Abstract Disclosed is an improved composite anode for rotating-anode xray tubes and an improved method of fabrication thereof. The anode comprises a substrate disk, a portion of whose focal track is scored, for example by scratching or engraving of one or more annular grooves of rectangular cross-section. A coating of x-ray emissive material covers the scored region. In certain embodiments of the invention, the emissive coating is undercoated with an interlayer of a material which is a poor emitter of xrays. The emissive coating and/or the undercoating may cover other portions of the disk and, in particular, may cover all exposed surfaces thereof. The method comprises providing such a disk, scoring it in the focal track region and applying an x-ray emissive coating to the scored region. The last step may be preceded by the application of an undercoating of a material which is a poor x-ray emitter. Either or both coatings may be applied to other surfaces of the disk.
Anode as in claim 1, wherein said coating comprises a material selected from the group consisting of tungsten and all alloys of tungsten and rhenium.
Claim 2
Dependent Claim
10 words
Anode as in claim 2, wherein said coating comprises tungsten.
Claim 3
Dependent Claim
15 words
Anode as in claim 1, wherein said scoring comprises at least one substantially annular groove.
Claim 4
Dependent Claim
26 words
Anode as in claim 4, wherein: said groove is substantially rectangular in a cross-section taken parallel to said axis; and said coating substantially fills said groove.
Claim 5
Dependent Claim
13 words
Anode as in claim 4, wherein a plurality of annular grooves is provided.
Claim 6
Dependent Claim
47 words
Anode as in claim 1, wherein said coating comprises a first, substantially non-x-ray emissive layer and a second, x-ray emissive layer: said first layer being in juxtaposition with substantially all exposed surfaces of said substrate disk; and said second layer being in juxtaposition with said first layer.
Claim 7
Dependent Claim
33 words
Anode as in claim 7, wherein said first material comprises carbon and said first layer comprises a material selected from the group consisting of: Niobium Carbide; Tantalum Carbide; Titanium Carbide; and Zirconium Carbide.
Claim 8
Dependent Claim
11 words
Anode as in claim 7, wherein: said second layer comprises Tungsten.
Claim 9
Dependent Claim
20 words
Anode as in claim 1 wherein said scoring comprises a groove which is substantially spiral with respect to said axis.
Claim 10
Dependent Claim
12 words
Anode as in claim 1 wherein said upper surface is substantially flat.