TLD-300, 600, 700 CR-39 or other Nuclear plastic track detectors Fission Foils
All Programs STS, and ISS Apollo, Skylab, STS, STS, Mir Apollo, STS
Absorbed dose Absorbed dose
STS, Mir, ISS STS, ISS
Absorbed dose Absorbed dose
Apollo, STS Apollo, Skylab STS, Mir, ISS Mir, STS, ISS STS, ISS STS
Fluence vs. LET or Z Neutrons Absorbed dose Lineal energy, dose, dose equivalent Fluence vs. Z and E Neutrons Neutrons
Area dosimetry: TLD-100 TLD-300, 600, 700 CR-39 or other Nuclear plastic track detectors Fission Foils Active Ionization Chambers TEPC Z,E Telescope Bonner Spheres Bubble detectors
Fluence vs. LET or Z Neutrons
*Adapted from: F. Cucinotta, “Organ Dose Estimates for Astronauts,” CSA Training with SRAG, NASA-JSC, January 27-31, 2003.
Typical Exposures •
Daily Exposures – 150 – 200 μGy/d (solar max) (2 x greater at solar minimum) – 25 mGy or ~ 60 mSv for 140 days (CNSC terrestrial limits are 20 mSv/y) – Dependent upon where you spend your time/sleep/timing/altitude etc.
•
SPE Doses (IVA) – Highly variable • Small events ~100– 200 μGy ( ~ 300 μGy @ TEPC/Lab Fwd) • Large events ~ 10 – 20+ mGy (Jul 2000 estimate ~6 mGy @ Node1)
Radiation Exposure Comparisons Type of Exposure
Dose Equivalent
• •
Limit: Annual Canadian Public Limit: Annual Canadian Radiation Worker
• • •
Average annual exposure to natural background Average annual occupational exposure (US) (ground) Living one year in Kerala, India
2.94 mSv/y 2.10 mSv/y 13 mSv/y
•
Airline Flight Crew
1-6 mSv/y
• • • • • • • • •
Apollo 14 Highest Skin Dose Average Shuttle Skin Dose STS 82 Highest Skin Dose STS-57 (473 km, 28.5°) STS-60 (352 km, 57°) 140 day mission on ISS (400 km, 51.56°) 1 year in deep space (5 g cm-2 Al shielding) 1 year deep space (5 g cm-2 polyethylene shielding) Mars mission BFO Dose (GCR+SPE: behind 10 g cm-2 shielding) (3-year)
1 mSv/y 20 mSv/y
14 mSv ~4.33 mSv 76.3 mSv 19.1 mSv 4 mSv ~60 mSv 1140 mSv 870 mSv 800 to 2000 mSv
Biological Effects of Ionizing Radiation •
Ionizing radiation causes atoms and molecules to become ionized or excited: – – – –
•
Produce free radicals Break chemical bonds Produce new chemical bonds and cross-linkage between macromolecules Damage molecules that regulate vital cell processes (e.g. DNA, RNA, proteins).
Tissues that undergo rapid cell regeneration are most sensitive to radiation (e.g., blood-forming organs, reproductive organs, and lymphatic system)
U.S. Astronaut Exposure Limits Non-Stochastic (Deterministic) Effects: NCRP-98 (Sv) and NCRP-132 (Gy-Eq)* Exposure Duration
Blood Forming Organs
Eye
Skin
30 days
0.25
1.0
1.5
Annual
0.50
2.0
3.0
National Council on Radiation Protection and Measurements (NCRP), “Guidance on Radiation Received in Space Activities.” NCRP Report No. 98, (July 31, 1989) NCRP Report No. 132 (Dec 2000)
*NCRP-132 uses relative biological effectiveness (RBE) in place of quality factor (Q)
Career Limit: fatal cancer (3% for all ages and both sexes) Career Exposure Limits NCRP Report No. 98 (1989) (Sv)
10 Year Career Exposure Limits NCRP Report No. 132 (2000) (Sv)
Age (yr)
Male
Female
Male
Female
25
1.5
1.0
0.7
0.4
35
2.5
1.75
1.0
0.6
45
3.25
2.5
1.5
0.9
55
4.0
3.0
3.0
1.7
Observed Astronaut Health Effects (Hamm & Al 2000) •
Significant increase in lifelong risk of cataracts in astronauts • •
•
Of 48 lens opacities in 295 astronauts, 39 of those occurred after space flight 90% of those 39 cataracts occurred after lunar missions and high inclination space flights
14 cases of cancer in 312 astronauts from 1959 to present (excluding nonmelanoma skin cancers) •
59% higher than the control group
Interplanetary Travel • No protection from Earth’s magnetic field
image from NASA/Viking
Summary z
Aircrew Radiation z
PCAIRE Code Development (GCR and Solar Flares) z z
Experimentally-based - Only one! Commercial Airline Application (spin off) (PCAIRESys)
• Space Radiation
Acknowledgements RMC Research Team: Prof. L. Bennett, Research Associates and Assistants (A.R. Green, A. Butler, M. Boudreau, B. Bennett), Graduate Students (Dr. P. Tume, M. McCall, B. Ellaschuck, M. Desormeaux, Dr. M. Pierre, H. Al Anid) Air Canada, Canada 3000 Airlines, Canadian Airlines International, Canadian Regional Airlines, First Air, Aerolinas Argentinas, British Airways, Air Operations at 8 Wing Trenton, 437/436/429 Squadrons J. Servant (Transport Canada),C. Thorp & S. Kupca (DGNS/DND), W. Friedberg (US Federal Aviation Administration), H. Goldberg (Air Transport Association of Canada), M. Pelliccioni & A. Zanini (INFN), E. Felsberger (U Graz), S. Roesler (CERN), A. Chee (Boeing), H.Schraube (GSF), W. Heinrich (U Siegen), K. O’Brien (Northern Arizona U), U. Schrewe (FHH), D. Bartlett (NRPB), V. Ciancio (UNP), D. Irvine (British Airways), J. Lafortune and F. Lemay (PCAIRE Inc) G. Badhwar (NASA-JSC), F. Cuccinotta (NASA-JSC) H. Ing, M. Smith, K. Garrow (Bubble Technology Industries)
