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Author: Hermann J. Schaefer Publisher: ISBN: Category : Galactic cosmic rays Languages : en Pages : 32
Book Description
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 nuclei/sq 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 nuclei/sq 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 g/sq 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).
Author: Hermann J. Schaefer Publisher: ISBN: Category : Galactic cosmic rays Languages : en Pages : 32
Book Description
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 nuclei/sq 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 nuclei/sq 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 g/sq 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).
Author: Hermann J. Schaefer Publisher: ISBN: Category : Project Gemini (U.S.) Languages : en Pages : 28
Book Description
Small nuclear emulsion packs worn by the astronauts at three locations inside their space suits were evaluated by track, grain, and enders count for evaluation of LET spectrum and absorbed dose. By using G.5/K.2 emulsion pairs, a sustained resolution over the entire LET scale of protons from zero to relativistic energies was obtained. It was found that the energy dissipation centers heavily on low energies, with 40 per cent of the absorbed dose due to protons of less than 0.1 g/sq cm residual range. Total proton doses at the six locations (left and right chest, thigh pocket of each astronaut) varied from 159 to 233 millirads. The enders count was found to vary by as much as a factor of 1.35 within the same 1 by 1 1/2-inch film sheet, indicating that the radiation field within the vehicle not only varies over distances comparable to body size, but also reflects local inhomogeneities of shielding conditions on a centimeter and millimeter scale. (Author).
Author: Hermann J. Schaefer Publisher: ISBN: Category : Languages : en Pages : 16
Book Description
On Gemini 4 and 5, small packs of nuclear emulsions combined with other radiation sensors to flat pliable units were worn by the astronauts inside their space suits. Track and grain counting of 200 micra llford G.5 and K.2 emulsion pairs in the packs furnished the particle and energy spectrum of the radiation incident upon the astronaut's body. Evaluation of flux and energy spectrum in terms of millirad dose showed that the bulk of the exposure was due to trapped protons picked up in the South Atlantic Anomaly. The energy spectrum of the proton flux within the ship on the body of the astronaut is a continuum extending from zero to about 300 Mev, with a broad, well -developed maximum in the 30 to 40 Mev region. Because of the large fractional flux of low energy particles, the radiation level sensitively depends on local shield geometry producing variations of dose rate at different locations in the capsule of at least 60 per cent. Representative total doses were 48 millirads on Gemini 4 and 105 millirads on Gemini 5. (Author).
Author: Hermann J. Schaefer Publisher: ISBN: Category : Apollo 7 (Spacecraft). Languages : en Pages : 20
Book Description
On the 10.8-day Apollo VII mission, the radiation exposure of the three astronauts was measured with small nuclear emulsion packs on chest, thigh, and ankle. Track and grain count analysis of the G.5 emulsion on the CSM pilot's chest furnished a dose of 122 millirads. The LET distribution was found to be almost similar to the one recorded on the 14-day Gemini VII mission in line with the fact that the orbital parameters of the two missions were also closely similar. The counts of proton enders in all packs showed a markedly greater uniformity in directional distribution than those on Gemini VII. Presumably, this is caused by the heavier shielding of the Apollo vehicle in connection with the greater freedom of movement of the crew in the larger ship which greatly reduce the influence of self-shielding of the body in the overall shield distribution. (Author).
Author: United States. National Aeronautics and Space Administration Scientific and Technical Information Division Publisher: ISBN: Category : Aeronautics Languages : en Pages : 2300
Author: United States. National Aeronautics and Space Administration. Scientific and Technical Information Division Publisher: ISBN: Category : Aeronautics Languages : en Pages : 2088
Author: Hermann J. Schaefer
Author: Hermann J. Schaefer
Author: Hermann J. Schaefer
Author: Hermann J. Schaefer
Author: Hermann J. Schaefer
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Author: Hermann J. Schaefer
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Author: United States. National Aeronautics and Space Administration Scientific and Technical Information Division
Author: United States. National Aeronautics and Space Administration. Scientific and Technical Information Division