Ring tube x-ray source

An x-ray generator comprising:

• a generally toroidal housing having an evacuated interior;
• an annular anode surface mounted in the toroidal housing interior, the anode surface being in thermal communication with a cooling fluid passage such that cooling fluid can be circulated contiguous to the anode surface for removing heat;
• a cathode assembly including:
• a cathode cup which holds a cathode filament which is heated by a current flowing therethrough to emit the electron beam;
• the cathode cup being mounted to a first electrical insulator;
• an annular ring on which the first insulator is supported;
• a motor means for rotating the annular ring;
• a means for magnetically levitating the annular ring within the toroidal housing;
• one end of the cathode filament being connected with the cathode cup and the other end of the cathode filament being connected with a secondary winding extending around a portion of the first electrical insulator;
• an electrical connector extending through the first electrical insulator from the cathode cup to a means which is biased to the cathode potential, the secondary winding being connected with the electrical connector;
• a second electrical insulator surrounding the secondary winding;
• and
• a primary winding wound around the second electrical insulator, such that the primary winding is isolated from the secondary winding, the primary winding being connected with a means for controlling current flow through the cathode filament, whereby the means for controlling current flow through the cathode filament is isolated therefrom.

An x-ray generator comprising:

• a generally toroidal housing having an evacuated interior and an annular x-ray permeable window;
• an annular anode surface mounted in the toroidal housing interior, the anode surface being in thermal communication with a cooling fluid passage such that cooling fluid can be circulated contiguous to the anode surface for removing heat;
• a cathode assembly rotatably received in the toroidal housing, the cathode assembly including:
• an annular ring rotatably received in the toroidal housing evacuated interior, the annular ring having a smaller diameter surface toward a center of the toroidal housing, a larger diameter surface opposite to the smaller diameter surface, and a pair of oppositely disposed side edges,
• an active magnetic levitation bearing means including (i) annular permanent magnet rings mounted to the annular ring along each of the smaller diameter surface, the larger diameter surface, the pair of both side edges, (ii) a permanent magnet ring mounted to the toroidal housing adjacent the permanent magnet ring mounted to one of the larger and smaller diameter surfaces and the permanent magnets mounted to one of the side edges, and (iii) a first controllable electromagnetic ring stationarily mounted to the toroidal housing adjacent the permanent magnet mounted to the other of the larger and smaller diameter surfaces and a second controllable electromagnetic ring mounted to the toroidal housing adjacent the permanent magnet ring mounted to the other side edge,
• at least one electron beam generating means mounted to the annular ring for rotation therewith;
• a means for transferring a filament current from a filament current source exterior to the toroidal housing to the electron beam generating means mounted to the rotatable annular ring in the toroidal housing;
• a large diameter induction motor having a stator mounted to the toroidal housing and a rotor connected with the annular ring for rotating the annular ring and the electron beam generating means within the toroidal housing.

An x-ray generator comprising:

• a generally toroidal housing having an evacuated interior;
• an annular anode surface mounted in the toroidal housing interior, the anode surface being in thermal communication with a cooling fluid passage such that cooling fluid can be circulated contiguous to the anode surface for removing heat;
• a cathode assembly mounted on an annular surface disposed within the toroidal housing including a means for emitting electrons to form an electron beam that strikes the anode surface;
• an annular rotating capacitor plate mounted to the annular ring in a capacitively coupled relationship to a stationary capacitor plate mounted to the housing, the rotating capacitor plate being connected with the electron emitting means for controlling electrical power thereto and the stationary cathode plate being connected with an AC power source;
• a means for moving the electron beam to at least a multiplicity of points around the anode surface.

An x-ray generator comprising:

• a generally toroidal housing having an evacuated interior and an annular x-ray permeable window facing a central axis of the toroidal housing;
• an annular anode surface mounted in the toroidal housing interior, the anode surface being in thermal communication with a cooling fluid passage such that cooling fluid can be circulated contiguous to the anode surface for removing heat;
• a cathode assembly including;
• an annular ring rotatably disposed within the evacuated interior of the toroidal housing and centered around the central axis,
• a means for emitting electrons in the form of an electron beam that strikes the anode surface, the electron emitting means being mounted to the annular ring,
• an annular secondary transformer winding mounted to the annular ring and centered around the central axis, the annular secondary transformer winding being connected with the electron emitting means for providing a filament current thereto;
• an annular primary transformer winding mounted to the toroidal housing adjacent the annular secondary transformer winding such that electrical current is selectively transferred therebetween;
• a means for rotating the annular ring within the evacuated interior of the toroidal housing.

An x-ray generator comprising:

• a generally toroidal housing having an evacuated interior;
• an annular anode surface mounted in the toroidal housing interior, the anode surface being in thermal communication with a cooling fluid passage such that cooling fluid can be circulated contiguous to the anode surface for removing heat;
• a cathode assembly mounted on an annular ring rotatably disposed within the toroidal housing including:
• a means for emitting electrons to form an electron beam that strikes the anode surface,
• a supporting means mounted to the annular ring adjacent the electron emitting means, the supporting means supporting at least one of an off-focal radiation collimator means and a filter means for filtering the x-ray beam, the supporting means supporting the collimator means and the filter means closely adjacent the anode means such that the filter means and the collimating means rotate with the electron beam;
• a means for rotating the annular ring such that the electron beam rotates to at least a multiplicity of points around the anode surface.

