Title :
The low Earth orbit radiation environment and its evolution from measurements using the CREAM and CREDO experiments
Author :
Dyer, C.S. ; Sims, A.J. ; Truscott, P.R. ; Farren, J. ; Underwood, C.
Author_Institution :
Defense Res. Agency, Farnborough, UK
fDate :
12/1/1993 12:00:00 AM
Abstract :
The new regime of trapped protons centered around L=2.5 and observed by CRRES (Combined Release and Radiation Effects Satellite) between March and October 1991 has been observed by CREAM (Cosmic Radiation Environment and Activation Monitor) on Shuttle missions at an altitude of 569 km in September 1991 (STS-48) and at altitudes of 385 km and 326 km in December 1992 on STS-53. CREDO (Cosmic Radiation Environment and Dosimetry instrument) on UOSAT-3 at 800 km observed the decay of the belt from March 1991 to March 1992. At high latitudes cosmic-ray fluxes have increases by a factor of two between June 1991 and March 1993. The effect of Shuttle shielding on cosmic rays is to increase the fluxes of low LET (linear energy transfer) secondaries and neutrons. Trapped protons and their dose contribution are attenuated, but again significant fluxes of secondary neutrons are produced
Keywords :
artificial satellites; geophysical aspects of cosmic rays; neutron effects; proton effects; radiation belts; 326 km; 385 km; 569 km; 800 km; CREAM; CREDO; CRRES; Combined Release and Radiation Effects Satellite; Cosmic Radiation Environment and Activation Monitor; Cosmic Radiation Environment and Dosimetry instrument; Shuttle missions; UOSAT-3; cosmic-ray fluxes; effect of Shuttle shielding; low Earth orbit radiation environment; low LET fluxes; secondary neutrons; trapped protons; Belts; Cosmic rays; Dosimetry; Energy exchange; Instruments; Low earth orbit satellites; Neutrons; Protons; Radiation effects; Radiation monitoring;
Journal_Title :
Nuclear Science, IEEE Transactions on
