method for the analysis of the optical characteristic values of a local object, device for implementing the process and application of this process

摘要

1279019 Photo-electric testing COMMISSARIAT A L'ENERGIE ATOMIQUE 18 June 1969 [20 June 1968] 30893/69 Heading G1A In a method and apparatus for monitoring an optical characteristic of an article values detected during each scan of the article are compared with at least two reference values. The article, a radiograph of a uranium fuel element, is mounted on a reciprocating table to reciprocate beneath a detector head carrying its own light source, mounted on a lead-screw, and the radiograph includes two lines conveying the reference values which may be equivalent to the minimum and maximum uranium content to be tolerated, the lines having been produced on the radiograph by two aluminium strips whose thickness is such that their X-ray absorption is representative of these values. The scanning mechanism may be driven by a motor, or manually by a hand wheel, and the positions of the head relative to the radiograph are recorded on a chart. The instantaneous radiograph values are detected by a photo-multiplier and the reference values are developed on a pair of auxiliary photo-cells, the photo-multiplier having an electro-magnetically controlled shutter to obstruct the light beam if it becomes excessive. The reference values are stored and the instantaneous values detected by the photo-multiplier are separately compared with them to indicate on a record whether the value is between, above, or below the reference values. The reference values may also be detected by the photomultiplier. The arrangement eliminates errors arising in the preparation of the radiograph. The detector may respond to the refractive index of the article, and may be used to detect a line, or to obtain an average value in a desired zone by counting.