?? Ra-226 in computor tubes

[Alan Enns <aenns@unixg.ubc.ca>]

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.