A comparison of depth dependence of dose and linear energy transfer spectra in aluminum and polyethylene

Citation
Gd. Badhwar et Fa. Cucinotta, A comparison of depth dependence of dose and linear energy transfer spectra in aluminum and polyethylene, RADIAT RES, 153(1), 2000, pp. 1-8
Citations number
19
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Experimental Biology
Journal title
RADIATION RESEARCH
ISSN journal
0033-7587 → ACNP
Volume
153
Issue
1
Year of publication
2000
Pages
1 - 8
Database
ISI
SICI code
0033-7587(200001)153:1<1:ACODDO>2.0.ZU;2-4
Abstract
A set of four tissue-equivalent proportional counters (TEPCs), with their d etector heads at the centers of 0 (bare), 3, 7 and 9-inch-diameter aluminum spheres, were flown on Shuttle flight STS-89, Five such detectors at the c enters of polyethylene spheres were flown 1 year earlier on STS-81, The res ults of dose-depth dependence for the two materials convincingly show the m erits of using material rich in hydrogen to decrease the radiation exposure to the crew. A comparison of the calculated galactic cosmic radiation (GCR ) absorbed dose and dose-equivalent rates using the radiation transport cod e HZETRN with nuclear fragmentation model NUCFRG2 and the measured GCR abso rbed dose rates and dose-equivalent rates shows that they agree within root mean square (rms) error of 12.5 and 8.2%, respectively. However, there are significant depth-dependent differences in the linear energy transfer (LET ) spectra. A comparison for trapped protons using the proton transport code BRYNTRN and the AP-8 MIN trapped-proton model shows a systematic bias, wit h the model underpredicting dose and dose-equivalent rates. These results s how the need for improvements in the radiation transport and/or fragmentati on models. (C) 2000 by Radiation Research Society.