Calculation of Cosmic Radiation Exposure of Aircrew: PCAIRE Code B.J. Lewis, L.G.I. Bennett with A.R. Green, M.J. McCall, M. Pierre, B. Ellaschuk and A. Butler Royal Military College of Canada Air Crew Radiation Protection Symposium Hannover,, Germany February 28, 2002
Outline Cosmic Radiation Considerations Cosmic Radiation Study PCAIRE Model & Code Demonstration PCAIREsys Development Demonstration
Cosmic Radiation Considerations Relatively constant radiation field : 1 Solar Activity 2 Latitude 3 Altitude Complicated Many particle types, large energy range High quality factor & biological risk Other Radiation measurements +/- 20% Canadian & EU regulations similar
1. Solar Activity Sunspot Number 400 350 300 250 200 150 100 50 450 400 350 300 250 200 Hourly Count Rate/1000 Radiation intensity anticoincident with 11-year solar cycle Difficult to model due to non-uniformity 0 1953 1958 1963 1968 1973 1978 1983 1988 1993 1998 Year 150
2. Latitude Earth s magnetic field Greater shielding at equator than geomagnetic poles (factor of 2-3) 2 Levels off at Geomagnetic Knee, ~50
3. Altitude 40 km 20 km Satellite Balloon Supersonic Atmospheric Nucleus Radiation field is higher at jet altitudes (factor of 100) 10 km Subsonic 1 km High Peaks
Cosmic Radiation Study (1991-2002) Surveys Air Force, 6 Canadian Airlines Neutron Bubble Detector Experimentation 62 Flights (Portable Instruments) Tissue Equivalent Proportional Counter (TEPC) Ionization Counter (low-let)/ LET)/TLDsTLDs + Remmeter/Bubble Detector (high-let) Code Development Predictive Code - Aircrew Radiation Exposure (PC-AIRE)
Equipment Suite Development Anthropomorphic Phantom with TLDs and BDs Detector NIMs, Computers, UPS MNS LET Chamber BGO Scintillators NE213 Scintillator LLRM
Equipment Suite Development
Equipment Suite Development Tissue Equivalent Proportional Counter Bubble Detectors and TLD s under Foam
Dose Equivalent Distribution (µsv( Sv) 60 40 20 0 TEPC IC TLD RM BD TOTAL DE = IONIZING + NEUTRON
Data Coverage LP PD DIAP HNL PGUA
TEPC Count Rate 2500 40000 Count Rate (Counts/Min) 2000 1500 1000 500 Constant Latitude Heading North 35000 30000 25000 20000 15000 10000 5000 Altitude (ft) 0 0:00 1:00 2:00 3:00 4:00 5:00 6:00 7:00 Time (Z) 19:00 20:00 21:00 22:00 23:00 0:00 1:00 2:00 Time (Z) 0
TEPC Data Analysis (36 Flights) Geomagnetic latitude calculated from geographic latitude & 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) Data plotted digitally from equator to poles Affected by difference in geographical & geomagnetic poles
Dose Rate Vs Cutoff Rigidity Dose equivalent rate (35000 ft, 650 MV) GCR ability to penetrate magnetic field Total Dose Equivalent Rate (µsv/h). 10 8 6 4 2 0 0 2 4 6 8 10 12 14 16 18 Cutoff Rigidity, Rc (GV) North South Best Fit Global Cutoff Rigidity Contours - Better way of digitally plotting data & thus providing a function
Solar Cycle Effects Normalized Ambient Total Dose Equivalent Rate, (µsv h -1 ) 10 8 6 4 2 0 f 2 RMC Data (U = 650 MV, φ = 650 MV) Best Fit (Sigmoid) (f 1 ) RMC Data (U = 870 MV, φ = 1160 MV) Best Fit (Sigmoid) (f 2 ) 0 2 4 6 8 10 12 14 16 18 Vertical Cutoff Rigidity (IGRF 1995), R c (GV) f 1 TEPC data for 2 sets of measurements near max & min of solar cycle 2 corresponding functions, f 1 & f 2 adjust for solar cycle Ongoing measurements
Altitude Effects 10 Balloon Data (July 14, 2001) Balloon Data (July 23, 2001) Model Function adjusted for altitude f Alt 1 0.1 (ξ s ) GCR = 0.0068 cm 2 g -1 0.01 0 200 400 600 800 Atmospheric Depth (g cm -2 )
PCAIRE Code Demonstration (Single Entry)
Model and Code Validation PTB Data and LUIN Code 26 Independent TEPC Route Dose Data 10 60 (µsv/h) (Normalized). Dose Rate 8 6 4 2 0 RMC PTB LUIN 2000 0 3 6 9 12 15 18 Measured Route Dose (µsv) 50 40 30 20 10 0 0 10 20 30 40 50 60 Effective Cutoff Rigidity (GV) Predicted Route Dose with PC-AIRE (µsv)
Code Development: PCAIRESys Operational environment: Management 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 Dose database dose by flight dose by crew Crew Crew Crew
PCAIRESys Features Platforms: Standalone application (personal PC/Web access) Kernel incorporated into airline personnel database Data treatment centre Web/LAN batch processing/airline database interface Functionality: Single flight entry or batch file processing Query by flight, crew, occupation or date Great circle route or way points Secure access
PCAIRESys Demonstration (Multiple entry) Create an organization Create an administrator for the organization Enter users Enter one flight by city pair Enter batch flights (show one file that works and modify slightly) Enter batch flight by way point (take a small file) Query By admin for one year By admin for one crew Log out and log on as user, and query by quarter, then year, then n flight
Summary Research over a decade Surveys, Experimentation, Modelling Measurements continuing PCAIRE Code development Experimentally-based (TEPC data) PCAIRE Code PCAIREsys Code for batch aircrew exposure calculation Canadian air force, Canadian-based airlines
Acknowledgements Management, Employees and Unions of Air Canada, Canada 3000 Airlines, Canadian Airlines International, Canadian Regional Airlines & First Air 1 Canadian Air Division, Air Operations at 8 Wing Trenton, 437/436/429 Squadrons J. Servant (Transport( Canada), and C. Thorp and S. Kupca (DGNS/DND) J. Lafortune & F. LeMay (PCAIRE Inc)