[ExI] Why space tech isn't cutting edge

[spike]

... On Behalf Of Adrian Tymes
Subject: Re: [ExI] Why space tech isn't cutting edge

On Sat, Nov 24, 2012 at 2:56 PM, spike <spike66 at att.net> wrote:


>> ...  Of course with sufficiently thick shielding, you could physically
stop the particle and everything it generates.

>...How thick are we talking, approximately?

Good question.  The atmosphere is equivalent to a little over half a meter
of tungsten, so if that is sufficient, then a spherical shield would have a
mass of about 16 tons.  What do we get?  Another day older and deeper in
debt...


>...  Is it correct to interpret that as, any solid shield less than that
might as well not be there, for the (lack of) protection it provides?

Hmmm, understatement.  A shield might actually be worse than nothing at all,
since it doesn't stop many particles but generates a bunch of new ones in
the collision.

>...  Because if so, then you have to worry about the spall cone that is
generated inside the chip itself - forget about any shielding, if the cosmic
particle itself is not prevented from intersecting the chip...  

Keep in mind that cosmic rays come in all sizes.  So any shielding stops
some particles, and some particles punch right through any shielding.  In
the above example of using 1 atmosphere equivalent shielding, some particles
can punch all the way through the atmosphere.  If you ever get to see a
bubble chamber, there you see particles that penetrated the atmosphere and
the ceiling of whatever building you are in.  Our electronics work anyway,
so there aren't many of them.   But some do make it.

>...Also, is it possible to meaningfully alter the course of the cosmic
particle - say, over the distance of 10 meters, deflect it by millimeters?

Millimeters over 10 meters, I would sure think so.

>...Unless you mean basically a high-speed hydrogen atom (and it seems like
the particles would be moving too fast to bond like that before reaching the
chip), the field can pull the pair apart...

Ja, I don't know all the physics, it has been tragically many years since I
was fooling with this.  A good portion of those particles will be neutrons,
and your magnetic field will be useless against those things.  One of the
many things that can happen when a neutron hits something is that it somehow
creates a proton-electron pair, plus a neutrino to balance the spin and a
photon to balance the energy equation, but what I don't recall is how you
balance if there is a collision involved.  Adrian, you are making me THINK
here.  It's been a while since I worked on this stuff man.  Another unknown
here is I don't recall if the high-energy neutron actually bashes a nucleus
and creates its own bunch of neutrons, like a cue ball smacking into a rack
of billiard balls. 

>>... I hope you come up with a solution to that cosmic ray problem.  We are
cheering wildly for you Adrian.

>...Yeah, well, only if you help.  :P
_______________________________________________

Oy, I could fill a library with what I don't know.  Actually I couldn't:  I
wouldn't know what to put in it.

spike