Influence of Aircraft Self-Shielding on World-Wide Calculations of Effective Dose Rates to Occupants

Date

2018-07-08

Journal Title

Journal ISSN

Volume Title

Publisher

48th International Conference on Environmental Systems

Abstract

It is commonplace when calculating ionizing radiation exposures of aircraft occupants to neglect the influence of the aircraft’s presence on the dose rate, which greatly simplifies calculations of dose rate. FAA technical report DOT/FAA/AM-17/8 describes a method of revising CARI-7 calculations to approximately account for aircraft structure when calculating effective dose rates based on the NASA Langley Research Center OLTARIS toolset, which yields results consistent with findings of earlier researchers, but without the need for detailed aircraft structure and loading models. The method is applied here to investigate the reasonableness of the common simplification on a global scale at typical flight levels from 30,000 to 40,000 feet, using effective vertical cutoff rigidity world-grids calculated by Smart and Shea. Shielded occupant dose rate is consistently reduced relative to the unshielded case, but the reduction in dose rate at cruise altitude is typically only a few percent at the levels of shielding considered (up to 1.27 cm Al-2024). Results thus indicate that the practice of ignoring this source of occupant shielding does not lead to large errors in effective dose rate calculations for flights in the altitude range examined. Effective doses for both solar minimum and solar maximum are discussed for a number of flight paths (routes) including several polar routes.

Description

Kyle Copeland, Federal Aviation Administration
William Atwell, The Boeing Company
ICES503: Radiation Issues for Space Flight
The 48th International Conference on Environmental Systems was held in Albuquerque, New Mexico, USA on 08 July 2018 through 12 July 2018.

Keywords

Aviation radiation exposures, Atmospheric radiation, FAA CARI-7 calculations

Citation