Re: Simulated gas standards

["Sandy Perle" <sandyfl@ix.netcom.com>]

Did you get a copy of their NIST traceable certificate? If not, 
request a copy AND their procedures used to perform the calibration. 
The methodology may help you decide which one is more appropriate for 
your activities. It is quite possible that they both meet NIST and 
still be different. I see this when using two source calibration 
facilities that are both NIST traceable and provide different 
exposures for Tl-204, as an example. Sometimes the Standards are such 
that two NIST traceable facilities will derive a different result.

As Bill said, 2 sources .. you don't know where you are. Get another 
and use the average of the two closest. Or, follow above 
recommendation. If the desired results are not critical, and, you're 
only looking for 95% Confidence Levels, just chose one and go with 
it.

Sandy Perle
Director, Technical Operations
ICN Dosimetry Division
Office: (800) 548-5100 Ext. 2306 
Fax: (714) 668-3149

E-Mail: sandyfl@ix.netcom.com