# US 2014/0192961 A1 · Method and Apparatus for Heating Current Control of a Pulsed X-Ray Tube > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0192961 A1 - Document ID: US20140192961A1 - Status: Published application - Kind: A1 - Application number: 14/151,591 - Filed: 2014-01-09 - Published: 2014-07-10 - Earliest claimed: 2013-01-09 - Assignees: Siemens Aktiengesellschaft - Inventors: Rudolf Auernhammer; Andreas Böhme; Johannes Walk - Web page: https://patentgrep.com/patent/US20140192961A1 ## CPC - H05G 1/34: Anode current, heater current or heater voltage of X-ray tube - H05G: X-RAY TECHNIQUE (investigating or analysing materials by the use of X-rays G01N23/00; apparatus for X-ray photography G03B42/02; X-ray tubes H01J35/00; TV systems having X-ray input H04N5/321) ## Abstract A method and an associated apparatus for controlling a heating current flowing through an emitter of a pulsed X-ray tube during pulse pauses are provided. The heating current is controlled by comparing a measured actual value of the heating current with a predefinable desired value of the heating current. A low-pass filtering of the actual value of the heating current is effected before the comparison. A time constant of the low-pass filtering is equal to a thermal time constant of the emitter. A correction of the actual value of the heating current is provided before the low-pass filtering by a first correction value. The first correction value is determined such that a tube current control during the pulses is not compensated for by the heating current control in the pulse pauses. ## Claims ### Claim 1 A method for controlling a heating current flowing through an emitter of a pulsed X-ray tube during pulse pauses, the method comprising: comparing a measured actual value of the heating current with a predefinable desired value of the heating current; low-pass filtering the measured actual value of the heating current before the comparison, wherein a time constant of the low-pass filtering is equal to a thermal time constant of the emitter; and correcting the measured actual value of the heating current before the low-pass filtering by a first correction value, wherein the first correction value is determined such that a tube current control during the pulses is not compensated for by the heating current control in the pulse pauses. ### Claim 2 (depends on 1) The method of claim 1, wherein the first correction value is determined from a difference between the measured actual value of the heating current and an actual value of the heating current at the beginning of a present pulse. ### Claim 3 (depends on 1) The method of claim 1, further comprising subtracting the first correction value from the measured actual value of the heating current. ### Claim 4 (depends on 1) The method of claim 1, further comprising correcting the measured actual value of the heating current before the low-pass filtering by a second correction value, the second correction value being determined from a model of electron cooling during the pulses. ### Claim 5 (depends on 4) The method of claim 4, wherein the second correction value is determined such that thermal cooling caused by the electron cooling during the pulses is not registered. ### Claim 6 (depends on 4) The method of claim 4, further comprising subtracting the second correction value from the measured actual value of the heating current. ### Claim 7 (depends on 4) The method of claim 4, further comprising correcting the measured actual value of the heating current before the low-pass filtering by a third correction value, the third correction value being determined from a model of anode back heating. ### Claim 8 (depends on 7) The method of claim 7, further comprising adding the third correction value to the measured actual value of the heating current. ### Claim 9 An apparatus for controlling a heating current flowing through an emitter of a pulsed X-ray tube during pulse pauses, the apparatus comprising: a heating current control unit configured to control the heating current by comparing a measured actual value of the heating current with a predefinable desired value; a first low-pass filter unit that is connected upstream of the heating current control unit and comprises a time constant equal to a thermal time constant of the emitter, wherein the first low-pass filter is configured to filter the measured actual value of the heating current before the comparison; and a first correction unit configured to: alter the measured actual value of the heating current before the low-pass filtering by a first correction value K1; and determine the first correction value such that a tube current control during the pulses is not compensated for by the heating current control unit in the pulse pauses. ### Claim 10 (depends on 9) The apparatus of claim 9, wherein the first correction unit is further configured to determine the first correction value from a difference between the measured actual value of the heating current and an actual value of the heating current at the beginning of a present pulse. ### Claim 11 (depends on 9) The apparatus of claim 9, further comprising a summing unit that is connected upstream of the first low-pass filter unit and is configured to subtract the first correction value from the measured actual value of the heating current. ### Claim 12 (depends on 9) The apparatus of claim 9, further comprising a second correction unit configured to: alter the measured actual value of the heating current before the low-pass filtering by a second correction value; and determine the second correction value from a model of electron cooling during the pulses. ### Claim 13 (depends on 12) The apparatus of claim 12, wherein the second correction unit comprises a second low-pass filter unit, a time constant of the second low-pass filter unit being equal to a time constant of the electron cooling. ### Claim 14 (depends on 11) The apparatus of claim 11, wherein the summing unit is configured to add the second correction value to the measured actual value of the heating current. ### Claim 15 (depends on 12) The apparatus of claim 12, further comprising a third correction unit configured to: alter the measured actual value of the heating current before the low-pass filtering by a third correction value; and determine the third correction value from a model of anode back heating. ### Claim 16 (depends on 15) The apparatus of claim 15, wherein the summing unit is configured to subtract the third correction value from the measured actual value of the heating current. ### Claim 17 An X-ray generator comprising: an apparatus for controlling a heating current flowing through an emitter of a pulsed X-ray tube during pulse pauses, the apparatus comprising: a heating current control unit configured to control the heating current by comparing a measured actual value of the heating current with a predefinable desired value; a first low-pass filter unit that is connected upstream of the heating current control unit and comprises a time constant equal to a thermal time constant of the emitter, wherein the first low-pass filter is configured to filter the measured actual value of the heating current before the comparison; and a first correction unit configured to: alter the measured actual value of the heating current before the low-pass filtering by a first correction value K1; and determine the first correction value such that a tube current control during the pulses is not compensated for by the heating current control unit in the pulse pauses. ### Claim 18 (depends on 17) The X-ray generator of claim 17, wherein the first correction unit is further configured to determine the first correction value from a difference between the measured actual value of the heating current and an actual value of the heating current at the beginning of a present pulse. ### Claim 19 (depends on 17) The X-ray generator of claim 17, wherein the apparatus further comprises a summing unit that is connected upstream of the first low-pass filter unit and is configured to subtract the first correction value from the measured actual value of the heating current. ### Claim 20 (depends on 17) The X-ray generator of claim 17, wherein the apparatus further comprises a second correction unit configured to: alter the measured actual value of the heating current before the low-pass filtering by a second correction value; and determine the second correction value from a model of electron cooling during the pulses.