RADIATION MONITORING WITH NUCLEAR EMULSIONS ON PROJECT GEMINI. III. THE FLUX OF GALACTIC HEAVY PRIMARIES ON GEMINI VII.
NAVAL AEROSPACE MEDICAL INST PENSACOLA FLA
Pagination or Media Count:
Earlier evaluations of small nuclear emulsion sheets flown on the astronauts bodies during the 14-day Gemini VII mission had been limited to grey tracks which allowed grain counting. This report provides data on the population of heavy tracks. By comparing visual appearance of the diameter of the solid silver core and of the delta ray aura with tracks of known Z, tracks of Z or 20 were identified and counted. A total of 287 such tracks yielded a mission flux of 38.4 nucleisq cm of Z or 20, corresponding to a tissue dose of 1.35 millirads. Theoretical assessment of the flux by considering the geomagnetic latitude profile of the mission leads to 74.8 nucleisq cm of Z or 20. The difference closely matches the expected attenuation due to the inherent shielding of the vehicle and the self-shielding of the astronauts bodies if one assumes a collision mean free path of 14 gsq cm for nuclei of Z or 20. The results confirm earlier estimates that galactic heavy nuclei contribute less than 5 per cent to the total absorbed dose. Author
- Nuclear Instrumentation
- Nuclear Physics and Elementary Particle Physics