Experimental and calculated LET distributions in the Cosmos-2044 biosatellite orbit.

Abstract

During the flight of the Cosmos-2044 biosatellite, joint U.S.S.R.-U.S.A. investigations of different characteristics of cosmic radiation (CR) in the near-Earth environment were carried out. The U.S. dielectric track detectors CR-39 and Soviet BYa- and BR-type nuclear photo-emulsions were used as detectors. The present work shows some results of experimental measurements of linear energy transfer (LET) spectra of CR particles obtained with the use of these detectors, which were placed both inside and outside the satellite. The LET spectra measurement with plastic detectors is composed of two parts: the measurement of galactic cosmic rays (GCR) particles, and of short-range particles. The contributions of these components to the total LET distribution at various thicknesses of the shielding were analyzed and the results of these studies are presented. Calculated LET spectra in the Cosmos-2044 orbit were compared with experimental data. On the basis of experimental and calculated values of the LET spectra, absorbed and equivalent CR doses were calculated. In the shielding range of 1-1.5 g cm-2, outside the spacecraft, the photo-emulsions yielded 10.3 mrad d-1 and 27.5 mrem d-1 (LET > or = 2 MeV cm-1) while the CR-39 yielded averages of 1.43 mrad d-1 and 13.4 mrem d-1 (LET > or = 40 MeV cm-1). Inside the spacecraft (> or = 10 g cm-2) the photo-emulsions yielded 8.9 mrad d-1 and 14.5 mrem d-1.