Gamma Peaks -Reply

[FRAMEP@ORAU.GOV]

>I observed two interesting peaks when analyzing an object containing
>a small amount of U-234 and U-235. Peaks were very apparent at about
>75 keV and a slightly smaller one at about 240 keV. I've looked at U
>progeny analysis via RADDECAY and nothing seems to figure. The
>detector was a 3x3 NaI. Any ideas out there?

Enriched uranium? No U-238 to speak of? Weapons grade? 

U-235 has gammas at 74.98 and 240.9 keV but of such low intensities
you wouldn't pick em up with NaI.
The 75 keV might be a Pb-xray from either the sample or shield. 
The 240 keV could be Pb-214 or Pb-212 but they have plenty of other
peaks.

I'd say we need a more complete description of the rest of the
spectrum. ie what are the other peaks. A description of the nature of
the sample would be helpful too.

Paul Frame
Professional Training Programs
Oak Ridge Associated Universities
framep@orau.gov