Estimation by Smearing of the Level of Tritium Surface Contamination

For the estimation of tritium surface contamination by a smear technique, some experiments have been made on the optimum content of glycerol loaded in the smear paper, the fraction of tritium removed by the paper from the surface contamination (i. e., removal efficiency), the counting efficiency for a 2π gas flow counter, and the desorption of tritium from contaminated smear papers.Of the total contamination, 1% and 10% can be removed using a 25w/o glycerol loaded smear paper from a permeable material such as synthetic polymer resin tile and a non-permeable one like stainless steel plate, respectively. The counting efficiency for a tritium smear sample is about 10% for the counter. It is therefore appropriate to assume that the overall counting efficiency in this method (removal efficiency multiplied by counting efficiency) is 0.1% and 1% for the above two materials, respectively. The desorption of tritium is much less from a glycerol loaded smear paper, being only 20% in 40min, while it is as high as 70% from the non-glycerol loaded one.