RE: Field measurement of hard-to-detect radionuclides

["Vollmer, Jeffrey S" <Jeffrey.Vollmer@MKG.COM>]

	Quang said"Thin window GM detectors should be able to see
> C-14, so you may want to do a GM check in conjunction with your
> scintillation-probe check"  A GM detector should be able to find all of
> the nuclides you listed by the energy of beta each emits C-14(156keV),
> P-32(1.711MeV) P-33(249keV) S-35(167keV) Cr-51(753keV)
> 
As for Ni-63 beta (67keV) it is a low enough energy not to penetrate the
dead layer of skin.  I assume the best way would be to use an open air
proportional detector such as Ludlum Model 44-110 used for tritum detection.

Jeffrey S. Vollmer
RSO
Mallinckrodt Inc.
jeffrey.vollmer@mkg.com 
> ----------
> From: 	Quang Le[SMTP:quangle@SLAC.Stanford.EDU]
> Reply To: 	radsafe@romulus.ehs.uiuc.edu
> Sent: 	Wednesday, October 20, 1999 11:42 AM
> To: 	Multiple recipients of list
> Subject: 	Re: Field measurement of hard-to-detect radionuclides
> 
> Grant,
> 
> At my previous job, contamination control was a big part of our program.
> We
> dealt with curie amounts of "loose" H-3, C-14, P-32, P-33, S-35, Cr-51,
> iodines... The best way we found that would give us confidence to release
> objects and people is to swipe check them and run the swipes through an
> "open window" liquid scint. counter. I realize this may not be a good
> option for large facilities. Thin window GM detectors should be able to
> see
> C-14, so you may want to do a GM check in conjunction with your
> scintillation-probe check. I am not so sure about Ni-63 though. If you
> have
> the luxury of time and knowledge of the nuclides involved AND these
> nuclides have considerably different half-lives, you may be able to take
> measurements at half-life intervals and set up a system of equations to
> solve for the contributing activities. Just some random thoughts. Hope
> they
> can help.
> 
> 
> are Ni-63 and C-14, in proportions that typically are 25% or less.
> However,
> we have seen one sample that shows the proportion to be as high as 77% of
> the total activity.
> 
> .
> 
> 
> Any information or suggestions would be welcome.  Please post either back
> to
> RADSAFE, or reply directly to GMCeffal@bhi-erc.com.>>>>
> 
> 
> 
> 
> _____________________________________________________________________ 
> Quang Le 
> SLAC/OHP 
> (650) 926-2610 
> <quangle@slac.stanford.edu> 
> Note: The above is my own opinion only!  
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