RE: RADSAFE: static and alpha whole body monitors?

["Lavera, Ron" <Ron.Lavera@nypa.gov>]

We used to have these types of problems with the NE IPM-7 Whole Body Frisker
( gas proportional detectors ).  There were several contributing issues
including humidity penetration of the mylar.  We went to a thicker mylar,
which reduces the moisture penetration.  We also selected a different gas
mixture ( P-5 instead of P-7.5 or P-10 ).  This allowed us to change the
detector operating voltage which, again, reduced the spurious count rates.

Hope this helps.

...  mine and mine alone  ...

Ron LaVera
Lavera.r@nypa.gov

		-----Original Message-----
		From:	Fritz A. Seiler [mailto:faseiler@nmia.com]
		Sent:	Wednesday, September 01, 1999 2:46 PM
		To:	Multiple recipients of list
		Subject:	Re: RADSAFE:  static and alpha whole body
monitors?

		Dear David,

		        I am writing a short note to the list RISKANAL, and
would
		like to use your letter, (shortened as shown below) asking
for help
		with your problem, as an example how RISKANAL can get a bit
		more practice oriented.  Please, let me know whether you
agree.
		        To some people, your problem may appear mundane, to
me
		it is not.  I may be mostly a theoretician these days, but I
used to be
		an experimental nuclear physicist, and I can see that you
have a neat
		problem.  About 15 years ago, I worked theoretically with
aerosols
		of salt and plutonium and their effects on the continuous
air monitors
		at the WIPP.  All I that can think of at the moment is to
cover or
		replace critical surfaces (i.e. potential deposition
surfaces) with a thin
		removable layer of the same material at the same electrical
potential,
		remove it and see with an alpha counter what you get.  Once
you
		find the critical surface, a number of corrective actions
will probably
		suggest themselves to remove the contamination.

		Good luck and best regards

		Fritz

		David Levy wrote:

		> .... we think we're dealing with the following:
		>
		>      A PCM-2 set up for alpha whole body counting is
spending most of the
		>      day unable to operate due to "Background Too High"
messages.
		>
		>      We suspect this may be due to radon daughter
plate-out on the
		>      counters.
		>
		>      Has anyone had this experience and/or know of a
potential solution for
		>      it?
		>
		>      All regular and (viable) off-the-wall solutions
welcome!
		>
		>      Thank you!

		**************************

		NOTE CHANGE OF ADDRESS

		***************************

		Fritz A. Seiler, Ph.D.
		Principal
		Sigma Five Associates
		P.O. Box 1709
		Los Lunas, NM 87031
		Tel.    505-866-5193
		Fax.    505-866-5197
		e-mail: faseiler@nmia.com

		***************************


	
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