摘要:
An x-ray tube (20) includes an evacuated envelope (26). Mounted within the evacuated envelope are a cathode (23) and a rotatbly supported anode (30). A rotor (70) is included for rotatably driving the anode. The rotor (70) is electrically insulated from the anode (30) by a disk (76) comprised of an insulating material.
摘要:
An x-ray tube (20) comprising a cathode (23) and an anode (24) in operative relationship with the cathode (23). The anode (24) is mounted on a stem (32). The x-ray tube includes at least one bearing (58) rotatably receiving the stem (32). The at least one bearing (58) has an outer bearing race (66) in an outer race member, an inner bearing race (62) and a plurality of bearing members (64) operatively disposed between the inner and outer bearing races. The x-ray tube (20) also includes an evacuated envelope (78) which encloses the tube components and receives the outer race member of the at least one bearing (58) in thermally conductive contact along an inner surface (79).
摘要:
An x-ray tube includes an envelope defining an evacuated chamber in which an anode assembly is rotatably mounted to a bearing assembly and interacts with a cathode assembly for production of x-rays. The x-ray tube further includes a heat shield disposed in the envelope. The heat shield serves to reduce heat radiating from the anode assembly which is transferred to the bearing assembly or otherwise serves to insulate the bearing assembly from such radiated heat. The heat shield is brazed or otherwise bonded to the anode assembly and is comprised of a material having a low emissivity so that a minimum amount of heat radiates through the heat shield.
摘要:
An x-ray tube includes an envelope defining an evacuated chamber and having a window transmissive to x-rays. An anode assembly and a cathode assembly operate within the envelope to produce x-rays which travel through the window transmissive to x-rays towards a patient or subject under examination. A shield transmissive to x-rays is coupled to the envelope and positioned such that x-rays traveling through the window transmissive to x-rays must first travel through the shield. The shield prevents substantially all secondary electrons created during the production of x-rays from coming into contact with the window transmissive to x-rays thereby preventing excessive heating of the window transmissive to x-rays. An electrode defined by the envelope in a region proximate the window transmissive to x-rays may additionally or alternatively be used to prevent secondary electrons from reaching the window transmissive to x-rays.
摘要:
The present invention relates to X-ray tube technology in general. Most of the energy applied to the focal spot via electron bombardment is converted to heat; the generation of electromagnetic radiation may be considered to be quite inefficient. One of the central limitations of X-ray tubes is the cooling, thus the dissipation of heat, of the anode element, in particular the focal track. Consequently, an anode disk element that may sustain increased heat while still maintaining structural integrity and furthermore that may provide improved dissipation of heat from the focal track is presented. According to the present invention, an anode disk element (1), comprising an anisotropic thermal conductivity, for the generation of X-rays is provided. The anode disk element (1) comprises a focal track (4) and at least one heat dissipating element (5). The anode disk element (1) is rotatable about a rotational axis (6) with the focal track (4) being rotationally symmetrical to the rotational axis (6). The at least one heat dissipating element (5) is adapted for heat dissipation from the focal track (4) in the direction of reduced thermal conductivity of the anode disk element (1).
摘要:
A CT scanner includes a stationary gantry (10) defining an examination region (12) and a rotating gantry (16) which rotates about the examination region. At least two x-ray tubes (18a, 18b), each capable of producing a beam of radiation directed through the examination region, are mounted to the rotating gantry. The x-ray tubes are switchably connected to an electrical power supply (24). X-rays are detected by an arc of x-ray detectors (14) which generate signals indicative of the radiation received. These signals are processed by a reconstruction processor (32) into an image representation. A thermal calculator (60) estimates when an anode in one of the x-ray tubes (18) reaches a selected temperature. The thermal calculator (60) controls a switch (28) which is electrically connected between the x-ray tubes and the power supply. The switch selectively switches power from the power supply alternately to the x-ray tubes. Each time the thermal calculator estimates that the anode of one of the x-ray tubes has reached selected temperature, that tube is switched off and the other tube is switched on.
摘要:
A tomographic x-ray imaging system comprises a large plurality of parallel data acquisition channels which integrate and digitize signals from an array of x-ray detectors. Calibration pulses are injected into each data acquisition channel to permit measurement of drift in electronic gain and dc offset parameters. Separate x-ray detectors continuously monitor the intensity of the x-ray source.The measured values for channel gains, dc offsets, and source intensity are fed to a digital computer where they are automatically combined with x-ray transmission data to compensate for system drift and extend the period between calibration measurements.
摘要:
An anode disk element for the generation of X-rays that provides improved dissipation of heat from a focal track includes an anisotropic thermal conductivity. The anode disk element includes a focal track and at least one heat dissipating element. The anode disk element is rotatable about a rotational axis with the focal track being rotationally symmetrical to the rotational axis. The at least one heat dissipating element is configured for heat dissipation from the focal track in the direction of reduced thermal conductivity of the anode disk element.
摘要:
A rotating assembly 79 includes an anode assembly 55 coupled to a shaft 70 and a rotor 75 including a rotor body 77. The anode assembly 55 includes an elongated neck portion 58 and is rotated via the shaft 70 about an axis of rotation 65 in an x-ray tube 12. The shaft 70 is mounted by a straddle bearing assembly 68 having a bearing housing 100. The bearing housing 100 includes a first elongated portion 101 and second elongated portion 102, and a base portion 103. The first elongated portion 101 and the second elongated portion 102 each pass through a center of mass C of the rotating assembly 79 and define an cooling duct 119 for removing heat from the anode assembly 55 during operations. A first bearing 90a and a second bearing 90b are disposed in the bearing housing 100 on opposite sides of the center of mass C of the rotating assembly 79. The first bearing 90a and the second bearing 90b are received between inner races 82a, 82b defined by the shaft 70 and outer races 92a, 92b defined by an outer bearing member 94 adjacent the second elongated portion 102. The second bearing 90b is positioned such that it is always in a closer thermal conductive path to a peripheral edge of the anode assembly 55 than the first bearing 90a regardless of an amount of load of the rotating assembly 79 supported by the first or second bearing.
摘要:
An apparatus for triggering chemical augmented electrical fuses includes a light source which emits a light signal in the form of visible or infrared light energy upon receiving a signal from a control system, trigger signal source or other fuses. The light signal is coupled to a light detector by an optical coupling device such as a fiber optic cable. Upon receipt of the light signal, the light detector generates a signal which causes the application of electrical energy to exothermic material in a fuse, thereby detonating the material and causing interruption of current through the triggered fuse.