DETERMINATION OF X-RAY TUBE FOCAL SPOT POSITION

In x-ray spectral measurement using a semiconductor detector system, a ccurate positioning of the detector in front of the anode is very impo rtant. This needs accurate determination of the focal spot position on the target in an x-ray tube. We present a simple technique to determi ne the focal spot position accurately. Using a pinhole technique, the focal image made by x rays is overlapped on the target image made by v isible rays emitted when filament heating takes places. Both images ar e made in the same geometry with the tube diaphragm and filter removed .