RE: Puzzler: How Does Humidity Affect Counting Efficiency?

[John_Sukosky@DOM.COM]

Wow, thanks for all the excellent replies to this instrument enigma.  Very

insightful and helpful in getting closer to a solution.



Since one possible solution is focusing on input voltage, here's some

additional data:



Instrument   Input Voltage Conditioner

Tri-Carb     SOLA

Tennelec     SOLA

HPGe         UPS



We also have a SAC-4 (ZnS alpha counter) in this Lab that we performance

check using an Am-241 check source.  The SAC-4 is on a "Line Conditioner",

and alpha source checks show no correlation with humidity (no problems

going above warning (2-sigma) or action (3-sigma) levels).



We also checked with our sister station, North Anna, to see if they had

experienced similar problems with any of their equipment.  Found out that

they have a problem similar to our Tennelec, with their G-5000.  G-5000

Alpha source checks have started trending higher in the last few months

(going into warning and control levels).  G-5000 Beta source checks have

remained steady and satisfactory.



We have the vendor service rep coming in today to look at our Tri-Carb.

I'll show him the data along with and the Radsafe insights and solutions.

I'll let everyone know what happens.



Thanks again for the all the replies, both on and off the list, and even

with phone calls.  This is just one example of the world-classs excellence

that Radsafe brings to our Rad Protection programs!





John M. Sukosky, CHP

Dominion

Surry Power Station

(757)-365-2594 (Tieline: 8-798-2594)



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