Rotatable CT X-Ray Target Support for Focal Spot Accuracy
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Solution Overview
Problem
Existing computed tomography (CT) systems face challenges in maintaining accurate measurements due to target wear in X-ray tubes, particularly in transmission targets, which require manual intervention and complex corrections, and lack automated solutions for rotating targets to manage focal spot shifts.
Innovation Solution
The target carrier in X-ray tubes is designed to be rotatable outside or within the vacuum tube using external or internal rotating means, coupled with a drive system for automated control, allowing incremental or wear-dependent rotation to maintain focal spot accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the target is rotated continuously during measurement, then higher X-ray powers can be used with the same focal spot size, but the target may melt due to excessive heat input
Solution Approach 1:
The target is rotated in discrete angular increments between measurements rather than continuously, allowing periodic heat dissipation while maintaining operational power levels. This periodic rotation enables the focal spot to move to fresh areas of the target coating, distributing thermal load and preventing melting.
2Ease of operation
If the target carrier is loosened and manually turned to rotate the target, then the target can be repositioned, but the process is time-consuming and cannot be automated
Solution Approach 1:
The manual mechanical rotation system is replaced with an automated drive mechanism that can rotate the target carrier programmatically. This substitution eliminates the need for manual intervention while maintaining the ability to reposition the target, significantly reducing the time required for target rotation and enabling automation of the measurement process.
3Adaptability or versatility
If the electron beam is deflected to a different area of the target coating, then the focal spot can be shifted, but complex correction is required to ensure accurate measurements
Solution Approach 1:
The complexity of beam deflection and correction systems is extracted by instead rotating the entire target carrier mechanically. This approach achieves focal spot repositioning through a simpler, more direct method that eliminates the need for complex electronic beam deflection and associated correction algorithms, reducing overall system complexity while maintaining positioning flexibility.
4Reliability
If the target and target carrier are completely enclosed within the vacuum tube, then the vacuum seal is maintained, but the rotating bearing cannot be integrated with the vacuum tube's sealing system
Solution Approach 1:
A magnetic coupling mechanism serves as an intermediary between the external drive system and the internal target carrier. This intermediary allows rotational force to be transmitted through the vacuum wall without compromising the vacuum seal, enabling automated target rotation while maintaining vacuum integrity and avoiding complex integrated sealing solutions.
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 enables high-precision CT measurements by automatically adjusting the focal spot on the target, reducing the need for manual intervention and maintaining measurement accuracy despite target wear, applicable to both transmission and reflection targets.
Implementation Method 1
the target has an area that generates X-rays when irradiated with electrons, which is formed by a coating of a substrate
Implementation Method 2
the target has an area that generates X-rays when irradiated with electrons, which is formed by a coating of a substrate
Implementation Method 3
the target carrier is rotatable about an axis that penetrates the target offset from the point of impact (focal spot) of the electron beam on the target
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a device for examining workpieces by way of computer tomography, the device comprising a radiation source (20) for a computer tomograph, the source (20) comprising at least a main body (21), from which a vacuum pipe (22) containing a unit (23) for focusing an electron beam (24) on a target (25) starts, and a target support (26) closing the vacuum pipe (22), with the target (25) starting from the target support, and the target (25) having a region (28) generating X-ray radiation (27) when irradiated with electrons, said region being formed by a coating (28) of a substrate (26). The target support (26) is designed so as to be rotatable about an axis (30) which is penetrated by the target (25) in a manner offset in relation to the point of incidence (31) of the electron beam (32a, 32b) on the target (25). The device has means (33, 34, 35) arranged outside the vacuum pipe (22) for rotating (rotary means) the target support (26), said means (33, 34, 35) starting from the main body (21) itself and/or from a radiation-guiding body (36) starting from the main body (21) and arranged in the X-ray radiation (27).