Re: TLDs - False Positive Betas

[jgbarnes@ix.netcom.com (JAMES BARNES)]

Dear Stu,

This happens to use once in a while.  When it does, according to our 
vendor, the problem has normally been physical contamination (dust, 
paint, solvent, etc.) of the chip in the "beta" position on the card.  
It apparently gives a flash during the heat cycle that is easily 
misidentified by the computer reader as a true dose.

My understanding is that it is identified when a human eyeball looks at 
the glow curve.  The curve will display a "spike" or some other type of 
anomalous shape.

One other point; as you are from Northeast Utilities, I am assuming 
that your folks aren't working around low-energy x-ray systems.  That 
can sometimes be misID'd as a beta exposure.

Jim Barnes, CHP
RSO
Rockwell International, Rocketdyne Division

=============================
You wrote: 
>
>Has anyone experienced "false positive" beta responses with 
>their TLDs? We  have performed glow curve analyses on these 
>responses which say that there is a real beta response but 
>our TLD users say that there is no beta. Any comments?  
>
>Thanx
>
>Stu Torf
>torfsm@nu.com
>RP section
>Northeast Utilities
>203-665-5814
>
>P.S - whatever the standard disclaimers are, they apply.
>
>
>
>