Calibration Standards for Gamma Counter

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

Good Afternoon Radsafers,

I need advice on available gamma standards for routine calibration of an
automatic gamma counter.  The standards would be about 0.01 to 0.5
microcurie in a small "test tube" format for calibrating an automatic
gamma counter which uses a well-type NaI crystal detector.

In particular, I am looking for long lived (i.e., more than 1 year)
radionuclides which could be used to calibrate for the following short
lived isotopes. That is, I am looking for long lived nuclides which have
similar gamma energies to those of the short lived ones. I would think
that the nuclear medicine community would use such calibration standards
routinely.

Tc-99m		0.141 MeV
Cr-51		0.320 MeV
In-111		0.171, 0.245 MeV
Re-186		0.122 MeV
Re-188		0.155 MeV

Thanks, 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."