Radioactive Carbon Dioxide Counting by a Plastic Scintillator Cell
1966 Volume 15 Issue 6 Pages 295-300
Details
1966 Volume 15 Issue 6 Pages 295-300
A strong “memory” effect was found after the measurement of 14CO2 with a NE 102 plastic phosphor counting cell.
Experimental tests with thin NE 102 strips showed that the residual radioactivity was due to the absorption of 14CO2 into the plastic phosphor and desorption was diffusion controlled in the solid phase. A diffusion coefficient of 13.5×10-8cm2/sec was calculated from the experimental desorption data at 28°C.
A new counting cell was designed based on the diffusion data. The counting rates of nine separate samples prepared from the same specific activity source were able to be reproduced to ±0.35%.
This cell was successfully adapted to the counting of 14CO2 in a self diffusion study.
