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From: ethan@utastro.UUCP (Ethan Vishniac)
Newsgroups: net.physics
Subject: decay rates and temperature
Message-ID: <78@utastro.UUCP>
Date: Mon, 21-Oct-85 10:19:02 EDT
Article-I.D.: utastro.78
Posted: Mon Oct 21 10:19:02 1985
Date-Received: Wed, 23-Oct-85 07:35:41 EDT
Distribution: net
Organization: U. Texas, Astronomy, Austin, TX
Lines: 22

[]
The trouble with graduate students is that they`re too smart.
OK I said that restricting the phase space of decay products was
the only way to change decay rates through the environment.
One Jeff Brown (stand up and bow Jeff) gently reminded me that
many radioactice nucleii have metastable excited states with
different decay channels than the ground state.  In other words,
in a sufficiently energetic plasma you can jiggle the nucleii
and persuade them to decay faster.  Typical energies required
are about a few Mev or temperatures of about a billion degrees
absolute.  I'm not a nuclear physicist, but I suspect there
are nucleii where states exist that are almost degenerate with
the ground state and require smaller temperatures to excite.
I couldn't say which common radioactive atoms might have these
states.

-- 
"Superior firepower is an      Ethan Vishniac
 important asset when          {charm,ut-sally,ut-ngp,noao}!utastro!ethan
 entering into                 ethan@astro.UTEXAS.EDU
    negotiations"              Department of Astronomy
                               University of Texas