Re: Thorium X-Rays from U-238

[Michael McNaughton <mcnaught@LANL.GOV>]

At 11:08 AM 10/21/2004, Peter.Vernig@MED.VA.GOV wrote:

>I don't see why both K and L shell electrons should not be self ionized by 

>alpha particles.



The energy to ionize the L-shell electron comes from the de-excitation of 

the thorium nucleus, not from the alpha particle. The thorium de-excitation 

energy is 50 keV, which is too small to ionize a K-shell electron.



Why doesn't the alpha particle ionize K-shell electrons? In my 

simple-minded model, the alpha particle only interacts with a K-shell 

electron when it is between the K and L shells, which is a fuzzy concept 

and a very short time; anyway, it has a very low probability. For a more 

detailed discussion, see http://prola.aps.org/abstract/PR/v90/i1/p11_1



mike



Mike McNaughton

Los Alamos National Lab.

email: mcnaught@LANL.gov or mcnaughton@LANL.gov

phone: 505-667-6130; page: 505-664-7733



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