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From: ethan@utastro.UUCP (Ethan Vishniac)
Newsgroups: net.physics
Subject: Re: decay rates and temperature
Message-ID: <87@utastro.UUCP>
Date: Tue, 22-Oct-85 11:53:28 EDT
Article-I.D.: utastro.87
Posted: Tue Oct 22 11:53:28 1985
Date-Received: Thu, 24-Oct-85 06:05:47 EDT
References: <78@utastro.UUCP> <2310@brl-tgr.ARPA>
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Organization: U. Texas, Astronomy, Austin, TX
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> I don't know about affecting the decay RATE as such,
> but a powerful technique for investigating magnetic
> critical point behavior is to dope the sample with
> an isotope that decays via a pair of oppositely
> directed gammas, and put the sample in an aligning
> magnetic field with gamma detectors around the setup.
> By studying the gamma-gamma correlations one can
> infer the magnetic field near the probe nuclei.
> (This technique is called "Perturbed Angular
> Correlation"; it was a specialty of CLark University
> not very many years ago.)  Temperature effects are
> quite evident in this experiment, so temperature can
> have detectable effects on nuclear decay.

Hmm...  I have a question about this.  It seems
clear that the correlations are produced by correlations
between the direction of emission and the direction of the
magnetic moment of the nucleus.  Wouldn`t the temperature
effects be due not to changes in the decay rate but from
fluctuations in the alignment of the nucleii with the external
field?

Not afraid to show my ignorance.
-- 
"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