Ring tube x-ray source with active vacuum pumping

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 circulated cooling fluid passage such that the cooling fluid removes heat from the anode surface;
• an annular rotor rotatably disposed within the housing interior;
• at least one cathode assembly mounted to the rotor for rotation therewith, the cathode assembly including a cathode for emitting electrons to form an electron beam that strikes the anode surface to generate an x-ray beam;
• a means for rotating the annular rotor such that electron beam is rotated around the anode surface;
• an active vacuum pump hermetically sealed into the housing interior with no exhaust for discharging atoms evacuated form the interior region, the active vacuum pump actively maintaining a vacuum of at least 10.sup.-6 Torr in the housing interior.

An x-ray tube comprising:

• a generally toroidal housing defining a vacuum region therein;
• an annular anode surface mounted in the toroidal housing vacuum region, the anode surface being in thermal communication with a circulated cooling fluid passage such that the cooling fluid removes heat from the anode surface;
• a rotor rotatably disposed within the vacuum region;
• at least one magnetic levitation bearing supporting the rotatable anode, the magnetic levitation bearing including:
• rings of a ferrous material mounted to the rotor along an inner diameter thereof within the vacuum region and a ring of permanent and electromagnetic coils disposed radially inward from and closely adjacent to the rings of ferrous material;
• and
• a magnetic window which seals at least the electromagnetic coils from the vacuum region while permitting magnetic fields therefrom to pass therethrough to interact with the ferrous rings;
• at least one cathode assembly mounted to the rotor for rotation therewith, the cathode assembly emitting electrons to form an electron beam that strikes the anode surface to generate an x-ray beam, the electron beam being rotated around the anode surface as the rotor rotates within the vacuum region;
• an active vacuum pump connected to the vacuum region for actively maintaining a vacuum of at least 10.sup.-6 Torr therein.

An x-ray tube comprising:

• a generally toroidal housing having an evacuated interior;
• a means for dividing the interior of the toroidal housing into at least a higher vacuum region and a lower vacuum region;
• an annular anode surface mounted in the toroidal housing interior higher vacuum region, the anode surface being in thermal communication with a circulated cooling fluid passage such that the cooling fluid removes heat from the anode surface;
• a rotor rotatably disposed within the interior of the toroidal housing;
• at least one cathode assembly mounted to the rotor for rotation therewith, the cathode assembly including a cathode for emitting electrons to form an electron beam that traverses the higher vacuum region and strikes the anode surface to generate an x-ray beam;
• a means for rotating the annular rotor such that electron beam is rotated around the anode surface;
• an active vacuum pump connected to the housing interior for actively maintaining a vacuum of at least 10.sup.-6 Torr in the higher vacuum region.

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 circulated cooling fluid passage such that the cooling fluid removes heat from the anode surface;
• an annular rotor rotatably mounted within the housing interior;
• at least one cathode assembly mounted to the rotor for rotation therewith, the cathode assembly including a cathode for emitting electrons to form an electron beam that strikes the anode surface to generate an x-ray beam such that the electron beam is rotated around the anode surface as the annular rotor rotates;
• an insulating means for electrically insulating the cathode assembly from the rotor such that the cathode assembly is maintainable at a different potential from the rotor;
• a means for maintaining the cathode assembly at a potential of at least -100 keV relative to the rotor;
• an active vacuum pump connected to the housing interior for actively maintaining a vacuum of at least 10.sup.-6 Torr therein.

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 circulated cooling fluid passage such that the cooling fluid removes heat from the anode surface;
• a rotor rotatably disposed within an interior of the toroidal housing;
• at least one cathode assembly mounted to the rotor for rotation therewith, the cathode assembly including a means for emitting electrons to form an electron beam that strikes the anode surface to generate an x-ray beam;
• an insulating means for electrically insulating the cathode assembly from the rotor;
• a means for maintaining the cathode assembly at a high negative potential of at least -100 keV relative to the rotor;
• a means for transferring a filament current across the vacuum region to the rotor;
• an isolation transformer connected between the filament current transferring means and the cathode filament to maintain the cathode filament at the high negative potential relative to the means for transferring the filament current;
• an active vacuum pumping means connected to the housing interior for actively maintaining a vacuum of at least 10.sup.-6 Torr therein.

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 circulated cooling fluid passage such that the cooling fluid removes heat from the anode surface;
• an annular rotor rotatably disposed within the interior of the toroidal housing;
• at least one cathode assembly mounted to the rotor for rotation therewith, the cathode assembly including a cathode that emits electrons to form an electron beam that strikes the anode surface to generate an x-ray beam, the electron beam being rotated around the anode surface as the rotor rotates within the housing interior;
• an x-ray beam collimator mounted to the rotor, within the evacuated interior of the housing, and adjacent the cathode assembly for rotation therewith, the collimator including a first pair of collimator walls for defining a thickness of the x-ray beam and a second pair of collimator walls for defining a fan angle of the x-ray beam;
• an active vacuum pump connected to the housing interior for actively maintaining a vacuum of at least 10.sup.-6 Torr therein.

An x-ray tube comprising:

• a generally toroidal housing having an evacuated interior, the housing including a plurality of sections which are clamped together with elastomeric gaskets therebetween for maintaining a vacuum within the housing;
• an annular anode surface mounted in the toroidal housing interior, the anode surface being in thermal communication with a circulated cooling fluid passage such that the cooling fluid removes heat from the anode surface;
• a rotor rotatably disposed within the housing interior;
• at least one cathode mounted to the rotor for rotation therewith, the cathode emitting electrons to form an electron beam that strikes the anode surface to generate an x-ray beam, the electron beam being rotated around the anode surface with the rotor;
• an active vacuum pumping means connected to the housing interior for actively maintaining a vacuum of at least 10.sup.-6 Torr therein, the active vacuum pumping means removing outgassing vapors from the elastomeric gaskets.