2. What types of secondary radiation are produced in the CM as it traverses the belts?
Protons, neutrons, electrons, gammas and x-rays, and alpha particles
3. Explain the mechanism for the secondary radiation.
Material shielding can be effective against galactic cosmic rays, but thin shielding may actually make the problem worse for some of the higher energy rays, because more shielding causes an increased amount of secondary radiation. In interplanetary space, however, it is believed that thin aluminium shielding would give a net increase in radiation exposure but would gradually decrease as more shielding is added to capture generated secondary radiation. The main contributions to the radiation doses arise from high-energy heavy ion (HZE) particles. As the incident radiations attenuate in the shield material, there is a significant buildup of secondary particles resulting from nuclear fragmentation and coulomb dissociation processes. A substantial fraction of these secondaries are energetic protons and neutrons. During solar minimum periods, at least 1 g/era 2 of liquid hydrogen shielding, 3.5 g/cm 2 of water shielding, or 6.5 g/cm 2 of aluminum shielding will be needed to keep the estimated risk to the blood-forming organs below the current annual Space Station Freedom limit of 0.5 Sv/year. The preferred materials of choice for galactic cosmic ray shielding are materials with low atomic mass number constituents and significant hydrogen content.
4. How does the material in the hull affect the spectrum of radiation produced.
The heavier the atomic number of the shielding the greater the resultant secondaries
5. Describe the penetration of that secondary radiation through the CM.
Braeunig claims forty percent of the incident proton energy is radiated in the form of secondary particles and electromagnetic radiation. Because these energies are easily absorbed in the body the damage is actually greater from the secondaries tha the primaries.
6. How does the integral flux for electrons > 1 MeV change with energy?
The integral flux decreases as energy increases.
7. The geomagnetic axis and normal to the orbital plane at TLI are inclined to each other. How does this effect the distribution of radiation relative to the orbital plane?
The geomagnetic equator is 11.5 degrees above the geographical equator. This results in a lunar plane of roughly 29 degrees to the equator being 17.5 degrees above the geomagnetic equator.
8. Another question for tim: accepting for the moment Orion and Apollo had the same parking orbit in LEO, and remained have you considered the effect of Orion and Apollo starting their apogee-raising burns at different points in their orbit?
I have repeatedly stated the only contributing factor in radiation exposure other than time is angle or inclinatination of the transit. The steeper the inclination the lower the exposure. The TLI does not change the the orbital plane it only expands the apogee of the orbit. Rockets do not steer with the main engine, they steer with thrusters and unless they did then they would remain on identical orbital planes.
