Re: Radioisotope Efficiencies

[Joel Baumbaugh <baumbaug@NOSC.MIL>]

Bill, you hit the nail on the head with your comments.  As I'm sure you 

know, there are so MANY variables that could change the efficiency of 

someone's counting that I felt that if I didn't (over) emphasize the fact 

that their results could (and would) be different - some new user 

might/could/would assume that their LSC results would be exactly the same 

as mine w/o taking into account all of those variables...



Joel



At 07:27 AM 2/19/2004 -0500, William V Lipton wrote:

>I read your disclaimers with some amusement.  The fact that you feel 

>they're necessary illustrates two fundamental problems with RADSAFE:  (1) 

>It is sometimes considered a lazy person's research tool.  (2) It's 

>sometimes used by the clueless to do things that are way outside their 

>qualifications.  (I remember one posting which went something like:  "I've 

>never shipped radioactive material before.  What label should I put on the 

>package?")

>

>While RADSAFE is good for discussions and is good for leads to reference 

>materials, it should NEVER be used in place of legitimate research, and 

>should NEVER substitute for needed qualifications.  Any references 

>received on RADSAFE should be independently confirmed through a legitimate 

>source.  If someone's too dumb or too lazy to do this, the person who 

>supplies the information should not be held accountable, even if its 

>wrong.  To cite an analogy, it's often a great idea to visit "Web MD" or a 

>similar site if you have questions about a medical condition.  However, it 

>should not take the place of seeing a physician if you have reason to 

>believe you have something that may need treatment.  (Except, perhaps, for 

>those RADSAFER's who are physicians.  Even then, it may be a good idea to 

>see someone else.)

>

>The opinions expressed are strictly mine.

>It's not about dose, it's about trust.

>Curies forever.

>

>Bill Lipton

>liptonw@dteenergy.com

>

>Joel Baumbaugh wrote:

>>Jim is correct in his question.

>>

>>As I thought I briefly mentioned in my original email/post, these were MY 

>>efficiencies under somewhat ideal conditions.

>>

>>The type (size and composition) of vial, the manufacture/type and amount 

>>of scintillation fluid (in the vial(s)), counting times, color/chemical 

>>quenching, background and how you deal with background 

>>(refrigeration/background subtract), how long its been since your PM 

>>service (you don't want any dust on the PMT tube faces), what your 

>>counting windows are set at/for, what formula you use for MDA/LLD, etc., 

>>etc., etc. ALL these parameters (and some I haven't thought of while 

>>writing this) make a difference on what efficiency YOU and YOU're machine 

>>will get/arrive at with the various/sundry radioisotopes I listed.

>>

>>Just like they say in the advertisements... "your results may 

>>vary"....  I was just giving you an example of what YOU should expect on 

>>YOUR machine if everything (your prep and the machine) are in top working 

>>order.

>>

>>Please don't nail me to a cross here - I was just trying to be 

>>helpful.  There are people on RADSAFE who are MUCH more knowledgeable 

>>about LSC's than I am.

>>

>>I don't think that you'll be able to find this information in the 

>>literature (either in a library or on-line) anywhere else..  Take it (and 

>>use it as a benchmark/reference) or leave it...

>>

>>

>>...Joel Baumbaugh (baumbaug@nosc.mil)

>>     SSC-SD...

>>

>>

>>At 09:53 AM 2/18/2004 -0500, JDNUKE52@aol.com wrote:

>>>I have one question what was the LCS window settings and what liquid 

>>>scint cocktail use this is very important when establishing LCS efficiencies.

>>>

>>>

>>> 

>>>Thankyou

>>>

>>> 

>>>Jim Dykes  COH

>>>