Re: Ni-63 portable detector

[Wes Van Pelt <VanPeltW@mail.IDT.net>]

Johannes Strydom wrote:
> 
> Radsafers,
> 
> 
>         I am interested in purchasing a survey instrument (not a LSC)
> for detecting low-level beta radionuclides.  My particular interest is
> in Ni-63, but if I can get one that will see tritium too that would be a
> bonus.  If any of you out there have and use such an instrument I would
> appreciate any comments you might have on it (pro or con).  Thank you.
> 
>                                         Fritz Strydom
>                                         Health Physicist
>                                         Georgia Tech
>                                         fritz.strydom@nnrc.gatech.edu
Fritz and Radsafers,

I have used a Ludlum Model 43-68 probe for detecting Ni-63 contamination
while decommissioning a large building.  It is a gas flow proportional
probe with a thin mylar window and 100 cm2 nominal area.  We got up to
about 5% counting efficiency, i.e., counts per decay, with a plated
Ni-63 standard in contact with the probe. As the distance between the
source and the probe increases, even by about 1 cm, the efficiency drops
off.

Good luck, Wes

-- 
Wesley R. Van Pelt, Ph.D., CIH, CHP                   KF2LG
President, Van Pelt Assoc., Inc.      vanpeltw@mail.idt.net
Consulting in radiological health and safety.
"TIME, its what keeps everything from happening at once."