Re: GM Quench Gas

["Ron L. Kathren" <rkathren@tricity.wsu.edu>]

Back in the old days, GM tubes were not of the self quenching variety, and a
special fill gas containing a small amount of an organic or halogen
quenching compound was used.  The fill gas itself was typically largely
argon, and one common mixture for an organically quenched tube was a mixture
of 90% argon and 10% methane.  Ethanol was also used as were other organics
(ethyl formate) and carbon dioxide.  Halogen quench tubes, which actually
came along latger than organic quench tubes used a very small amount of
chlorine (usually) or bromine to provide quenching.   Quenching was provided
by the dissociation of the halogen molecule which later recombined,
providing a tube with essentially an unlimited lifetime, unlike the organics
which dissociated but did not recombine.  Hence a relatively large
percentage of organic was used, as indicated above.

Now, having given you this background, which I hope is not too tedious, it
is very reasonable to conclude that the gas in question is not radioactive,
and mostly (or virtually all) argon.  I'd put my money on the 90-10
argon-methane or alcohol mix.

Ron Kathren
-----Original Message-----
From: Susan Radosevich <Susan.Radosevich@ehs.ucsb.edu>
To: Multiple recipients of list <radsafe@romulus.ehs.uiuc.edu>
Date: Wednesday, July 28, 1999 3:07 PM
Subject: GM Quench Gas


>Hello all,
>
>We recently came across a gas tank which is dated 1969 and is labeled
>as "GM Quench Gas".  The company listed on the bottle is
>Nuclear-Chicago.  I was wondering if anyone could provide a phone
>number or any relevant information about the company.  We are
>trying to identify the gas for disposal.
>Thanks,
>
>Susan
>
>
>My own opinion.
>----------------------
>Susan R. Radosevich
>Radiation Safety Office
>University of California, Santa Barbara
>phone: (805) 893-7255
>Susan.Radosevich@ehs.ucsb.edu
>
>
>
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