[ RadSafe ] Fe-55 on LSC

[John R Johnson]

Good points Mike

John
***************
John R Johnson, PhD
CEO, IDIAS, Inc.
4535 West 9th Ave
Vancouver, B. C.
V6R 2E2, Canada
idias at interchange.ubc.ca

----- Original Message ----- 
From: "Michael Bohan" <mike.bohan at yale.edu>
To: <radsafe at radlab.nl>
Sent: Friday, February 29, 2008 10:52 AM
Subject: Re: [ RadSafe ] Fe-55 on LSC


> Hello RadSafers,
>
> I used to leak test an Fe-55 source that was used to QA an x-ray 
> microscope.  The NRC, in the licensing process, insisted that I had to 
> demonstrate my LSC efficiency for the wipe tests, so I also had to 
> purchase a liquid Fe-55 standard ampoule from what was then Isotope 
> Products Lab, which is now Eckert & Ziegler Isotope Products.  From that I 
> made a LSC standard with a contained activity of 0.211 uCi.
>
> Using the standard tritium LSC window, I was able to get an efficiency of 
> around 14 - 20%, over the years I performed the tests.  However, if you 
> are going to do this and you need to demonstrate the results to 
> regulators, you will have to manufacture your own standard or have some 
> one make it for you.  You'll need to make sure they use the same type of 
> vial and scintillant that you plan to use.  The energy is so low that 
> quenching and other factors can easily affect your efficiency.
>
> Regards,
>
> Mike Bohan, RSO
> Yale-New Haven Hospital
> Radiological Physics
> 20 York St. - WWW 204
> New Haven, CT 06510
> Tele: (203) 688-2950
> Fax: (203) 688-8682
> Email: mike.bohan at yale.edu
>
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