Aircrew and Spacecrew Radiation Exposure - media.cns-snc.ca

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
Aircrew Radiation Exposure Assessment
Measurements and Computer Code Development
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

• European Union
Aircrew Radiation Regulation
(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 (

Epidemiological Studies
• P. Band et al., B.C. Cancer Foundation (Cdn/AC Pilots, 1950-1992)
– Excess AML and prostatic cancer
• J. Grayson et al., Brooks AFB (USAF Pilots, 1975-1989)
– Excess cancer in all sites, testis & urinary bladder
• E. Pukkala et al, Finnish Cancer Registry (FAs, 1967-1992)
– Excess female breast and bone cancer
• European Study of Cancer Among flying PErsonnel (ESCAPE) (9 countries) (1960-1997)
– Scarce evidence for specific occupational cancer risk
– Revised interest with ESCAPE II (or COSMIC) study to include US PAN AM cohort
• D. Irvine, British Airways Pilots, 1998
• B. Grajewski, NIOSH Studies (FA (1998-2000), Pilots (2001))
– FAs reproductive health effects
– Biomarker study of pilots

Radiation Exposure to Aircrew
Galactic Cosmic Rays
(GCR)
Complex mixed-radiation field
Solar Particle Events
(SPE)

Galactic Cosmic Ray (GCR) Exposure Conditions
• Relatively constant field dependent upon:
• Solar Activity
• Latitude
• Altitude
• Complicated field
• Many particle types, large energy range
• Greater uncertainty in biological risk

Solar Magnetic Field Shielding
(When)
• GCR intensity anticoincident with solar cycle
Sunspot Number
400
350
300
250
200
150
100
50
0
19 20 21 22 23
1953 1958 1963 1968 1973 1978 1983 1988 1993 1998 2003 2008
Year
4500
4000
3500
3000
2500
2000
1500
Climax Hourly Count Rate /100

Earth Magnetic Field Shielding
(Where)
• Greater shielding at equator than
geomagnetic poles (factor of ~3)

40 km
20 km
10 km
1 km
Atmospheric Shielding
(How High)
Satellite
Balloon
Supersonic
Subsonic
High Peaks
Atmospheric
Nucleus

Equipment Suite Development
Anthropomorphic Phantom
with TLDs and BDs
MNS
NE213 Scintillator
LET Chamber
LLRM
Detector NIMs, Computers, UPS
BGO
Scintillators

Commercial Aircraft Measurement
Eberline
NRD
SWENDI Ionization
Chamber
TEPC SWENDI

Aircrew Radiation Studies
Experimentation
• ~250 Flights (Portable Instruments)
• Ionization Counter/Al 2O 3 TLDs (low-LET)
• SWENDI Remmeter/Bubble Detectors (high-LET)
• Liulin-4N and 4SN (Si-based) LET Spectrometers
• Tissue Equivalent Proportional Counter (Hawk TEPC)
Model/Code Development
• Predictive Code AIrcrew Radiation Exposure (PCAIRE)

Ambient Dose Equivalent Distribution (μSv)
60
40
20
0
TEPC IC TLD SWENDI BD
TOTAL = IONIZING + NEUTRON

Quality Factor
Q>1
Q=20
Lung
4%
Ionizing
(low-LET) (low LET)
Other
3%
Q=1
Q>1
Gamma
62%
X-Ray Ray
Q=1
38%
1
1
93% Electron
1
Neutrons
(high-LET) (high US Atomic LET) Radiation Workers
Aircrew
20

TEPC Data from Selected Flight Routes
Global Flight Group Flight
Time (h)
Trans-Pacific (CYVR-KIX)
Trans-Atlantic (CYYZ-LHR)
Trans-Canada (CYYZ-CYVR)
Caribbean (BGI-CYYZ)
Northwest/Yukon (CYOW-CYFB
CYRB-CYSR-CYFB-CYOW)
10.2
6.5
5.0
5.7
10.2
Total Dose
Eq. (μSv)
57 ± 9
39 ± 6
35 ± 5
27 ± 4
54 ± 28
Q
2.2 ± 0.4
2.5 ± 0.4
2.4 ± 0.4
2.2 ± 0.4
3.4 ± 0.6

HNL
Data Coverage
LP PD
DIAP
PGUA

Count Rate (Counts/M in)
2500
2000
1500
1000
500
0
TEPC Count Rate
Constant Latitude
0:00 1:00 2:00 3:00 4:00 5:00 6:00 7:00
Time (Z)
Heading North
19:00 20:00 21:00 22:00 23:00 0:00 1:00 2:00
Time (Z)
40000
35000
30000
25000
20000
15000
10000
5000
0
Altitude (ft)

