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Neutron spectrum and dose-equivalent in shuttle flights during solar maximum

Journal Article:

Abstract

This paper presents unambiguous measurements of the spectrum of neutrons found in spacecraft during spaceflight. The neutron spectrum was measured from thermal energies to about 10 MeV using a completely passive system of metal foils as neutron detectors. These foils were exposed to the neutron flux bare, covered by thermal neutron absorbers (Gd) and inside moderators (Bonner spheres). This set of detectors was flown on three U.S. Space Shuttle flights, STS-28, STS-36 and STS-31, during the solar maximum. We show that the measurements of the radioactivity of these foils lead to a differential neutron energy spectrum in all three flights that can be represented by a power law, J(E){approx equal}E{sup -0.765} neutrons cm{sup -2} day {sup -1} MeV{sup -1}. We also show that the measurements are even better represented by a linear combination of the terrestrial neutron albedo and a spectrum of neutrons locally produced in a aluminium by protons, computed by a previous author. We use both approximations to the neutron spectrum to produce a worst case and most probable case for the neutron spectra and the resulting dose-equivalents, computed using ICRP-51 neutron fluence-dose conversion tables. We compare these to the skin dose-equivalents due to charged particles during the  More>>
Authors:
Keith, J E; Badhwar, G D; Lindstrom, D J [1] 
  1. National Aeronautics and Space Administration, Houston, TX (United States). Lyndon B. Johnson Space Center
Publication Date:
Jan 01, 1992
Product Type:
Journal Article
Reference Number:
AIX-23-035393; EDB-92-082833
Resource Relation:
Journal Name: Nuclear Tracks and Radiation Measurements (International Journal of Radiation Applications and Instrumentation, Part D); (United Kingdom); Journal Volume: 20:1
Subject:
61 RADIATION PROTECTION AND DOSIMETRY; SOLAR ACTIVITY; NEUTRON SPECTRA; SPACE SHUTTLES; RADIATION DOSES; DOSE EQUIVALENTS; AIRCRAFT; DOSES; SPACE VEHICLES; SPECTRA; VEHICLES; 560101* - Biomedical Sciences, Applied Studies- Radiation Effects- Dosimetry & Monitoring- (1992-)
OSTI ID:
5308647
Country of Origin:
United Kingdom
Language:
English
Other Identifying Numbers:
Journal ID: ISSN 0735-245X; CODEN: NTRMD
Submitting Site:
GBN
Size:
Pages: 41-47
Announcement Date:
Jun 01, 1992

Journal Article:

Citation Formats

Keith, J E, Badhwar, G D, and Lindstrom, D J. Neutron spectrum and dose-equivalent in shuttle flights during solar maximum. United Kingdom: N. p., 1992. Web.
Keith, J E, Badhwar, G D, & Lindstrom, D J. Neutron spectrum and dose-equivalent in shuttle flights during solar maximum. United Kingdom.
Keith, J E, Badhwar, G D, and Lindstrom, D J. 1992. "Neutron spectrum and dose-equivalent in shuttle flights during solar maximum." United Kingdom.
@misc{etde_5308647,
title = {Neutron spectrum and dose-equivalent in shuttle flights during solar maximum}
author = {Keith, J E, Badhwar, G D, and Lindstrom, D J}
abstractNote = {This paper presents unambiguous measurements of the spectrum of neutrons found in spacecraft during spaceflight. The neutron spectrum was measured from thermal energies to about 10 MeV using a completely passive system of metal foils as neutron detectors. These foils were exposed to the neutron flux bare, covered by thermal neutron absorbers (Gd) and inside moderators (Bonner spheres). This set of detectors was flown on three U.S. Space Shuttle flights, STS-28, STS-36 and STS-31, during the solar maximum. We show that the measurements of the radioactivity of these foils lead to a differential neutron energy spectrum in all three flights that can be represented by a power law, J(E){approx equal}E{sup -0.765} neutrons cm{sup -2} day {sup -1} MeV{sup -1}. We also show that the measurements are even better represented by a linear combination of the terrestrial neutron albedo and a spectrum of neutrons locally produced in a aluminium by protons, computed by a previous author. We use both approximations to the neutron spectrum to produce a worst case and most probable case for the neutron spectra and the resulting dose-equivalents, computed using ICRP-51 neutron fluence-dose conversion tables. We compare these to the skin dose-equivalents due to charged particles during the same flights. (author).}
journal = {Nuclear Tracks and Radiation Measurements (International Journal of Radiation Applications and Instrumentation, Part D); (United Kingdom)}
volume = {20:1}
journal type = {AC}
place = {United Kingdom}
year = {1992}
month = {Jan}
}