A NEW SEMI-EMPIRICAL AMBIENT TO EFFECTIVE DOSE CONVERSION MODEL FOR THE PREDICTIVE CODE FOR AIRCREW RADIATION EXPOSURE (PCAIRE)
| Autor: | Brent J. Lewis, M. R. Bean, L. G. I. Bennett, M. J. McCall, T Dumouchel, F. Lemay |
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| Rok vydání: | 2015 |
| Předmět: |
Aircraft
Physics::Medical Physics Monte Carlo method Proportional counter Cosmic ray Radiation Radiation Dosage Effective dose (radiation) Risk Assessment 030218 nuclear medicine & medical imaging Toxicology 03 medical and health sciences 0302 clinical medicine Occupational Exposure Humans Radiology Nuclear Medicine and imaging Solar Activity Radiometry Physics Radiological and Ultrasound Technology Equivalent dose Public Health Environmental and Occupational Health General Medicine Models Theoretical Weighting Computational physics 030220 oncology & carcinogenesis Aircrew Monte Carlo Method Cosmic Radiation |
| Zdroj: | Radiation protection dosimetry. 172(4) |
| ISSN: | 1742-3406 |
| Popis: | The Predictive Code for Aircrew Radiation Exposure (PCAIRE) is a semi-empirical code that estimates both ambient dose equivalent, based on years of on-board measurements, and effective dose to aircrew. Currently, PCAIRE estimates effective dose by converting the ambient dose equivalent to effective dose (E/H) using a model that is based on radiation transport calculations and on the radiation weighting factors recommended in International Commission on Radiological Protection (ICRP) 60. In this study, a new semi-empirical E/H model is proposed to replace the existing transport calculation models. The new model is based on flight data measured using a tissue-equivalent proportional counter (TEPC). The measured flight TEPC data are separated into a low- and a high-lineal-energy spectrum using an amplitude-weighted 137Cs TEPC spectrum. The high-lineal-energy spectrum is determined by subtracting the low-lineal-energy spectrum from the measured flight TEPC spectrum. With knowledge of E/H for the low- and high-lineal-energy spectra, the total E/H is estimated for a given flight altitude and geographic location. The semi-empirical E/H model also uses new radiation weighting factors to align the model with the most recent ICRP 103 recommendations. The ICRP 103-based semi-empirical effective dose model predicts that there is a ∼30 % reduction in dose in comparison with the ICRP 60-based model. Furthermore, the ambient dose equivalent is now a more conservative dose estimate for jet aircraft altitudes in the range of 7-13 km (FL230-430). This new semi-empirical E/H model is validated against E/H predicted from a Monte Carlo N-Particle transport code simulation of cosmic ray propagation through the Earth's atmosphere. Its implementation allows PCAIRE to provide an accurate semi-empirical estimate of the effective dose. |
| Databáze: | OpenAIRE |
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