Ambient Dose Equivalent Rate (uSv/h)
10
0.1
1
YGK-YYZ-HGK Polar Flight (2005)
Toronto to Hong Kong Hong Kong to Toronto
IC+SWENDI
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
HAWK
FH41B
LiuLin
FH41B Corrected
Flight Altitude
Date and Time
YGK-YYZ YYZ-HGK (polar) HGK HGK-YYZ YYZ-YGK
12000
10000
8000
6000
4000
2000
0
Altitude (m)

TEPC Data Analysis
Geomagnetic latitude calculated from geographic latitude & longitude longitude
Ambient Total Dose Equivalent Rate, H (μSv/h)
.
16
14
12
10
8
6
4
2
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
0
-45 -30 -15 0 15 30 45 60 75 90
Geomagnetic Latitude, B m (deg)

Ambient Dose Equivalent Rate (μSv/h)
Latitude Dependence:
Dose Rate Vs Cutoff Rigidity
Ambient dose equivalent rate (35000 ft)
.
10
8
6
4
2
0
0 2 4 6 8 10 12 14 16 18
Cutoff Rigidity, Rc (GV)
North
South
Best Fit
GCR ability to penetrate magnetic
field
Global
Cutoff
Rigidity
Contours

40 km
20 km
10 km
1 km
Altitude Effect (Balloon Flights)
Satellite
Balloon
Supersonic
Subsonic
High Peaks
Atmospheric
Nucleus
fAlt
10
1
0.1
0.01
Balloon Data (July 14, 2001)
Balloon Data (July 23, 2001)
Model
0 200 400 600 800 1000
Atmospheric Depth h (g / cm 2 )

Ambient dose equivalent rate (μSv/h)
normalized to 10.6 km
Poles
8
6
4
2
0
Solar Cycle Effect (10.7 km)
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
IC + SWENDI
0 2 4 6 8 10 12 14 16 18
Vertical cutoff rigidity Rc (MV)
Equator

PCAIRE Code
Visual_PCAIRE.exe

PCAIRE Code vs Concorde/ER-2 (NASA)
(High-Altitude)
TEPC Measured Route Dose (uSv)
160
140
120
100
80
60
40
20
0
Heliocentric Potential (FAA)
Deceleration Parameter (NASA)
ER-2 North 2
Concorde Flights
ER-2 South 1 & 2
ER-2 East
ER-2 North 1
15.2 -18 km (Concorde)
15.2 - 21 km (ER-2)
0 20 40 60 80 100 120 140 160
PCAIRE Predicted Route Dose (μSv)

PC-AIRE Prediction of Annual
Dose Equivalent (mSv)
6
5
4
3
2
1
0
Aircrew Annual Exposure
ICRP 60 Public Limit
Flight Attendants Pilots

Canadian Annual Occupational Exposures
Average Exposure
(mSv/year)
6
4
2
0
99-EHD-239
Occupation
Nuclear Fuel
Handler
Industrial
Radiographer
Uranium Miner
Nuclear Medicine
Technologist
Commercial
Aircrew

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
• Propagate GCR and GOES-11 spectra (p, He) through
atmosphere with Monte Carlo Code (MCNPX)
Proton Flux (n/MeV/sr/cm 2 )
GCR
Proton energy (MeV)
SPE

Dose Rate
E&
, H&
Dose and NM Count Rate Prediction
( Sv
C&
( count
h
h
NM Count Rate
−1
−1
) =
) =
m
⎡
∑∑ ⎢
⎣
i=
1 j=
1
m
⎡
∑∑ ⎢
⎣
n
n
i=
1 j=
1
⎧
⎨c
⋅ΔE
⎩
⎧
⎨c
⋅ΔE
⎩
Energy bin width
Global Cutoff
Rigidity
Contours
Dose Conversion
Coefficient
i,
i+
1
i,
i+
1
⋅ K
⋅ R
j
j
⎛ 3600s
⎞⎫
⋅ Pij
⋅⎜
⎟⎬Φ&
⎝ h ⎠⎭
⋅ P
ij
⎛ 3600s
⎞⎫
⋅⎜
⎟⎬Φ&
⎝ h ⎠⎭
NM Response Function
prim
E,
Ωi
prim
E,
Ωi
⎤
⎥ =
⎦
⎤
⎥ =
⎦
m
∑
i=
1
m
∑
i=
1
MCNPX matrix coefficients
Primary GOES
spectrum
P
P
A
NM
Noisy Sun Effects
prim ( E ) Φ&
( E )
i
E,
Ω
prim ( E ) Φ&
( E )
i
E,
Ω
i
i

