Re: GM Response (formerly Respect) -Reply

[LIPTONW@dteenergy.com]

I made that statement thinking it was a moot point, not realizing that 
windowless counters are still in use.  I ran into this at Argonne National 
Lab, where we sometimes used a windowless internal proportional counter.  
Nonconducting materials, such as paper, build up static charges.  This
charge 
may be strong enough to alter the electric field lines within the detector, 
and, hence, the counting efficiency.  Since the static charge distribution 
changes from sample to sample, this leads to nonreproducible results.  I
know 
of 3 ways to overcome this:  (1) use a windowed counter, if feasible; (2)
use 
a conducting sample - I've seen carbon-impregnated smears; (3) put a
material, 
such as mylar, over the sample, essentially making this a windowed counter. 
 
The opinions expressed are strictly mine. 
It's not about dose, it's about trust. 
 
Bill Lipton 
dteenergy.com 
 
You wrote: 
 
<Bill, would you please elaborate on your statement below?  This is 
<an issue we are susceptible to with our usual met. conditions (i.e., 
<high and dry!).  Thanks! 
 
<Michael 
<mford@pantex.com 
>>>>>>>>>>>>>>>>>>>>>>> 
<One final point and I'll leave you alone. Use a great deal of caution 
<if you use a windowless counter for assaying nonconducting 
<sources, such as smears or air samples.  Static charge buildup 
<may lead to nonreproducible results.... 
 
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