Well last night I looked into four of my books on planetary science which I had thought were less likely to contain info than books on space exploration and started getting confused again. Several mentioned that Cosmic Rays are stopped by the magnetic field or a meter of rock (mentioned in Meteorite age measurement methods). Once Again GB provided some good links to help clear things up.

I think http://spacescience.spaceref.com/newhome/headlines/ast17dec99_1.htm contains the best summary related to the questions that have been raised here. I shortened the link to delete the redirect in GB's post to make it easier to copy & paste for Raoul. The magnetosphere does shield a lot of lower energy cosmic rays except at the polls and the atmosphere stops the rest.

Unless people working at the poles are known to have a high radiation it would seem the atmosphere alone is capable of stopping most cosmic rays. This is supported by the meter of rock statement because the column of air above Earth at sea level is equivelent in mass to roughly 3 meters of rock.

shows a table similar to the one in Stine's book showing how much higher energy Cosmic Ray particles are than the ones in the solar wind/flares. One of my books mentioned that Cosmic rays go up to 1000 MeV in energy. I thought those were the most common with energies dropping to a minimum of 100 MeV based on text, but I'm not sure after seeing this table list only the lower end.

Regards,
Mark