Re: What's a good "proton reflector"?


Old Man wrote:
><mechdan@xxxxxxxxx> wrote in message
>news:1133247545.314604.262590@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

> > http://members.cox.net/mechdan/ppd/index.html

> > The conical "shaped charge" liner implodes, squeezing
> > out hydrogen protons in the process. At the speeds and
> > energies involved here, both the liner and the hydrogen
> > are dense plasmas.

> > My intuitive understanding is that the liner's heavy nuclei
> > will act as proton reflectors

> Do the numbers. Calculate the cross-section for large-angle
> p + Z Coulomb scattering. It's pitifully small. Virtually all
> of your protons will sail through without significant deflection.

I'm sorry, I'm not familiar with the physics calculations for
the cross sections. Is there any material which can act
as a decent "proton reflector"?

I don't understand how the cross section could be so low.
Even without compression, uranium acts as a reasonable
neutron shield. I can't imagine how this can occur other
than by direct collisions between neutrons and uranium nuclei.
I don't understand how a proton could similarly confront a
uranium nuclei on a direct collision path without getting
its path deflected significantly. Even if the deflection for an
individual interaction is only a few degrees, enough
interactions with different nuclei will result in essentially
random brownian motion.

Are you saying that fast protons will simply punch directly
through uranium nuclei, hardly affected at all by either its
electric field or physical collisions? I don't understand
how that could be.

Isaac Kuo

.