[ RadSafe ] Can tritium produce bremsstrahlung?

Wed Feb 22 11:07:55 CST 2006

I can tell you that 100-120 mCi of Tritium on a Scandium or Titanium flashed
steel foil 3/8" x 3/8" is readily observable using a pancake type detector.
NSSI has used this method to determine which side of the foil is the active
side. I would guess based on the counts we see that one could probably
observe the brems down to 10 mCi  and maybe 1 mCi.

It is certainly not a technique that could be used for routine monitoring
for Tritium.

With respect to the exit signs, the individual tubes in the sign are either
covered by a piece of plastic or glass and in some cases the tubes are
encased in Epoxy. Though the signs contain when new, 21-25 Ci of H-3, The
brems have to get through a lot of shielding before they are measured by the
counter.

Bob Gallagher
NSSI

-----Original Message-----
From: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl]On
Behalf Of Jean-Francois, Stephane
Sent: Wednesday, February 22, 2006 6:40 AM
To: 'JGinniver at aol.com'; stiegli1 at msu.edu
Cc: radsafe at radlab.nl
Subject: RE : [ RadSafe ] Can tritium produce bremsstrahlung?

Can you share the reputable sources that tells you that H-3 (in any amount!)
can be detected by a Beta pancake ? A Geiger counter (gas chamber
technology, this is what UI assume you are saying by "pancake") is very bad
for detecting X-rays, less then 1 % efficiency for pancakes if my memory
serves me well. So obviously "any amount of H-3" is a bit far fetch for a
pancake. I would not recommend AT ALL to use a pancake for tritium, beta
will not go through the window and Bremstrahlung will not be detected. Is
this a clear answer ?

Let's but it this way: I have a large tritium lab (37 TBq...oups, 1000 Ci)
here and I would be VERY HAPPY if I would be able to control contamination
with a pancake.  Please check your sources for info.

This is not a stupid question, hopefully MY ANSWER is not stupid either !

Regards,

Stéphane Jean-François, Eng., CHP
Manager, Environmental and Health Physics services
Merck Frosst Canada
514-428-8695
514-428-8670
stephane_jeanfrancois at merck.com
www.merckfrosst.com

-----Message d'origine-----
De : radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] De la part
de JGinniver at aol.com
Envoyé : Tuesday, February 21, 2006 5:35 PM
À : stiegli1 at msu.edu
Cc : radsafe at radlab.nl
Objet : Re: [ RadSafe ] Can tritium produce bremsstrahlung?

In a message dated 21/02/2006 21:25:10 GMT Standard Time, stiegli1 at msu.edu
writes:

Could  someone please tell me if a beta pancake is able to detect tritium in
any  amounts?  I have heard from reputable sources that it can.   Obviously
the beta is too weak to be detected so as I understand it, the  only way
would be to detect the bremsstrahlung radiation.  Is tritium  energetic
enough to produce bremsstrahlung?  Can anyone tell me how  much would be
needed?  I apologize if this is a stupid question but  nobody has totally
answered the question to my  satisfaction.

According to the Lawrence Livermore National Laboratory "Because this
attenuation and/or stopping process produces a bremsstrahlung radiation, the

detection of this tritium bremsstrahlung appears to be the most direct and
advantageous way to monitor for STP [stable metal tritides] air
contamination.".
They have a short article on the development of a CAM for  the measurement
of
STPs at : _http://www.llnl.gov/es_and_h/hc_dept/spd/MetalTritides.html_
(http://www.llnl.gov/es_and_h/hc_dept/spd/MetalTritides.html)

However it's not clear what measurement technology they are planing to use
for the detector.  Most modern CAM use Passively Implanted Planar  Silicon
(PIPS) detectors.  I would have thought that if it was possible to  use a
pancake
geiger to measure tritium bremsstrahlung, then things like  the 'Flat
Ferret'
from Overhoff would not be in production.

Regards,
Julian
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