Abstract: An X-ray fluorescence thickness measuring devise includes a primary X-ray beam collimation and workpiece positioning system that markedly increases the detectable fluorescent X-radiation from diverse specimen calibration standards and workpieces subjected to measurement. The positioning system includes an optical viewing system that provides a video signal image of the specimen surface prior to and during specimen radiation without hazard to the unit operator and independent of the collimator bore selected. A further feature of the measuring device is that it includes a system which assures repetitive and accurate positioning of a selected collimator relative to the axis of the X-ray beam to obtain maximum beam transmission therethrough.

Abstract: Improved calibration standard construction for X-ray fluorescence thickness measurement gauges formed of one or more plated layers of known character and thickness disposed on an apertured supporting foil base and accessible to X-radiation through an aperture at the base of a conically shaped bore in a surrounding protective housing member.