Cosmic Radiation

--- In spacesettlers@yahoogroups.com, "Arthur P. Smith"
wrote:
> victoriatangoman wrote:
>
> >--- In spacesettlers@yahoogroups.com, Andy Goddard

> >wrote:
> >
> >>Oops...belay my last comment...my early morning tea has just
> >>
> >>
> >kicked in. [...]
> >
> >Don't be so quick to belay that comment. [...]
> >
> >Then it occured to me that this "Earth blocking" feature
presupposes
> >that the Earth's atmosphere on the other side of the world
doesn't
> >exist.
> >
> Actually, it's even better than that - radiation blocking works in
an
> exponential manner (there's some distance through the material
that cuts
> the radiation in half, twice that distance cuts it by 4, 3 times
by 8,
> etc. - "half-length" instead of "half-life") so all you need is an
> additional half-length of material to cut the radiation by another
> factor of two. A factor of 2 is not a big deal for this.
>
> Arthur

Thanks for the clarification. Not being a scientist I fuddled my way
through the reasoning here in an attmept to find how the Denver
radiation quote was derived in the original studies and why I see a
figure of 2 meters of regolith quoted extensively as being adequate
radiation shielding.

Using the Al Globus approach yields a shiedling requirement far
exceeding everything I've read about.

Did the original and subsequent researchers overlook the Earth
blocking feature?

Is the mass of the Earth even necessary or does the atmosphere do
the bulk of the job? How do we resolve the two conflicting shielding
requirements from this debate?

TangoMan