AIR CREW DOSIMETRY WITH EPCARD G. Peter Leuthold and Hans Schraube GSF - National Research Center, Neuherberg - Germany

Transcription

1 QUADOS AIR CREW DOSIMETRY WITH EPCARD G. Peter Leuthold and Hans Schraube GSF - National Research Center, Neuherberg - Germany Physical arameters Dosimetric considerations Princile and rogram structure Data reduction Administrative and layout considerations Exerimental verification and route doses Worksho INTERCOMPARISON ON THE USAGE OF COMPUTATIONAL CODES IN RADIATION DOSIMETRY Bologna, July 14-16, 23 Data required for the calculation of route doses Parameters Determining the Particle Fluence in the Atmoshere: Sectrum of rimary galactic articles x Solar activity (sun sots, 11 res. 22 years modulation) x Shielding of the Earth s magnetic field (cut-off rigidity) Nuclear rocesses in the atmoshere (fragmentation, build-u of secondary articles, absortion) x Atmosheric comonents x variable with time and/or osition Dose calculation along great circle routes between wayoints: Navigation routes (wayoints) Flight rofiles Particle fluence rates for neutrons, rotons, ions, electrons, hotons and muons Conversion factors from fluence to the required dose quantity

2 1E+ 1 Galactic Proton Sectra (data of J.H.Adams, R.Silberberg and C.H.Tsao, 1973) (more recent NASA data are available) rotons (cm² s sr GeV) ¹ -2 1E E E-6 1 solar maximum solar minimum May 1995 Zugsitze (47 N 11 E) cutoff 1E E E+ 1E+1 1E+2 1E+3 kinetic kinetic 1 energy energy E kin kin 1 1 (GeV) (GeV) wk drw Countrate of Climax-neutron monitor and sunsot number sunsot number (lower curve) 3 2 cyle CLIMAX counts (uer curve) year

3 Cosmic radiation in the Earth s atmoshere - Electronhoton comonent e e - n o e - e - e+ e + + n - + e - e +e- o n n n n e - e + n - n n n n Hadron comonent - To of atmoshere + Muon comonent + Sea level Galactic cosmic articles and secondary articles generated in the atmoshere 87% hydrogen, 12% helium, 1% heavy articles The lanetary system is shielded against GCR by the solar field, deending on solar activity and energy of the articles The GCR articles are deflected and artially rejected by the Earth s magnet field (geomagnetic shielding) Particle fluence rates of n, -mesons, hotons, electrons and -mesons increase down to the Pfotzer-maximum, then decrease aroximately with an exonential law (atmosheric shielding) Sectral articles fluence rate at flight altitudes From: W. Heinrich, S. Roesler and H. Schraube Physics of Cosmic Radiation Fields Radiat. Prot. Dosim. 86 (1999)

4 FLUKA-calculated sectral roton fluence rates at different flight conditions From: H. Schraube, W. Heinrich, G. Leuthold and S. Roesler Exerimental and theoretical basis of aviation route dose calculation. Proc. 1th International Congress of the International Radiation Protection Association, Hiroshima, Jaan. T-4-4, P-1a-45 (2) Risk Related Quantity Dosimetric Quantities Effective dose E (ICRP 74, 1996) (EP) Mathematical MIRDhantom (ADAM and EVA) Conversion coefficient: E/ ) Calculation secification for effective dose: E (E/ )

5 Dosimetric Quantities 2. Oerational Quantity (EP) H(1mm) Ambient dose equivalent H*(1) (ICRP 74, 1996) 3cm ICRU shere Conversion coefficient: h* = H*(1)/ Calculation secification for ambient dose equivalent: H * ( 1) (H * / ) 3. Dosemeter Reading (EP) Dose indication: M ~ H*(1) Instrument reading: M (R/ ) 1E-8 Conversion factors for ambient dose equivalent and effective dose for rotons (Ferrari, Pellicioni et al., 1998) 2 H / F (Sv cm2) 2 ) 1E-9 1E-1 1E-11 H*(1) / Eff. dose E / ratio H*(1) / E E / H*(1) 1E-12 1E E E E+ 1 1E E-5 1E-3 1E-1 1E+1 roton energy (GeV) roton energy Er (GeV)

