Appts. for X=ray examination with absorption filter - between source and object comprising 2 elements producing relatively low and high hardness increase in central area respectively

摘要

Appts. for X-ray examination of an object comprises an absorption filter (3) between the source (1) and the object to harmonise the spatial intensity distribution of the X-ray beam (5) after passing through the object. This filter consists of (at least) two separate filter elements (3a,b) pref. selected such that one (3b) produces a relatively small increase of the hardness (penetrating power) in the central area of the beam whilst the other (3a) produces a relatively large hardness increase in that area. The element (3b) may consist of Al2O3 with a thickness varying between 0 and 20 mm (bi-concave) whilst the other consists of Cu with a central thickness of 0.5 mm (bi-convex).