A highly accurate focal spot camera--laboratory and field model.

A device has been developed to determine accurately and quickly the shape, size, and intensity distribution of an x-ray tube focal spot. The pinhole device weighs only 1 kg and is portable, enabling it to be used either as a field unit or in a laboratory. The special design obviates any risk of irradiation danger to the investigator, or thermal overloading of the x-ray tube under investigation. The degree of accuracy with which the central beam can be located is better than +/-250 micron, well beyond the requirements of the latest NEMA standards regarding dimensional measurements of diagnostic x-ray tube focal spots. A star test pattern picture may be taken instead of the pinhole picture if required. The device is described and areas of application are discussed.