Patent ID: 7416335

Claim:
A method for the design of an x-ray tube passively shielded from an externally applied magnetic field, comprising: (a) selecting magnetically permeable materials suitable for the design of at least two of the group of x-ray tube components consisting of an x-ray tube insert frame, an x-ray tube housing, an x-ray tube external shield envelope, an x-ray tube port, and an x-ray tube scatter cone; and (b) combining the x-ray tube components of step (a) with x-ray tube components made of non-permeable materials to obtain an x-ray tube that shields the space between an insert cathode and an insert anode from an externally applied magnetic field, and (c) determining the maximum acceptable magnetic field within the x-ray tube insert; (d) determining the maximum externally applied magnetic field magnitude; and (e) determining the maximum shielded tube weight; whereby the x-ray tube design meets the weight constraints of step (e) and the reduced field within the insert frame is less than the maximum of step (c) when the x-ray tube is subjected to an externally applied field of magnitude less than that of the maximum of step (d).