Varian Medical Systems’ X-ray Products, headquartered in Salt Lake City, is an independent supplier of X-ray tubes for X-ray imaging. More than 400 different types of medical and industrial X-ray tubes are offered by Varian. Each type of X-ray tube requires testing that will ensure the desired outcome from the tube. Some major factors that contribute to the quality of the X-ray beam are the orientation of the cathode and the spacing between anode and cathode. In the development of new cathode head geometries and X-ray tubes, Varian’s current experimental process requires manual positional adjustments. Each time new adjustments are made, the vacuum must be removed, the adjustment made, and the vacuum reestablished. The process is both inaccurate and time consuming. Varian has asked BYU Capstone Team 29 to design and build a robust system that accurately and repeatedly positions an X-ray cathode head within a vacuum.

The system that the team generated consists of a purchased vacuum chamber access port called a mechanical feed-through, a gear box assembly, and a device to secure the cathode head. The mechanical feed-through transfers linear and rotary motion through the vacuum while maintaining the vacuum seal. The feed-through is attached to the gear assembly with a clamp. This whole assembly moves up and down with linear adjustments made by the feed-through. The cathode head is secured in a holder that is connected to the gear assembly. Its angle relative to the anode is adjusted with the rotary motion from the feed-through. The new design greatly increases the efficiency of Varian’s X-ray tube development process, because the development and design validation time has decreased for each X-ray tube assembly.