RE: Radiation Detector Calibrations

[Herrold@uwyo.edu (Jim F. Herrold)]

Three references for calibrations are: NRC Regulatory Guide 10.8, Appendix 
D,  ANSI Standard N323-1978 and NCRP 112.

For photons we use a combination of Cs-137 for mR/hour calibrations plus 
pulse generator for fine tuning. The pulse generator saves a lot of time and 
unnecessary exposures, but you still need to know how your instrument reacts 
to radiation. If you are detecting betas, ANSI  says you should use 
"similar" isotopes for calibrating. Since beta efficiency is dependent on 
energy, you need a series of calibration sources. Because NIST standards 
aren't cheap, we've opted for plated sources of increasing energies (C-14, 
Tc-99, Sr-90). We plot the efficiencies for these isotopes, then calculate 
efficiencies for other isotopes from a calibration curve.

Jim Herrold, RSO
University of Wyoming
herrold@uwyo.edu
 ----------
From: radsafe
To: Multiple recipients of list
Subject: Radiation Detector Calibrations
Date: Wednesday, June 26, 1996 11:39AM

Time for a new topic.

I am trying to determine the "best" way to calibrate a survey instrument 
(i.e.
Ludlum III.)  There have been two methods proposed: A pulse generator or a 
Cs-137
Calibration source. Any information would be appreciated.
 --
Eric A. Goldman, B.S.,CNMT
Baylor University Medical Center
Department of Medical Physics/Radiation Safety
Dallas, Texas  75246
(214) 820-3870

"Gotta run, the cat's caught in the printer."