RE: tritium air monitors

["Edwards, Richard W" <Richard.Edwards@PSS.Boeing.com>]

Gee, it must be instrument question week.

I like the Overhoff instruments. The new 400 series are quite portable
(6 pounds), capable of measuring down to 1 microcurie/cubic meter and
have a small magnet which can be used to switch off the gamma
compensation and permit source checking these with an external gamma
source.

For a bench mount, I've used several of the old Johnston units. They
were bought out years ago by Becton-Dickinson, which may tell you how
old these are. The bench mounts work quite well. I find the "portable"
units to be too heavy to cart around. they weigh in at 26 pounds. Also,
the ones I have use a very expensive, non-standard battery.

I haven't tried Scintrex's units.

Rick Edwards, Analyst
The Boeing Company
richard.w.edwards@boeing.com