6 Scheme for the calculation of aviation route doses FLUKA Monte-Carlo-Radiation Transort Program (INFN, CERN, SLAC) EPCARD Program Package for the Calculation of Aviation Route Doses transort calculation for: n,,, e+-,, as function of deth in the atmoshere:...1g/cm2 arameters: - solar deceleration otential - cutoff-rigidity data reduction geograhic osition date of flight & Climax monitor flight altitude flight route cutoff-rigidity solares otential deth in atmoshere dose at flight conversion coefficients Data reduction examle: neutrons at 465MV solar dec. otential and GV cutoff 1 3 neutron fluence rate (cm-2 s-1) FLUKA-data fitted curve ercent deviation Neutron fluence rate in the Earth's atmoshere 465 MV / GV 2 1 ercent deviation.1 range of flight levels range of fitted data deth in the atmoshere (g/cm2) ara_art.123 Fig

7 Equivalence of dose determination rocesses Evaluation rocess for individual dosemeters film dosemeter densitometer otical density corrected reading dosemeternumber exosureeriod calibration data hoton dose H energy Evaluation rocess for individuals in an air lane flight flight number date flight route flight rofile EPCARD fluence matrix for all kinds of radiation conversion coefficients electrons hotons muons neutrons rotons dose H* effective dose EPCARD Administrative considerations Develoment on behalf of the Euroean Commission Simle introduction of new conversion factors and resonses Scientific, non-commercial roduct, testversion Should also serve as a tool to combine exerimental data obtained under different conditions Aim: routine calculation in line with Article 42 (EURATOM 96/29) and with subsequent national regulations Layout considerations Simle handling Executable on the lowest level PC and hand-helds Kernel should run also on main frame comuters No external libraries No sohisticated grahic tools, no animation, high seed

8 Exerimental vs calculated neutron doserate near solar maximum 5 5 H*(1) neut from EPCARD ( Sv/h) EPC neut 33 feet EPC neut 35 feet EPC neut 37 feet EPC neut 39 feet EPC neut 41 feet EPCARD/ABH-meter r= Ratio EPCARD / Reading Cutoff rigidity (GV) Left scale: calculated (EPCARD) neutron doserate H*(1) for flight altitudes 33 to 41 ft (closed symbols). Right scale: ratio r of calculated doserate H*(1) to corrected reading of moderator detector with lead converter (oen symbols with 1s-error bars) Doses along flightroutes from MUC / FRA* calculated with EPCARDv Jan 22 flight scheme: 3min asc, FL37, great circle, 3min desc sorted with increasing flight time EPCARD V dose (usv) Brüssel Rom Paris Bukarest effective dose ambient dose equ. flight time London Stockholm Athen Dublin Madrid Ankara Moskau Tel Aviv Kairo Lissabon Las Palmas Kuwait* Abu Dhabi New York Toronto Colombo Peking Washington Chicago Bangkok Shanghai* Seoul* Johannisburg* Vancouver* Atlanta Miami Tokio* Singaur* Cancun San Francisco Sao Paulo Buenos Aires* 1 5 flight time (h)

9 Calculated relative contribution to effective dose from each radiation comonent 1 9 relative dose contribution Abu Dhabi Ankara Athen Atlanta effective dose E 1998 (near solar minumum) flights from MUC/FRA to Bangkok Brüssel Buenos Aires* Bukarest Cancun Chicago Colombo Dublin Johannisburg* Kairo Kuwait* Las Palmas Lissabon London Madrid Miami Moskau New York Paris hotons muons electrons rotons neutrons Peking Rom San Francisco Sao Paulo Seoul* Shanghai* Singaur* Stockholm Tel Aviv Tokio* Toronto Vancouver* Washington Summary EPCARD ermits the calculation of radiation doses on any required route and rofile Data base is the full descrition of the radiation field by the Monte Carlo rogram FLUKA using the most recent NASA model of solar modulation Doses are reorted both in ambient dose equivalent and the nonmeasurable effective dose The contribution of the single article tyes may be reorted searately Any change in radiological estimation (e.g. by radiation weighting factor) may easily be introduced Agreement with measurements is very good if the measured data are corrected for sectral effects of the devices