Abstract
A method is described in detail for the determination of radioactive hydrogen in a proportional gas counter. The conditions for the best operation of the counter are described. The apparatus, which has been in use for eight years, is easy to operate and requires very little maintenance.
The gas filling for the counter is produced by the reaction of ` active ' water on aluminium carbide in a simple metal vessel, and this is extended to the assay of tritium in labelled compounds, by a procedure consisting of a preliminary combustion in a high pressure oxygen bomb followed by the reaction of the water produced with aluminium carbide. The whole procedure takes less than one hour, and any required number of samples can be prepared at the same time.
The method is accurate to at least ±1% over the range of activities 20 to 104 µµc.