I'd put the Cr51 efficiency at about 0.1 to 0.2% -- numerically, ~0.0015 - this is taking into account the geometry and yield, in other words the "absolute" efficiency, in units of cpm/dpm. So for a typical surface or smear survey, a reading of 100cpm ~ 65,000 dpm.
Anybody else have any empirical data on this?
>>Question for other University research settings: What survey
method do
>>you recommend
>>for users of Cr-51. If it is a GM with pancake probe, what
efficiency
>>have you obtained and how did you obtain it?
>>Thanks,
>>
>>D. Steva
>eff. Cr51: [(eff. Cd109 + eff. Cs137) / 2] x 10%
>for GM probe, eff. of Cr51 is about 0.04%
--
Keith Welch
Thomas Jefferson National Accelerator Facility
Newport News VA
welch@jlab.org
Ph: (757)269-7212
FAX:(757)269-5048
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