Re: Looking For a Calibration Facility

[JSBland@AOL.COM]

Mike,

If can't find the Ra-226 source, why not do a three point energy  calibration 

curve?  Also a word of caution, a calibration using a typical  

source/detector arrangement to come up with a cpm per uR/h  correlation may not be directly 

applicable to field conditions, especially  for volumetric contamination where 

Compton scatter gammas (which have lower  energy) will comprise a large 

fraction of the gamma flux at the detector.   For example, for contaminated soils, 

more than 50% of the gamma flux above the  ground surface is from Compton 

gammas.  So, assuming the detector response  based on the principal gamma energy 

alone will not be correct.  In the past  I have used MCNP modeling coupled with 

field verification to address this  situation. I am giving a paper on this 

subject at the HP Meeting in  DC.  Give a call if want to discuss further.

 

J. Stewart Bland

_jsbland@chesnuc.com_ (mailto:jsbland@chesnuc.com) 

Chesapeake Nuclear Services

410-266-9174