Solar Storm Effects and Solar Flare Anisotropy
"SOHO (ESA & NASA)"

Count Rate (C/s)
Neutron Monitor Analysis
1.E+04
1.E+03
1.E+02
1.E+01
1.E-01
Neutron monitor peak count rate - April 15 th , 2001
RMC Model (3 km)
RMC Model (0 km)
1.E+00
100 1000 10000
Effective Cutoff Rigidity (MV)
RMC Model (0 km) Thule Oulu
Cape Schmidt Lomniky Stit Magadan
Irkutsk Alma Ata Apatity
Jungfraujoch Kiel Newark
Rome Yakutsk RMC Model (3 km)
South Pole

Ambient Dose Rate (μSv/hr)
18
16
14
12
10
8
6
4
2
SPE Aircrew Exposure (GLE 60)
Prague – JFK International, NY
Start of Solar Flare
GCR (background)
(PCAire v7.2)
(April 2001)
SPE Model
Measurements (MDU)
0
10 11 12 13 14 15 16 17 18 19 20
Universal Time (UTC) * 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
PCAIRESys
Pcaire
system
administrator
Dose database
•dose by flight
•dose by crew
National Dose Registry
Employer
Employees

OUTER RADIATION BELT
(Electrons)
GALACTIC COSMIC RADIATION (GCR)
(Protons to Iron Nuclei)
Sources of Space Radiation
(Manned Missions in Low-Earth Orbit)*
INNER RADIATION BELT
(Protons)
SOLAR PARTICLE EVENT
(Protons to Iron Nuclei)
N
Magnetic
Axis
S
Spin
Axis
OUTER RADIATION BELT
(Electrons)
SOUTH ATLANTIC ANOMALY
(Protons)
* Adapted from: M. Golightly, “Radiation Familiarization,” CSA Training with SRAG, NASA, JSC, January 27-31, 2003.

Protons in South
Atlantic Anomaly
Nominal In-flight Radiation Environment
Electrons in outer radiation belt
Galactic Cosmic Rays

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

EV-CPDS: Extra-
Vehicular Charged
Particle Spectrometer
IV-CPDS: Intra-
Vehicular 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
Space Radiation Monitoring
EV-CPDS
IV-CPDS
TEPC
RAMs
CPDs
TEPC
PRDs
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 All Programs Absorbed dose
TLD-300, 600, 700 STS, and ISS Absorbed dose
CR-39 or other Nuclear plastic Apollo, Skylab, STS, STS,
track detectors
Mir Fluence vs. LET or Z
Fission Foils Apollo, STS Neutrons
Area dosimetry:
TLD-100 STS, Mir, ISS Absorbed dose
TLD-300, 600, 700 STS, ISS Absorbed dose
CR-39 or other Nuclear plastic
track detectors Fluence vs. LET or Z
Fission Foils Apollo, STS Neutrons
Active Ionization Chambers Apollo, Skylab Absorbed dose
TEPC STS, Mir, ISS Lineal energy, dose, dose equivalent
Z,E Telescope Mir, STS, ISS Fluence vs. Z and E
Bonner Spheres STS, ISS Neutrons
Bubble detectors STS Neutrons
*Adapted from: F. Cucinotta, “Organ Dose Estimates for Astronauts,” CSA Training with SRAG, NASA-JSC, January 27-31, 2003.

• Daily Exposures
Typical 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
• 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
• Airline Flight Crew
• 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)
Dose Equivalent
1 mSv/y
20 mSv/y
2.94 mSv/y
2.10 mSv/y
13 mSv/y
1-6 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)

Exposure
Duration
U.S. Astronaut Exposure Limits
Non-Stochastic (Deterministic) Effects: NCRP-98 (Sv) and NCRP-132 (Gy-Eq)*
Blood Forming
Organs Eye Skin
30 days 0.25 1.0 1.5
Annual 0.50 2.0 3.0
*NCRP-132 uses relative biological effectiveness (RBE) in place of quality factor (Q)
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)
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

• No protection from
Earth’s magnetic field
Interplanetary Travel
image from NASA/Viking

Aircrew Radiation
Summary
PCAIRE Code Development (GCR and Solar Flares)
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)