Re: environmental dose rate

[schoenho@via.at]

At 13:15 20.08.1996 -0500, you wrote:
>I want an instrument with a sensitivity adequate
>to see changes in dose rate of 0.01 microrem/h
>(0.1 nSv/h).  The purpose is to directly measure
>public dose from the facility Ar-41 emissions.
>
>The 16 L Reuter-Stokes ion chamber has a sensitivity
>of 0.1 urem/h.
>
>NaI and similar spectroscopy techniques require fairly
>complex spectrum unfolding methods, particularly for a
>mixed spectrum from an elevated plume.  It's possible
>that a proportional detector would do this, but I have
>not seen one.
>
>Having just toured the HPS exhibits with no luck, I thought
>I would see if anyone knows of commercially available
>instrumentation with this sensitivity.  Of course, the
>system has to be able to operate outside in cold/hot weather
>(a minor challenge for instrument designers of today's caliber).
>
>Given the specialized nature of this query please reply to me.
>I will summarize responses for the list.
>
>A little risk adds spice to life.
>slaback@MICF.NIST.gov
>
>===================================================================

I think that such an instrument would be a miracle and of interest to all
radsafers........

How are you going to distinguish a dose rate of 0.1 nSv/h due to Ar-41 from
fluctuations of radon in outdoor air or changes in cosmic ray dose or
changes in terrestrial dose rates due to changes in weather conditions? 

I remember from discussions many years ago that Ar-41 could be measured in
the hall of a research reactor in air by simply putting a Ge-Li detector
there, but I do not remember the details. I remember that Ar-41 could be
detected in the body of persons working in this nuclear research facility by
whole body counting with a NaI-system. The contribution to the dose of these
people was so ridiculous low that I do not think it is worth any discussion.
Since there is no risk associated, I miss the spice .......

I am interested in the outcome of your request. 

Best regards, Franz

Franz Schoenhofer
Federal Institute for Food Control and Research
Vienna, Austria
Schoenhofer
Habichergasse 31/7
A-1160 WIEN
AUSTRIA/EUROPE
Tel./Fax:	+43-1-4955308
Tel.:		+43-664-3380333
e-mail:		schoenho@via.at