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US 4,969,173 AGranted
X-ray tube comprising an annular focus
AssigneeU.S. Philips Corporation
InventorLourens Valkonet
Life of this patent
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Abstract
The electron-emissive element in an X-ray tube is constructed so as to be loop-shaped so that an electron target which is also loop-shaped can be formed on an anode. Notably for target transmission tubes having an integrated window-anode element, a substantial reduction of the window temperature can thus be achieved. Inter alia because of the lower temperature gradients, the window can be constructed to be thinner; however, its service life is substantially prolonged and the radiation efficiency of the tube is increased.
Claims5
An x-ray tube comprising an envelope;
- a window through which x-rays produced inside the envelope are transmitted to the exterior of the envelope;
- and cooling means for transferring heat away from said window during operation of the tube;
- said envelope containing:
- a. an x-ray producing anode layer disposed on a surface of the window, said layer being optimally positioned to effect heat transfer to said cooling means;
- b. a loop-shaped electron-emitting cathode disposed for emitting electrons toward the anode layer;
- and
- c. electrode means disposed adjacent the cathode for focusing electrons emitted by the cathode into an annulus of controllable width on the anode layer.
4 more elements
Dependencies are inferred from the claim text.