MEASUREMENTS OF THE LINEAR-ENERGY-TRANSFER SPECTRA ON THE MIR ORBITALSTATION AND COMPARISON WITH RADIATION TRANSPORT MODELS

A tissue equivalent proportional counter designed to measure the linea r energy transfer spectra (LET) in the range 0.2-1250 keV/mu m was flo wn in the Kvant module on the Mir orbital station during September 199 4. The spacecraft was in a 51.65 degrees inclination, elliptical (390 x 402 km) orbit. This is nearly the lower limit of its flight altitude . The total absorbed dose rate measured was 411.3 +/- 4.41 mu Gy/day w ith an average quality factor of 2.44. The galactic cosmic radiation ( GCR) dose rate was 133.6 mu Gy/day with a quality factor of 3.35. The trapped radiation belt dose rate was 277.7 mu Gy/day with an average q uality factor of 1.94. The peak rate through the South Atlantic Anomal y was similar to 12 mu Gy/min and nearly constant from one pass to ano ther. A detailed comparison of the measured LET spectra has been made with radiation transport models. The GCR results are in good agreement with model calculations; however, this is not the case for radiation belt particles and again points to the need for improving the AP8 omni -directional trapped proton models.