Production of Neutrons by Transport of a GCR Solar Minimum Spectrum through Shielding - Paper 112
- Department of Nuclear Engineering, University of Tennessee, 1004Estabrook Rd, Knoxville, TN, 37996 (United States)
The requirements for radiation instrumentation in space can be quite different from those used for terrestrial applications. For example, most neutron instruments used for dosimetry applications used on Earth are sensitive to fission neutron energies and lower, and as such are only useful for neutron energies below 20 to 50 MeV. In space, neutrons are created by galactic cosmic ray (GCR) and solar energetic particle (SEP) interactions in materials, and as such can attain TeV energies and higher. The purpose of this study is to determine the significance of the flux of high energy neutrons in space, and to what degree neutron instruments in space must be sensitive to those high energy neutrons. PHITS transport code calculations of secondary neutron production through various thicknesses of aluminum and water shielding indicate that a significant fraction of the neutron flux and neutron effective dose comes from neutrons above 20 MeV. Measurement of high energy neutrons in space is a difficult task, especially given that the measurement will take place in a mixed radiation field where any signal from an incident neutron must be separated from signals generated by gamma rays, electrons and charged hadrons. Conventional neutron detection methodology dictates that the ability to detect high energy neutrons with a sufficient efficiency depends on the mass of the neutron detector, to first order. The more mass a neutron detector has, the higher the probability of detecting a high energy neutron. However, adding mass comes at a premium in space, often adding costs that prohibit the implementation of a new design with more mass. Thus, to accurately measure the effective dose to humans in space from secondary neutron irradiation, it requires novel methodologies that can stretch the limits of low-mass neutrons detectors, such as developing versatile response functions that are well characterized and can function over a wide range of very different neutron energy spectra. (authors)
- Research Organization:
- American Nuclear Society - ANS, 555 North Kensington Avenue, La Grange Park, IL 60526 (United States)
- OSTI ID:
- 23082932
- Resource Relation:
- Conference: RPSD 2014: 18. Topical Meeting of the Radiation Protection and Shielding Division of ANS, Knoxville, TN (United States), 14-18 Sep 2014; Other Information: Country of input: France; 3 refs.; available on CD Rom from American Nuclear Society - ANS, 555 North Kensington Avenue, La Grange Park, IL 60526 (US)
- Country of Publication:
- United States
- Language:
- English
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