Cathode Adjustment Window Tuning for X-Ray Tube Focal Point Control
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Solution Overview
Problem
Current X-ray tube technologies face limitations in achieving rapid switching of tube current and suppressing ineffective dose, leading to increased emittance of electron beams and restricted spatial resolution due to the size of the beam spot, which hinders the improvement of spatial resolution in energy-spectrum Computed Tomography (CT) applications.
Innovation Solution
The X-ray tube design includes a cathode structure with a cathode adjustment window and a controller that adjusts the potential difference between the cathode and the adjustment window to control the emittance of electron beams, allowing for precise adjustment of the electron beam spot size to match target focal point sizes, enabling flexible adjustment of focal points from ultra-large to ultra-small ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If rapid switching of tube current is achieved, then temporal resolution is improved, but emittance of electron beam increases dramatically
Solution Approach 1:
The patent implements dynamic control of the cathode adjustment window potential relative to the cathode potential, allowing the system to adaptively modulate electron beam emittance in real-time during rapid tube current switching. This dynamic potential adjustment enables the system to maintain low emittance even during microsecond-scale current transitions, resolving the contradiction between switching speed and beam quality.
2Manufacturing precision
If focusing quadrupole magnet current is increased to reduce beam spot size, then spatial resolution is improved, but device complexity and power consumption increase significantly
Solution Approach 1:
The patent applies preliminary action by adjusting the cathode adjustment window potential before electron emission occurs, pre-conditioning the electron beam to have lower emittance. This preliminary potential adjustment reduces the subsequent focusing requirement, allowing smaller beam spot sizes to be achieved with reduced quadrupole magnet current, thereby decreasing device complexity and power consumption.
3Productivity
If cathode temperature is increased to increase tube current, then productivity is improved, but focal point size control becomes limited
Solution Approach 1:
The patent changes the control parameter from cathode temperature to cathode adjustment window potential. By adjusting the potential difference between the cathode adjustment window and the cathode, the system can independently control both tube current magnitude and focal point size without being constrained by thermal limitations. This parameter change enables simultaneous optimization of productivity and adaptability across ultra-large to ultra-small focal point ranges.
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 solution allows for real-time adjustment of tube current and focal point size, significantly expanding the adjustment range of CT spatial resolution, enabling high temporal and spatial resolution in X-ray imaging applications.
Implementation Method 1
a cathode configured to emit an electron beam
Implementation Method 2
adjusting a potential difference between the cathode adjustment window and the cathode, so that a size of an electron beam spot formed by the electron beam matches a target focal point size
Data Source
AI summary
Embodiments of the present disclosure provide an X-ray tube. The X-ray tube may include a cathode assembly. The cathode assembly may include: a cathode configured to emit an electron beam; a cathode adjustment window disposed at a periphery of the cathode; and a controller configured to adjust emittance of the electron beams emitted from the cathode at different tube voltages by adjusting a potential difference between the cathode adjustment window and the cathode, so that a size of an electron beam spot formed by the electron beam matches a target focal point size.