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Measurements on the shuttle of the LET spectra of galactic cosmic radiation and comparison with the radiation transport modelA new class of tissue-equivalent proportional counters has been flown on two space shuttle flights. These detectors and their associated electronics cover a lineal energy range from 0.4 to 1250 keV/microns with a multichannel analyzer resolution of 0.1 keV/microns from 0.4 to 20 keV/microns and 5 keV/microns from 20 to 1250 keV/microns. These detectors provide the most complete dynamic range and highest resolution of any technique currently in use. On one mission, one detector was mounted in the Shuttle payload bay and another older model in the mid-deck, thus providing information on the depth dependence of the lineal energy spectrum. A detailed comparison of the observed lineal energy and calculated LET spectra for galactic cosmic radiation shows that, although the radiation transport models provide a rather accurate description of the dose (+/- 15%) and equivalent dose (+/- 15%), the calculations significantly underestimate the frequency of events below about 100 keV/microns. This difference cannot be explained by the inclusion of the contribution of splash protons. The contribution of the secondary pions, kaons and electrons produced in the Shuttle shielding, if included in the radiation transport model, may explain these differences. There are also significant differences between the model predictions and observations above 140 keV/microns, particularly for 28.5 degrees inclination orbit.
Document ID
20050000305
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Badhwar, G. D.
(NASA Johnson Space Center Houston, TX United States)
Cucinotta, F. A.
Braby, L. A.
Konradi, A.
Wilson, J. W.
Date Acquired
August 22, 2013
Publication Date
September 1, 1994
Publication Information
Publication: Radiation research
Volume: 139
Issue: 3
ISSN: 0033-7587
Subject Category
Aerospace Medicine
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Radiation Health
STS-51 Shuttle Project
manned
short duration
STS-56 Shuttle Project
NASA Center JSC
Flight Experiment

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