tube arcing

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Tube arcing occurs when there is a short-circuit within the tube, typically from the cathode to the tube envelope. The result is a temporary loss of x-ray output and a localized artefact.

A number of causes of tube arcing are recognized :

  • insulator surface flashover
  • insulator breakdown
  • vacuum flashover
    • most common
    • due to particulate impurities or gas within the tube
    • new tubes are more prone to this problem due to residual gas

    • A small amount of tube arching is not uncommon and modern scanners have automated processes to remove the artefact from the final images .