Abstract: 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.

Abstract: 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).

Abstract: An x-ray tube assembly (16) includes a housing (40) and an insert frame (54) supported within the housing (40), such that the insert frame (54) defines a substantially evacuated envelope in which a cathode assembly (60) and a rotating anode assembly (58) operate to produce x-rays. The rotating anode assembly (58) includes an anode target plate (64) coupled to a rotor (66) and bearing shaft (82), which is rotatably supported within a bearing housing (84), by a plurality of ball bearings (86). A heat barrier (90) substantially surrounds the bearing housing (84) and is coupled, along with the bearing housing (84) to an anode cold plate (100). The anode cold plate (100) includes a grooved cover (102), a basin (110), and a plurality of corrugated fins (120) disposed therein. Coupling both the bearing housing (84) and the heat barrier (90) to the anode cold plate (100) provides an effective means for cooling the bearing assembly (80).

Abstract: 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.

Abstract: A cooling oil circuit (D) circulates cooling oil over an x-ray tube absorbing its waste heat. A refrigeration circuit (E) then cools the cooling oil. A heat buffer (52) absorbing peak heat loads from the cooling fluid when the x-ray tube is generating x-rays. Valves (58, 60) regulate a relative amount of cooling oil entering the heat buffer to increase heat transfer efficiency. The heat buffer enables the system to handle peak heat loads with a smaller, more condensed refrigeration system, by absorbing heat during operation of the x-ray tube and releasing heat between operations.

Abstract: A high energy x-ray tube includes an evacuated chamber (12) containing a rotor (34) which rotates an anode (10) through a stream of electrons (A) in order to generate an x-ray beam (B). The rotor includes a bearing assembly (C) having a hollow bearing shaft (52) centrally aligned with a longitudinal axis (Z) of the rotor. The bearing shaft includes an interior annular wall (54) having an inner surface which defines a central bore (58). The bearing shaft has an outer surface (60), which with an inner surface of the bearing shaft, defines an annular chamber (62). An opening (64) is provided at the forward end of the annular wall to provide access from the central bore to the annular chamber. During exhaust processing, baking cycles, and normal operation of the x-ray tube, a pump (104) forces a cooling medium through the central bore, through the opening of the annular wall, and into the annular chamber. The cooling medium exits through channels (66).

Abstract: 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).

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: Each bearing of an aligned line-shaft has vibration responses which differ from the vibration responses of a misaligned system in which at least one of the bearings is statically displa=ced. Computed static displacement values for each bearing are derived from the equation of motion of the system employing mass, stiffness and damping coefficients of the system. The static displacement value of each bearing is computed from the vibration responses of all of the bearings. Accelerometers sense the vibration response of each bearing. A computer computes the magnitude of misalignment of each bearing from the sensed responses. The computed results provide an indication of the magnitude of static displacement of each bearing of the system causing the sensed vibration response.

Abstract: A method and apparatus for protecting switching elements, and in particular, thyristor switching elements, which are used to supply pulses to a capacitive load, from damage resulting from sparkover occurring in that load are described. The load voltage pulse is characterized by a period of rising voltage followed by a period of falling voltage, these two periods being separated by a transition period of maximum vulnerability of the switching element to damage from sparkover. Specifically, during this period of maximum vulnerability of the switching elments to damage, a gate trigger pulse is applied to the elements to cause them to resume a conductive state, independent of the occurrence of an abnormal sparkover condition.

Abstract: A method and apparatus for protecting switching elements, and in particular, thyristor switching elements, which are used to supply pulses to a capacitive load, from damage resulting from false triggering signals, i.e., triggering signals not accompanied by actual sparkover conditions in the load. Since termination of normal pulse cycles in such pulser systems are accomplished by a return to high forward voltage across the switching elements, false triggers generated closely prior to such termination and within the forward recovery time of a thyristor switching element present a danger that the termination of a normal cycle will result in a weak turn-on and consequent damage of the switching element. By insuring that all such potentially false triggers have a duration which extends past termination of the pulse cycle damage to the switching element resulting from such false triggers is inhibited.

Abstract: 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.