Why freeze autorads?

[S. Silverman]

Samuel C. Blackman wrote:
> 
> My labmates and I, obviously with too much time on our hands, were
> wondering why we put our 32P-labelled autorads in the freezer at -80C.
> Our advisor hypothesized that the low temp. promotes a more "focused"
> autorad, but without a good explanation for that.  The decay equation
> has no mention of temperature, so we're stumped.  Any ideas?
> 
> -- Sam
> 
> --
> Samuel C. Blackman        ! InterNet : blackman at tigger.uic.edu
> MD/PhD Student (4/8)      ! Disclaimer: I speak for me, not UIC!
> Univ. of Ill. at Chicago  ! Quote : "Quandro potro io finir di stupire?"
> Dept. of Pharmacology     ! Phone : 312/996-4983 (lab)  Fax: 312/996-1225

	The absorption and emission properties of the material in 
intensifying screens depend on temperature.  The screens are more 
efficient at low temp.  It will take someone with more familiarity with 
molecular orbital theory than me to give you a more precice reason.  This 
is probalby the origin of "put in in the freezer" mentality.  Also, 
perhaps, the thought that for long exposures, the material in the bands 
will diffuse less.

--------Sandy
-- 
Sanford Silverman               >Opinions expressed here are my own< 
American Cyanamid  
silvermans at pt.cyanamid.com                      "Yeast is Best"