RE: Low Positive Doses in Personnel Monitoring

["Sandy Perle" <sandyfl@ix.netcom.com>]

Tom Paquette stated the following:


> Shouldn't badge reporting limits be adjusted for altitude, so 
> that the false positive rate is more or less constant across the 
> country?

There is no reason  for this additional background compensation. That 
is the primary purpose of the Control badge. First to measure 
background radiation within the facility (this really assumes that 
the badges are NOT maintained in a high background, or, work area) 
and second, for transit dose subtraction. 

> And that leads to a second question, what is the expected 
> control value +/- error for TLD's?

This answer depends entirely on your system's Process Capability. If 
you have a well-controlled process, the error is minimized, whereby 
there should be NO false positives, except for chance errors, not 
assignable cause errors. As far as background, with a good TLD 
program, the average exposure depends on where you live. It is not 
uncommon to see exposure rates in the area of 6 to 10 microrem/hour. 
Therefore, the Control badges report what they are exposed to for the 
entire time period from assembly to receip back at the processing 
facility.


------------------
Sandy Perle
Technical Director
ICN Dosimetry Division
Costa Mesa, CA 92626
Office: (800) 548-5100 x2306 
Fax:    (714) 668-3149
  
mailto:sandyfl@ix.netcom.com
mailto:sperle@icnpharm.com

Personal Homepages:
http://www.geocities.com/CapeCanaveral/1205 (primary)
http://www.netcom.com/~sandyfl/home.html (secondary)

"The object of opening the mind as of opening 
the mouth is to close it again on something solid"
              - G. K. Chesterton -