Re: Q:film badges and filter patterns

["Sandy Perle" <sandyfl@earthlink.net>]

> Out of curiousity, above what photon energy would one expect to get "no
> filter pattern" using Landauer's standard beta/gamma film badge holders
> and G1 film?  The service rep I talked to on the phone didn't know.
> 
> The film badges that I placed out at our rad waste facility came back with
> doses ranging anywhere from 70 - 1450 mrem (1 month), high energy photon
> (i.e., >250 keV effective), and no filter pattern.

The fact that filter patterns are not seen on a film dosimeter really 
has nothing to do with photon energy. When there are no patters, it 
is most likely that the film was NOT in the holder, the film was 
exposed to extreme heat (film is completely dark). Film exposed to 
Co-60, I-131, high energy photons always show a reliable filter 
pattern, EVEN at 10 mrem. If the film is entirely clear, it was NOT 
irradiated, or, there is a problem with the development.

In summary, filter pattern display is NOT a function of energy, be it 
gamma, x-ray or beta.

------------------
Sandy Perle
Technical Director
ICN Dosimetry Division
ICN Plaza
3300 Hyland Avenue
Costa Mesa, CA 92626
Office: (800) 548-5100 x2306 
Fax:    (714) 668-3149
  
sandyfl@earthlink.net
sperle@icnpharm.com

ICN Dosimetry Website:
http://www.dosimetry.com

Personal Website:
http://www.geocities.com/CapeCanaveral/1205

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

The opinions expressed are solely, absolutely, positively, definitely those of the author, and NOT my employer
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