Re: ?? Ra-226 in computor tubes

[gfeldman@uci.edu (Gerald Feldman)]

Alan:

These tubes may be gas-filled switching tubes (thyratrons).  To stabilize
the firing voltage of these tubes, the manufacturer would sometimes add a
little radioactive material (a pinch of this, and a pinch of that).  I don't
remember Ra-226 ever being mentioned as the material of choice, though.

By the way, George Philbrick is best known as the inventor of the
"operational amplifier", the basic building element of the _analog_ computer
(as opposed to the digital computer).  Philbrick's invention allowed the
construction of stable DC amplifiers which were used in many of our
dosimetry instruments.

I have an old Philbrick data book somewhere in my archives, so if you can
fax me a sketch of the tube, I may be able to identify it for you.


..................................reply separator....................
>A researcher in our physics dept. is closing his lab, so we went over to
>decommission his lab.  It is not unusual to find various 'goodies' when
>doing this, and today was no exception.  We found a number of these double
>vacuum tubes which when placed in the multichannel analyzer gave the
>characteristic Ra-226 signature.  
>
>The tubes are labelled: GAP/R Computor (yes, with an 'or'!!) Tubes, Model
>K2-W.  They were made by George A. Philbrick Researches Inc., Boston 10,
>Mass.  One is dated 1965.
>
>Q:      Why Ra-226?  How much was used per double tube?  Disposal problems??
>
>thanks in advance, 
>
>Alan Enns 
>aenns@unixg.ubc.ca
>Radiation Safety, UBC.
>
>
>
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