Numerical calculation of the radiation exposure from galactic cosmic rays at aviation altitudes with the PANDOCA core model

Abstract

The increased radiation exposure at aviation altitudes is of public interest as well as of legal relevance in many countries. The dose rates that are elevated compared to sea level are mainly caused by galactic cosmic ray particles interacting with the atmosphere and producing a complex radiation field at aviation altitudes. The intensity and composition of this radiation field mainly depend on altitude, geomagnetic shielding, and primary particle intensity. In this work, we present a model based on Monte Carlo simulations, which retrospectively estimates secondary particle fluence as well as ambient dose equivalent rates and effective dose rates at any point in the atmosphere. This model will be used as the physical core in the Professional Aviation Dose Calculator (PANDOCA) software developed by the German Aerospace Center (Deutsches Zentrum für Luft-und Raumfahrt) for the calculation of route doses in aviation. The calculations are based on galactic cosmic ray spectra taking into account primary nuclei from hydrogen to iron by direct transport calculations of hydrogen and helium nuclei and approximating heavier nuclei by the number of protons equaling the corresponding atomic number. A comparison to experimental data recorded on several flights with a tissue equivalent proportional counter shows a very good agreement between model calculations and measurements.

Numerical model for computation of effective and ambient dose equivalent at flight altitudes

“…Our model also demonstrates good agreement with a recently proposed model for numerical computation of the radiation exposure from GCRs at aviation altitudes (Matthiä et al 2014). Both models demonstrate good agreement with experimental/reference data, although the calculations slightly overestimate the measurements in the polar region, which are mostly due to modulation/GCR model effects.…”

CONCORD: comparison of cosmic radiation detectors in the radiation field at aviation altitudes

“…PANDOCA, SIEVERT, etc. (Clairand et al 2009;Bottollier-Depois et al 2012;Matthiä et al 2014). Furthermore, most models also permit to assess the dose quantity H*(10) which can be measured, either directly by a Tissue Equivalent Proportional Counter (TEPC) or indirectly by the absorbed dose in silicon with a corresponding conversion factor, determined either in particle accelerator experiments (Mitaroff & Silari 2002) or in the radiation field at flight altitudes (Wissmann et al 2010).…”

RaD‐X: Complementary measurements of dose rates at aviation altitudes

“…The measuring data have been compared with model calculations using the NAIRAS model [ Mertens et al, ] and the PANDOCA model [ Matthiä et al, ]. The results show a good agreement for the dosimetric quantities at the altitudes of commercial aviation (see table ).…”

“…The corresponding values of the W parameter according to Matthiä et al [] are W = 73.6 and W = 70.1. From numerical calculations the difference in dose rates in the target areas from changes in the solar modulation between the 2 days is estimated to be less than 2% and is considered negligible [ Matthiä et al, ].…”

“…Information on measured dose rates at high altitudes, i.e., low atmospheric shielding, is important for the understanding and modeling of the radiation transport through the atmosphere and the development of the secondary radiation field at aviation altitudes. Furthermore, it is indispensable to measure the dose rates at altitudes of commercial aviation in order to validate numerical models for the assessment of occupational radiation exposure of aircrew [ Bottollier‐Depois et al, ], such as PANDOCA [ Matthiä et al, ] and NAIRAS [ Mertens et al, ], and to identify potential for their improvement. Consequently, a comprehensive study of the development of the radiation field in the atmosphere requires measurements in the stratosphere complemented by corresponding data acquired at aviation altitudes, i.e., under the same space weather conditions and the same geomagnetic shielding.…”