[Phys-L] Re: cosmic rays bombarding rocks

[Brian Whatcott <betwys1@SBCGLOBAL.NET>]

At 02:52 PM 9/22/2005, Mike M., you wrote:
> I read in the NY Times a week or so ago about dating method to determine
> approximately the time when glaciers retreated and rocks were uncovered.  The
> method involved, I believe, a beryllium isotope, and had a possible precision
> of plus or minus 500 years.
>
> I have not been able to find that article again, but some web searching
> turned up some pages on 'cosmogenesis'. This involves cosmic rays, mostly
> protons and mu mesons, bombarding silicas in rocks and producing Be-10 and
> also Al-26.  The beryllium-10 half-life is about 2.7 million years, so it
> seems like a suitable vehicle for dating on the order of 10,000 - 20,000
> years.
>
> Does anyone have an inkling of how cosmic ray particles could create
> beryllium 10 from oxygen and silicon?
>
>
> Mike Moloney, Physics & Optical Engineering Department
> Rose-Hulman Inst of Tech, 812 877 8302
> moloney@rose-hulman.edu   http://www.rose-hulman.edu/~moloney


Treat this unresearched speculation with extreme reserve:

30/14 Si acquires a proton & emits an alpha to 26/13 Al
(the alpha accounts for Z-4, A -2;
the proton accounts for A + 1 )

30/14 Si splits directly  to three 10/4 Be with the acquisition
of 2  muon.
(the two muon account for A - 2 )

Then there's the incredible 5 alpha particle route to
  10Be from 30Si....



Brian Whatcott    Altus OK    Eureka!
_______________________________________________
Phys-L mailing list
Phys-L@electron.physics.buffalo.edu
https://www.physics.buffalo.edu/mailman/listinfo/phys-l