H-3 Monitor

[SWEIS <sweis@roadrunner.com>]

Fritz and other Radsurfers, 

I read your posting on Radsafe, some good information passes by here everyso
ofton. I tried to send the following direct but had a bad address, oneelse
interested please feel free to read on.
I have used the Technical Associates Tritium Surface Contamination Monitor
during a tritium D & D job.

Be sure to purchase the sealing kit (one sided self stick foam) to attach to
the probe. If you are survaying a flat surface it will cut down on the
amount of counting gas needed. (The job I did was at a specility gas
facility that used to provide H-3 gas to clients. They had a couple of rooms
that had to be deconned and survayed, so no problem with counting gas (P-10)
availability). 

If you have to survey a large area or meny areas consider adapting a 100
liter cylinder, with reducing valves, and enough tygon tubing to get around. 

The unit itself is OK, just watch out for the cathod grid wire, it is very
thin and will not take the strain of being poked. It can be deconned using
alcahol and careful use of Q-tips. Do not attempt to replace the wire
yourself, to frustrating.

If you project a lot of work or use by minimumly trained individuals
consider optaining two probe units.

When surveying rough surfaces remember that the gas seal is not tight and
has to be broken when the probe is moved. This requires longer time for the
unit to stabilize befor an accurate reading can be obtained (sometimes up to
5 seconds after opening the gas valve on the probe). Even on flat surfaces
you will be surprised at how many times the counting gas has to be replaced
when sliding the probe along the surface.

TA is the only company that I know of that makes a unit to detect tritium
surface contamination. 

If you have additional questions I am

Robert Monsalve-Jones, NRRPT
currnetly reachable at
GRAM, Inc.
974 17th street
Los(T) Alamos, NM 87544

(505)661-6700  vioce
(505)661-6705  fax
sweis@roadrunner.com       e-mail

Good luck.
Robert.