An x-ray generator comprising:

• a generally toroidal housing constructed primarily of metal, the housing having an evacuated interior;
• an annular metal anode surface mounted in the toroidal housing interior in electrical communication therewith such that the anode surface and the toroidal housing are in substantial electrical potential equilibrium with each other, the anode surface being in thermal communication with a cooling fluid passage such that the cooling fluid can be circulated contiguous to the anode surface for removing heat;
• a cathode assembly rotatably received in the evacuated interior of the toroidal housing, the cathode assembly including a cathode cup which emits electrons to form an electron beam that strikes the anode surface in response to receiving a filament current;
• a means for establishing a large potential difference between the cathode cup and the anode surface;
• an isolation transformer mounted to the cathode assembly, the isolation transformer including a secondary winding connected with the cathode cup and maintained substantially at the potential thereof and a primary winding which is maintained substantially at the potential of the housing, the primary winding being connected with a means for transferring heating current from the toroidal housing to the rotating cathode assembly;
• a means for rotating the cathode assembly within the evacuated interior of the generally toroidal housing.

An x-ray tube comprising:

• a generally toroidal housing having an evacuated interior;
• an annular anode surface mounted in the toroidal housing interior, the anode surface being in thermal communication with a cooling fluid passage such that cooling fluid can be circulated contiguous to the anode surface for removing heat;
• a cathode assembly including:
• an annular ring rotatably disposed within the toroidal housing,
• a plurality of electron emitting means for emitting electrons to form an electron beam that strikes the anode surface, the electron emitting means being supported by the annular ring;
• a coupling means for selectively coupling the electron emitting means with an exterior current supply;
• and,
• a switching means supported by the annular ring for selectively switching supplied current among the electron emitting means;
• a means for rotating the annular ring.

An x-ray generator comprising:

• a generally toroidal housing constructed primarily of metal, the housing having an evacuated interior;
• an annular metal anode surface mounted in the toroidal housing interior in electrical communication therewith such that the anode surface and the toroidal housing are in substantial electrical potential equilibrium with each other, the anode surface being in thermal communication with a cooling fluid passage such that the cooling fluid can be circulated contiguous to the anode surface for removing heat;
• a cathode assembly including:
• an annular ring rotatably received in the evacuated interior of the toroidal housing, the rotatable ring including an electrically conductive portion and an electrically insulating portion,
• a cathode cup means for emitting electrons to form an electron beam that strikes the anode surface, the cathode cup means being mounted to the electrically conductive portion of the annular ring such that the electrically conductive portion and the cathode cup means are substantially in electrical potential equilibrium,
• a magnetic levitation bearing means mounted to the electrically insulating portion of the annular ring and to the toroidal housing such that the magnetic levitation bearing means and the toroidal housing are maintained substantially in electrical equilibrium with each other;
• a means for maintaining a large electrical potential difference between the cathode cup and the toroidal housing;
• a means for rotating the annular ring within the evacuated interior of the toroidal housing.

An x-ray generator comprising:

• a generally toroidal housing having an evacuated interior;
• an annular anode surface mounted in the toroidal housing interior, the anode surface being in thermal communication with a cooling fluid passage such that cooling fluid can be circulated contiguous to the anode surface for removing heat;
• a cathode assembly including:
• an annular ring rotatably received in the evacuated interior of the housing;
• a means for emitting electrons to form an electron beam that strikes the anode surface the electron emitting means being mounted to the annular ring;
• a high voltage biasing means for biasing the cathode assembly to a high negative voltage relative to the housing, the high voltage biasing means including at least one hot cathode supported by the housing and a partially toroidal electron receiving plate at least partially encompassing the hot cathode and supported by the annular ring such that the toroidal plate remains closely adjacent to the hot cathode as the annular ring rotates;
• a means for rotating the annular ring around the evacuated interior of the housing.

An x-ray tube comprising:

• a generally toroidal housing having an evacuated interior;
• an annular anode surface mounted in the toroidal housing interior, the anode surface being in thermal communication with a cooling fluid passage such that cooling fluid can be circulated contiguous to the anode surface for removing heat;
• a cathode assembly disposed within the toroidal housing including:
• an annular ring rotatably disposed within the housing,
• a means for emitting electrons to form an electron beam that strikes the anode surface;
• a means for rotating the annular ring within the toroidal housing;
• a position encoder for providing an encoded signal indicative of an angular position of the annular ring relative to the housing.

An x-ray tube comprising:

• a generally toroidal housing having an evacuated interior;
• an annular anode surface mounted in the toroidal housing interior, the anode surface being in thermal communication with a cooling fluid passage such that cooling fluid can be circulated contiguous to the anode surface for removing heat;
• a cathode assembly including;
• a means for emitting electrons to form an electron beam that strikes the anode surface, the electron emitting means rotatably disposed within the toroidal housing,
• a means for supporting at least one of a collimator and a filter mounted adjacent the electron emitting means for rotation therewith;
• a means for rotating the electron emitting means within the toroidal housing.

An x-ray tube comprising:

• a generally toroidal housing having an evacuated interior;
• a first annular anode surface mounted in the toroidal housing interior, the first anode surface being in thermal communication with a first cooling fluid passage such that cooling fluid can be circulated contiguous to the first anode surface for removing heat;
• a second anode surface mounted in the toroidal housing interior in thermal communication with a second cooling fluid passage;
• a cathode assembly disposed within the toroidal housing including:
• a first means for emitting electrons to form a first electron beam that strikes the first anode surface;
• a second means for emitting electrons mounted on the cathode assembly for selectively forming a second electron beam which strikes the second anode surface;
• a means for moving the first and second electron beams to a multiplicity of points around the first and second anode surfaces.