| 摘要 |
<p>An apparatus for measuring the weight, thickness or composition of a coating or coatings applied to a substrate includes a primary radiation source (11), a detector means (10), and means (6) for processing radiation reflected by the coating or coatings. The source of primary radiation delivers an output which is applied to the coating or coatings and the detector means (10) receives the reflected secondary radiation, the detector means (10) including at least two energy-sensitive or energy-dependent detectors comprising ionisation chambers (12, 13) fitted with energy-sensitive radiation filters (14, 15) able to differentiate between different elements of the coating or coatings from one another, the outputs of the chambers (12, 13) being processed by the processing means to provide an indication of the weight or thickness of the or each coating irrespective of composition, or of the composition of the coating or coatings. The filters (14, 15) are preferably absorption-edge filters and the source of primary radiation (11) may be either an X-ray generator or a radio-isotope producing Gamma radiation. The absorption of the radiation filters (14, 15) fitted to the ionisation chambers (12, 13) is selected so as to pass the reflected secondary radiation in accordance with the materials being subjected to the primary radiation from the source (11).</p> |
