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Re: radon measurement
-----Ursprüngliche Nachricht-----
Von: Jean Charles ABBE <Jean-Charles.Abbe@IRCCYN.EC-NANTES.FR>
An: radsafe@list.vanderbilt.edu <radsafe@list.vanderbilt.edu>
Datum: Mittwoch, 11. Juli 2001 12:18
Betreff: radon measurement
>From our own experience, we find that using the picorad procedure as
developped by Packard is rather good and safe for Radon measurement over a
few days. However, the liquid scintillation equipment is expensive. Is
there any scintillation device, simple and just dedicated to such
measurements on the market ? Any comment welcome. Thanks.
-----------------------------------------------------------
Dear Jean Charles,
I have worked for years with the Picorad-System and have done tens of
thousands of measurements in the framework of the Austrian Radon Project and
of course dealt a lot with the basic questions. The method for LSC was
introduced by Prichard and Gesell (or Gesell and Prichard?). The
Picorad-Vials are produced by the Niton Company (you might know, that Niton
was another name for Radon in old days) and distributed (partially?) by
Packard.
Regarding the "expensive liquid scintillation equipment" I do not really
share this opinion. One has to take into consideration several aspects like:
What is the number of samples to be measured in which time span? What are
the costs for alternative methods - including costs for equipment,
investment costs for instance for track-etch "cups" or the electret devices,
personnel and possibly travel costs for on-site measurements? What will be
accepted by the inhabitants of the houses - will they accept a continuous
measurement device with an air pump in their bed-room?
I have used for our measurements always the Ultra Low-Level Liquid
Scintillation Spectrometer "Quantulus" from Wallac Oy - I had four of them
in my laboratory and we have done - except gamma-spectrometry - all our work
on these counters (Sr-90, Radium and Radon in Water, Radon in Air, C-14 in
alcohol, tritium and gross alpha-beta in drinking water and waste water from
nuclear research reactors etc). During the campaigns of the Austrian Radon
Project we really needed them, because we sometimes had to measure two- or
threethousand samples within a few weeks. The extremely low background made
it possible to use short measurement times, therefore enhancing throughput
in such a way that these campaigns could be handled in time.
I was confronted once with the accusation that we were using such expensive
equipment at a conference in Seville on Low-Level Counting. I then made a
very quick calculation, which showed, when comparing the costs with costs of
electret or track-etch methods, the cost of a "Quantulus" was saved within
two years of operation - only for the Austrian Radon Project, not taking
into account the many other uses of the LS equipment as I mentioned above.
If you have only occasionally the need to measure Picorad Vials, there
exists a much cheaper instrument, the "Triathler" from HIDEX, which has no
sample changer, but has an excellent alpha-beta-discrimination unit (like
the Quantulus), which reduces background to practically zero. I have worked
a little with this instrument and therefore I know, that it works well. You
can find more information at http://www.hidex.com.
I have not worked with other instruments -there was no need to - so I cannot
give any information about their suitability.
In case you would like more information, especially on the "religious war"
of short-term measurements and long-term measurements, please contact me.
There is much in the literature and also we have done comparative
measurements.
Best regards,
Franz
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