Horace, > >...Anyway if lots of tritium was being > >produced, a fair amount of the bremsstrahlung gamma photons > >of about 3-6 keV would be seen.
> These gamms have almost no pentrating power in water. This is why organic > solvents are used for liquid scintillation counting. The water is kept to > a few percent in the counting vials. First, I understand the point about boil-off calorimetry, but this is hardly news. People have been issuing similar warnings for some time. However, once again I think you may be missing the obvious. IF (big if) tritium were being produced, then you would not necessarily be comparing Tl 80 keV gammas against almost undetectable tritium gammas. This is because some of the tritium begins to outgas immediately and then can shed 20 keV radiation directly into the monitor, whereas all of the Tl (which is still immobilized in the water) would have its gamma output attenuated. So you see, to really get down to brass tacks one needs to know how these reading were taken and what the raw data showed, or else assume (as I will now do) that the experimenter knew that tritium "could" possibly be present and took all the necessary precautions to eliminate any possibility of a tritium signal. I see from the post just now from Peter that his condenser was water cooled, but I must assume that the Tl did not cross the pyrex glass boundary or else he would have mentioned it specifically. Jones
