Siemens Aktiengesellschaft

Gerd Seifert

Kurt Franke

Horst Aichinger

Hartmut Krause

In an exemplary embodiment, an anode assembly is magnetically mounted free of contact. In order to carry off the anode current, on a part rotating with the anode assembly, an auxiliary cathode is arranged opposite which a stationary auxiliary anode is disposed. The auxiliary cathode is an oxide cathode which is centrically arranged on the rotary anode assembly and opposite which a stationary heater is disposed.

Rotary anode x-ray tube

In an exemplary embodiment, a control loop for the x-ray tube current is present which adjusts the x-ray tube current to a value which is a function of the exposure time and the selected mAs-product. In order that deviations of the x-ray tube voltage from a desired value can be controlled via the x-ray tube current, but that the mean value of the x-ray tube current can nevertheless be kept constant, a phase angle control device, arranged in the primary circuit of the high voltage transformer, can be present as the regulating unit for the mean value of the x-ray tube current. As controller for the x-ray tube voltage, a circuit for the adjustment of the filament current of the x-ray tube can be provided.

X-Ray diagnostic system comprising means for the fixed specification of

In an exemplary embodiment a rotary anode motor is likewise supplied by the inverter circuit which is in the form of a full bridge with two pairs of alternately closable electronic switches. In one bridge diagonal the load (e.g. the x-ray tube) is disposed, while a d.c. voltage source is connected to the other bridge diagonal. The rotary anode motor is capable of connection, via a switch, to a connection point at one side of the load diagonal, and the bridge-half at the opposite side of the load diagonal is capable of being maintained in an open circuit condition during motor operation.

X-Ray diagnostic generator comprising an inverter circuit feeding the

In an exemplary embodiment, a housing of shielding material, surrounding the cathode coils, has an opening for the transmission of the stream of electrons to the anode. A device for effecting a relative movement between the housing and the cathode coils is present, by means of which one of the cathode coils is selectively capable of being covered. The cathode coils can be mounted on a holder which is pivotal about the x-ray tube longitudinal axis by means of electromagnets. The electromagnets can be connected to the output of the filament supply transformer, associated with the respective cathode coil, and a multiplex circuit can be provided for the transmission of the control signals.

X-Ray tube comprising two cathode coils

In the exemplary embodiment the temperature-dependent resistance of the cathode coil is taken as the measure of the instantaneous coil temperature and is employed for the purpose of dimensioning an increased filament power in the transition time between fluoroscopy and radiography, or for the purpose of dimensioning a heating pause in the transition time between radiography and fluoroscopy, respectively.

Installation for determining the temperature of the heater coil of an

The inverter utilizes an LC oscillatory circuit and a switching device for the alternate connection of this oscillating circuit to a d.c. voltage source. Adjustment circuitry is present for the adjustment of the capacitance and/or inductance of the LC oscillatory circuit. Through this circuitry, the inverter is adaptable to different load conditions.

X-ray diagnostic generator comprising an inverter supplying the high

The output voltage of the inverter is supplied to a high voltage transformer to which an X-ray tube with a rotating anode is connected. The rotating anode motor is likewise fed by the inverter. To this end, the inverter can be selectively operated with a high frequency for feeding the X-ray tube and a low frequency for feeding the rotating anode motor. But it is also possible to supply the inverter output voltage in parallel to the high voltage transformer and to a frequency divider at whose output the rotating anode motor lies.

X-ray diagnostic generator with an inverter feeding the high voltage

In an exemplary embodiment, an inverter manifests a load output which is capable of being alternately connected, via a switching apparatus with the poles of a d.c. voltage source. Changeover switches are present by means of which the load output can be selectively connected between a midpoint conductor of the d.c. voltage source and the midpoint of a half-bridge formed by the switching apparatus, or into the diagonal of a full-bridge formed by the switching apparatus. The changeover switches for the formation of the half-bridge, parallel-connect two branches of the full-bridge in each instance. By this means, the inverter is capable of being adapted selectively to a high voltage or a high current load.

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Spardorf, Germany

Gerd Seifert