instruments

["Robert R. Milwicz" <milwicz@arundel.Princeton.EDU>]

Please respond to e-mail directly to me. The questions I needs 
answers to relate to beta counting, non-scintillation method.

Background Information

Our Tennelec 5100 low background beta counter has suddenly failed.
We are sending parts back to the company for repair cost estimates. This is the 
situation that was raised as a result of that failure.

To justify the cost of repair (if significant) or replacement of this counter,  
I need to justify its use. We have a liquid scintillation counter and the 
question that was posed is this. If we have a scintillation counter 
why do we need a beta counter to count the same isotopes (normally 
wipes taken during lab smear surveys)? Why not use the liguid scintillation 
counter only?

My reasons are that it is easier to count in the Tennelec, there is 
no liguid scintillation cocktail to dispense and dispose of and no vial
waste generated and it takes less time to prepare samples for counting.
There is no chemiluninescence effect or quenckhing to worry about and it costs 
less per sample. 
Since most of the labs use P-32 and S-35 and not H-3 which requires 
scintillation counting why count in LSC. 

I would like to hear from you.

What do you use to count your routine 
smears? LSC or beta counting?

Do you have both types of instrumentation?

If you have both types of instruments available and your low 
background beta counter failed, would you get it fixed? Buy a new 
one if the old one could not be fixed?

I really would appreciate an answer.

BOB Milwicz
milwicz@princeton.edu