[ RadSafe ] Background from Static Electricity in Tritium counters
parthasarathy k s
ksparth at yahoo.co.uk
Tue Dec 27 18:27:16 CST 2005
I found that I did not mark a copy of my response to all. Since it may be of interest to all handling liquid scintillation counters let me mark a copy for all.
"A research group in a University in India, while carrying out study of photosynthesis using plankton grown in an atmosphere CO2 labelled with C-14, experienced serious background fluctuations. Some of the amateurs inthe group felt that they discovered some new effect. They were getting more counts than what was estmated from the activity in the sample!
It took some time for them to identify the source. Plankton exposed to light glows for some time. The erratic background got stabilized after they kept the samples to be counted in the light tight liquid scintillation counter for a few days!
Don Jordan <DonJordan at ramservicesinc.com> wrote:
Using natural latex gloves causes a lot of static problems. Switching to
nitrile gloves will solve the problem. I believe that vinyl gloves also do
not cause static, but I have not used them. The fabric softener wipes will
eventually deposit a lot of crud in your scintillation counter.
My experience with static is that one gets very erratic counts. In one
count you'll get 10,000 counts, the next one will be a few hundred, and the
one after that will be 20,000. The problem you describe sounds more like
chemiluminescence, except for the increase when you remove a vial from the
counter. This sounds more like phosphorescence caused by fluorescent lights
or direct sunlight.
RAM Services, Inc.
510 County Highway V
Two Rivers, WI 54241
DonJordan at ramservicesinc.com
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