X-Ray Source Filament Current Control for Pulse Temperature Drift
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Solution Overview
Problem
Existing X-ray sources, particularly in pulsed operation, face filament wear-out due to temperature drift during repeated X-ray pulses, leading to potential errors and reduced lifetime.
Innovation Solution
A controller for a high voltage generator adjusts filament current during emission pauses to maintain optimal temperature by alternating between blanking and boosting currents, using adaptive models to correct deviations in emission current and temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the filament temperature is maintained at operational level continuously, then the X-ray emission current is stable, but the filament wears out faster and lifetime is reduced
Solution Approach 1:
The patent applies periodic action by implementing alternating blanking and boosting current phases during emission pauses. The filament current is periodically reduced to blanking level and then increased to boosting level, creating a cyclic temperature profile that reduces cumulative thermal stress while maintaining operational stability through controlled temperature fluctuations.
Solution Approach 2:
The patent changes the filament current parameter dynamically by switching between operational, blanking, and boosting current levels. This parameter modification allows the filament temperature to vary in a controlled manner, reducing wear during blanking phases while ensuring adequate temperature for X-ray emission during operational phases.
2Duration of action of stationary object
If the filament current is reduced during emission pauses to decrease temperature, then filament wear is reduced, but temperature drift occurs over multiple pulses
Solution Approach 1:
The patent implements feedback by measuring the actual emission current and comparing it with expected values. Based on this comparison, the controller adjusts the boosting current magnitude and duration to correct temperature deviations, ensuring the filament returns to the desired operational temperature while maintaining reduced wear from blanking phases.
Solution Approach 2:
The system performs self-correction by using the emission current measurement as an indicator of filament temperature state. The controller automatically adjusts subsequent blanking and boosting currents to maintain optimal temperature, allowing the system to self-regulate without external intervention.
3Duration of action of stationary object
If repeated boosting and blanking of filament temperature is applied, then filament lifetime is extended, but deviations in temperature levels occur over multiple pulses
Solution Approach 1:
The patent uses feedback control by continuously monitoring emission current as a proxy for filament temperature. The measured emission current is compared with expected values, and the controller adjusts the boosting current parameters (magnitude and duration) to correct any temperature drift accumulated over multiple pulse cycles, maintaining precise temperature control.
Solution Approach 2:
The patent applies dynamics by making the boosting current parameters adaptive rather than fixed. The boosting current magnitude and duration are dynamically adjusted based on measured emission current deviations, allowing the system to respond to changing thermal conditions and maintain temperature accuracy over extended operation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach stabilizes filament temperature, reducing wear and enhancing the lifetime of X-ray sources by minimizing temperature drift and errors in X-ray emission.
Implementation Method 1
provide an operational filament current to heat a filament of a cathode of the X-ray source to an operational filament temperature during the plurality of X-ray pulses to generate a desired X-ray imaging emission current
Implementation Method 2
When a filament current is applied to the filament, the filament current heats the filament, causing the filament to expel electrons (thermionic emission), creating a space charge
Implementation Method 3
A peak X-ray tube voltage is applied across the cathode and the anode, and causes a beam of the electrons to accelerate from the cathode and impinge the anode
Implementation Method 4
An interaction of the electrons with the material of the anode produces heat and radiation, including X-rays
Data Source
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AI summary
Controlling a high voltage generator for an X-ray source includes: providing (410) power to the X-ray source to generate a plurality of X-ray pulses during a pulsed X-ray imaging run, wherein subsequent X-ray pulses of the plurality of X-ray pulses are temporally separated by an emission pause comprising a first part and a second part; providing (420) an operational filament current to heat a filament of a cathode of the X-ray source to an operational filament temperature during the plurality of X-ray pulses to generate a desired X-ray imaging emission current during the X-ray pulses; providing (430) a blanking filament current during the first part of the emission pauses, wherein the blanking filament current is lower than the operational filament current, to allow the filament temperature to decrease to an intercooler filament temperature; providing (440) a boosting filament current during the second part of the emission pauses, wherein the boosting filament current is higher than the blanking filament current, to increase the filament temperature from the intercooler filament temperature to the operational filament temperature; receiving (450) a measured emission current, the operational filament current, and an operational source voltage of an X-ray pulse, wherein the measured emission current is measured during the X-ray pulse at the operational filament current and the operational X-ray source voltage; determining (460) an expected emission current of the X-ray pulse, in dependence on the operational filament current and the operational X-ray source voltage; and adapting (470) the duration of providing the blanking current during the first part of a subsequent emission pause, and/or adapting the duration of providing the boosting current during the second part of the subsequent emission pause, to correct the operational filament temperature of a subsequent X-ray pulse for a difference between the measured emission current and the expected emission current.