Alignment Assembly for X-ray Microscopy Centering
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Solution Overview
Problem
Current x-ray microscopy applications face challenges in achieving precise sample rotation and alignment, particularly in maintaining the region of interest within the field of view during tomographic reconstruction, due to limitations in translation and angular motion precision, which can result in translational errors and resolution loss.
Innovation Solution
A sample rotation system with precise actuators and sensors for 3D motion control, combined with a compact alignment assembly using linear slides and actuators, ensures accurate centering and minimizes translational errors by using magnetic preloading and materials with low thermal expansion coefficients, maintaining stability and precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If traditional alignment assemblies with large and heavy bearing stages are used, then the structure provides stability, but the device complexity and mass increase, reducing dynamic stability and resonant frequency
Solution Approach 1:
The alignment assembly is divided into separate functional components: a rotation stage for angular positioning, linear slides for translational adjustment, and actuators for precise positioning. This segmentation allows each component to be optimized independently, reducing overall complexity while maintaining stability
Solution Approach 2:
Traditional heavy mechanical bearing stages are replaced with a combination of linear slides and actuators. The actuators use magnetic or friction forces for positioning, substituting complex mechanical support structures with simpler, more controllable actuation mechanisms, thereby reducing mass and complexity while improving dynamic stability
2Ease of operation
If complex cable arrangements are used in traditional alignment assemblies, then power and signals can be transmitted, but the device complexity and parasitic motion increase
Solution Approach 1:
The actuator is physically separated from the slides and mounted on a stationary support structure. This extraction eliminates the need for complex cable arrangements that would otherwise be required to power and control actuators mounted on rotating or moving stages, reducing parasitic motion and simplifying the overall system
Solution Approach 2:
A stationary support structure serves as an intermediary, mounting the actuator outside the rotating assembly. This allows power and control signals to be transmitted to the actuator without requiring cables to pass through or along the rotation stage, eliminating a major source of complexity and parasitic motion
3Measurement precision
If initial alignment is performed with high precision, then the region of interest can be centered on the rotation axis, but additional alignment procedures are still required during rotation due to translational errors
Solution Approach 1:
Sensors continuously monitor the position of the rotation stage and provide feedback to actuators, which make real-time adjustments to maintain precise alignment. This closed-loop feedback system compensates for translational errors during rotation, eliminating the need for additional alignment procedures and maintaining high precision throughout the rotation range
Solution Approach 2:
The rotation stage is pre-aligned to the center of the field of view before operation. This preliminary alignment, combined with continuous feedback control during rotation, ensures that the region of interest remains centered without requiring additional alignment procedures, saving time while maintaining precision
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
The system achieves high-precision sample rotation and alignment, reducing translational errors and maintaining stability, enabling accurate 3D reconstruction without additional alignment procedures and minimizing artifacts in x-ray microscopy applications.
Implementation Method 1
The slides are magnetically preloaded, in one example, to maintain their position after the adjustment
Implementation Method 2
the stage structures are made of a material with low thermal expansion coefficient materials, such as Invar (FeNi)
Data Source
AI summary
Alignment assembly is used to center a sample on a moving stage system. The alignment assembly includes a pair of slides stacked on a stage with linear perpendicular movement relative to each other, and at least one actuator that is preferably physically separate from the linear slides and stage. The actuator(s) repeatedly extend an actuator arm to move the linear slides, and retract the arm for subsequent movement of the stage during and after the process of centering the sample in two dimensions on the stage. Either the stage system rotates, or multiple actuators are placed to move the alignment system in perpendicular directions relative to the stage, by repeatedly contacting only the top linear slide.