APERTURE SYSTEM FOR RADIATION SOURCES SITUATED IN PARALLEL PLANES

摘要

19.9.1979 PHD 78-148 "Aperture system for radiation sources situated in parallel planes". Aperture plates comprising fixed apertures are suitable to only a limited degree for multiple radiation sources. In order to enable stopping of the radiation beams of a multiple radiation source to the size of an object zone to be examined, use is made of aperture systems comprising aperture plates which are displaceable parallel to each other. The aperture plates comprise passages whose distribution corresponds to the distribution of the radiation souces. By lateral parallel displacement of the aperture plates, the passages are shifted with respect to each other, so that the passage can be adjusted.Continuously,adjustable apertures can thus be realized. When the radiation sources are situated in different mutually parallel planes, a group of aperture plates must be associated with each plane for continuous stopping of the radiation beams by means of the aperture plates. The dimensions of the passages of the aperture plates are then each time dependent of the position of the aperture plates in the beam path of the multiple radiation source.