Re: P-32 LSC efficiency

[gu9@cosmail1.ctd.ornl.gov (Robert J. Gunter)]

Bill,

Just calculate the energy at which electrons exceed the speed of light in
water and compare it to the energy of the electrons you are considering.
Don't forget to account for relativistic effects.

Rob Gunter

At 02:17 PM 11/30/95 -0600, you wrote:
>Will someone confirm my thinking on this... or tell me where I'm wrong?	
>
>A known amount of P-32 is counted in 5ml of counting cocktail in a 
>Beckman liquid scintillation counter with channels wipe open.  There is 
>no chemi or photo luminesence.  A P-32 counting efficiency of about 150% 
>is shown.
>
>The efficiency exceeds 100% because Chenenkov effect contributes to the 
>counter cpm.  Right ....?  In what counting region might one find the 
>Cherenkov radiation appear?  ... H-3 region?, ... C-14 region?
>
>Thanks for the help,  Bill Fendt, 35346@udel.edu
>
>
Robert J. Gunter
CEDS Health Physicist
Ph: 6-6317
Bldg:  105MIT
MS:  6494