Radiographic apparatus

Raytheon Company, U.S.A. have patented an on-line electronic system of normalising the responses from the photomultiplier tubes used in conjunction with a scintillator in an X-ray radiographic camera. A problem with present cameras is that the individual photomultipliers have different intensity responses which also change in time with respect to each other. The individual responses of each photomultiplier tube are measured with a uniform sheet of radioactive material in front of the camera. The associated electronic equipment then calculates scaling factors which give all photomultiplier tubes an identical response and then places these factors in an addressable store. The store is then addressed in an on-line mode to produce a visual display of the transmitted X-rays. (U.K.)