X-ray Tube Grid Control via Integrated Rectifier
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Solution Overview
Problem
Traditional X-ray tube grid control systems are limited by capacitance between the grid conductor and filament conductor, which restricts the speed at which the tube current can be cycled on and off due to the use of DC current in high voltage cables.
Innovation Solution
The system employs an AC current generated by a power source separate from the X-ray tube, which is converted to DC current by a rectifier integrated within the tube, reducing capacitance and enabling faster cycling of the tube current through the use of a grid conductor within a high voltage cable.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If DC current is used in the high voltage cable to power the grid electrode, then the grid electrode can effectively control the tube current, but the capacitance between the grid conductor and filament conductor limits the speed at which tube current can be cycled on and off
Solution Approach 1:
The patent changes the electrical parameter of the power supply from DC to AC, specifically using high-frequency AC current. This parameter change eliminates the capacitance limitation because AC current does not charge the capacitance between conductors in the same way DC does, thereby enabling faster tube current cycling while maintaining effective grid electrode control
Solution Approach 2:
The patent employs periodic AC current at high frequency to power the grid electrode. This periodic action allows the grid conductor to rapidly switch the tube current on and off by cycling the power supply frequency, achieving fast transition times required for modern imaging applications
2Device complexity
If the power source is disposed apart from the X-ray tube, then the high voltage cable can be used to transmit power, but the capacitance in the cable limits the switching speed
Solution Approach 1:
The patent changes the power transmission parameter from DC to high-frequency AC, which allows the power source to be disposed apart from the X-ray tube while connected via high voltage cable. The AC parameter change eliminates capacitance limitations, enabling fast grid voltage transitions despite the physical separation and cable connection
3Speed
If a rectifier is integrated into the X-ray tube, then AC current can be converted to DC current for the grid electrode, but the rectifier adds device complexity
Solution Approach 1:
The patent merges the rectifier function with the existing power supply system by integrating it into the X-ray tube assembly. This consolidation allows AC-to-DC conversion to occur at the tube level, enabling fast grid voltage transitions while consolidating components rather than adding separate external equipment
Solution Approach 2:
The rectifier serves as an intermediary component that converts AC current from the power source to DC current suitable for the grid electrode. By placing this intermediary function within the tube assembly, the system achieves fast transitions while managing the complexity through functional integration
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 allows for faster transition times of the grid voltage, improving image quality and operational safety by enabling sharper transitions, particularly beneficial for vascular applications requiring rapid switching.
Implementation Method 1
The rectifier is operative to convert the AC current to a DC current that powers the grid electrode
Implementation Method 2
grid voltages are typically negative, e.g., negative five kilovolts (-5 kV) with respect to a cathode voltage of about negative one-hundred-and-twenty kilo volts (-120 kV). Thus, removing a grid voltage, e.g., making the grid electrode neutral, allows the tube current to flow from the cathode to the anode
Implementation Method 3
As electrons within the electron beam impact the anode, their kinetic energy is converted to high-energy electromagnetic radiation, e.g., X-rays
Data Source
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AI summary
A system 10 for grid control of an electromagnetic ray tube 14 is provided. The system 10 includes a power source 50, a rectifier 124, and a grid conductor 125. The power 50 source is disposed apart from the electromagnetic ray tube 14 and operative to generate an AC current. The rectifier 124 is integrated into the electromagnetic ray tube 14 and electrically coupled to a grid electrode 122 of the electromagnetic ray tube 14. The grid conductor 125 electrically couples the power source 50 to the rectifier 124. The rectifier 124 is operative to convert the AC current to a DC current that powers the grid electrode 122.