Personal Alpha CAM (PCAM)

[Ron Morgan <rgmorgan@lanl.gov>]

I am the co-inventor of a lapel-mounted alpha CAM called the PCAM, with a
battery/electronics pack worn on the belt.  It is currently in the
integration/beta-testing phase of development.  We invented it because of
problems with fixed CAMs that we (the inventors) felt we could overcome.
Consider, for example, the huge sample dilution rates that usually
accompany the use of a fixed CAM (normally a factor of 100 to 1000), and
the expensive (and usually not-well-done) airflow characterization studies
that are required.  A lapel-mounted CAM does not have the high sample rates
that a fixed unit enjoys, but the fact that the breathing zone is always
being sampled may (emphasis on may) provide a net benefit.  Radon IS a
problem with a lapel sampler if an MCA cannot be utilized (we're working on
it), but how much radon would you expect in an air hood?  Also, dust
buildup should not be as large a factor in lapel sampling as it is in fixed
CAM sampling (lower flow rates, shorter run times).  We feel we may
(emphasis on may) be able to effectively compete with fix CAMs, given that
the project runs as we expect it will (i.e. we don't run into any technical
or financial brick walls).

On 25 Jan 99 10:21:36 Bill Lipton wrote:
Please consider: 
 
1.  How's someone going to carry the detector and electronics, eg., a 
photomultiplier tube!, on his lapel? 
 
2.  Even if you could, how would you separate the TRU from the Rn daughters?
 
For example, assume that the airborne concentration of Pu-239 is 100 DAC = 3 
E-10 uCi/ml.  Assume that the cam is operating at the reference man
breathing 
rate of 20 liters/min.  Then, the cam would sample 9.6 E6 ml in an 8 hour 
shift, and, assuming 100% filter collection efficiency, the total activity 
sampled would be less than 3 nCi.  I doubt that this can be detected by 
available instrumentation without letting the background decay.  Dust
buildup 
on the filter would degrade both the detector efficiency and the alpha 
spectrum, so I doubt that, even with spectroscopy, the TRU alphas could be 
separated out in real time.    
 
3.  Why do you feel the need to provide alpha cam's?  Your radiological 
controls should be good enough to prevent sudden changes in airborne levels 
during routine operations.  For those nonroutine operations, such as system 
breaches, where there is a likelihood of a release, the workers should be 
wearing adequate respiratory protection. 
 
The opinions expressed are strictly mine. 
It's not about dose, it's about trust. 
 
Bill Lipton 
liptonw@dteenergy.com 
 
You wrote: 
 
>Does anyone know of a lapel type/size alpha continuous air monitor.  This 
>device would provide a continuous indication of alpha airborne
radioactivity 
>to the wearer. 
 
>Please respond to: 
 
>Tom Goff 
>Rad Engineering 
>Rocky Flats ETS 
>Tom.Goff@RFETS.gov 

*********************************************
   Ron Morgan
   Radiation Protection Services (ESH-12)
   Los Alamos National Laboratory, MS K-483
   Los Alamos, New Mexico, 87544 (USA)
   Phone (505) 665-7843
   FAX   (505) 667-9726
   Mailto:rgmorgan@lanl.gov
*********************************************
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