Abstract: An assembly for measuring a trench depth parameter of a workpiece is disclosed. The assembly has an ultra-violet radiation source; a split fiber bundle having a first branch for propagating the ultra-violet radiation from the radiation source to a lens, and a second branch; a lens for focusing the UV radiation to the workpiece and refocusing an ultra-violet interference signal to the second branch; and a detector responsive to the ultra-violet interference signal received through the second branch. The detector transforms the ultra-violet interference signal to an electrical signal which is a measure of a trench depth of the workpiece. The ultra-violet interference signal is developed when ultra-violet radiation propagates through the workpiece and reflects from its base region to thereby interfere with ultra-violet radiation that is directly reflected by a workpiece surface which is different from the base region.

Abstract: The present invention is directed to an analytic method for detecting trace elements in fluid solution. A cation exchange resin is packed with a radiolabelled exchange material having certain characteristics and replaces the trace element ions in the fluid which becomes labelled. The label is subsequently detected using sensitive and well known radiation detection methods.