Method of fast current modulation in an X-ray tube and apparatus for implementing same

A method of fabricating a cathode assembly, the method comprising:

• attaching a filament to a cathode cup;
• forming a one-dimensional grid having crosspieces that extend generally along a width direction of the filament, wherein forming the one-dimensional grid comprises one of:
• forming a wire into a zig-zag pattern to form each of the crosspieces, wherein the wire comprises two ends, each end of the wire attached to a respective attachment point;
• or
• forming a plurality of coil rings, each coil ring of the plurality of coil rings forming a respective crosspiece of the plurality of crosspieces;
• or
• providing a first support beam and a second support beam, fixedly attaching first ends of the crosspieces to the first support beam, and slideably capturing second ends of the crosspieces in slots in the second beam;
• positioning the grid proximately to the filament such that electrons that emit from the filament pass between the crosspieces of the one-dimensional grid when accelerated toward an anode;
• and
• attaching the grid to the cathode cup at attachment points such that the crosspieces expand, when heated, relative to the attachment points without distorting with respect to neighboring crosspieces.

A method of fabricating a cathode assembly, the method comprising:

• attaching a filament to a cathode cup;
• forming a one-dimensional grid having crosspieces that extend generally along a width direction of the filament, wherein forming the one-dimensional grid comprises:
• providing a first support beam and a second support beam;
• and one of
• fixedly attaching first ends of the crosspieces to the first support beam and springably attaching second ends of the crosspieces to the second beam;
• or
• flexibly attaching first ends of the crosspieces to the first support beam and fixedly attaching second ends of the crosspieces to the second beam;
• positioning the grid proximately to the filament such that electrons that emit from the filament pass between the crosspieces of the one-dimensional grid when accelerated toward an anode;
• and
• attaching the grid to the cathode cup at attachment points such that the crosspieces expand, when heated, relative to the attachment points without distorting with respect to neighboring crosspieces.

An x-ray tube comprising:

• a target configured to emit electrons from a focal spot;
• a cup;
• an emitter attached to the cup and positioned to emit high-energy electrons toward the focal spot;
• and
• a uni-dimensional grated mesh positioned proximately to the emitter and between the target and the emitter such that emitted electrons pass between rungs of the mesh, wherein the uni-dimensional grated mesh comprises a coil and wherein the emitter is positioned within the coil;
• wherein the uni-dimensional grated mesh is fixedly attached to the cup at attachment points such that rungs of the mesh expand and contract, upon heating and cooling, without substantial distortion with respect to the cup.

An x-ray tube comprising:

• a target configured to emit electrons from a focal spot;
• a cup;
• an emitter attached to the cup and positioned to emit high-energy electrons toward the focal spot;
• and
• a uni-dimensional grated mesh positioned proximately to the emitter and between the target and the emitter such that emitted electrons pass between rungs of the mesh, the uni-dimensional grated mesh being fixedly attached to the cup at attachment points such that rungs of the mesh expand and contract, upon heating and cooling, without substantial distortion with respect to the cup;
• and
• a pair of mounting beams, wherein each of the rungs comprises at least one end flexibly, slidably or springably attached to a respective one of the mounting beams such that the rungs are allowed to expand and contract relative to the one or more attachment points without substantial distortion with respect to the emitter.