High Energy Gamma Emitter -Reply

[FRAMEP@ORAU.GOV]

>Of all the isotopes, which one emits the highest energy gamma? We
>have a need for calibration of a wide energy-range detector. Other
> than Co-60,and short of letting my fingers do the walking through the
>pages of the Rad Health Handbook, I couldn't come up with it off the
> top of my head.
>So, to save a litle time, I thought of the great resource of Radsafe!

Don, o lazy one:

You didn't say whether this was for an efficiency or an energy
calibration. A commonly used isotope for efficiency calibrations is Y-88
with a gamma over 1800 keV (I'll let you look up the exact value). But.
Theres no free lunch - its short lived with a half life a little over 100 days.
A commonly used rule of thumb is that you don't want a standard to be
more than two half lives old. 

If you had a radium source with good numbers on it, you could try the
high energy gamma from Bi-214 (1764 keV). Of course, this line can
show up in the background as well.

Best of luck

Paul Frame
Professional Training Programs
ORISE
framep@orau.gov