Abstract
The monitoring of the level of a constituent applied during processing is investigated by adding a tracer in which radioactivity is subsequently induced. This procedure eliminates any difficulties arising in processing plant from radioactive contamination. The principle is illustrated by application to the measurement of wax applied to woollen knitting yarn, in which antimony in the form of triphenyl stibine is used to trace paraffin wax. Measurement of the gamma radiation from Sb122 produced by pile-irradiation of yarn samples, allows the wax content on one-metre lengths to be estimated at the l% level with a coefficient of variation of 2·8%.