Multipole Element Layout for Vacuum-Stable Particle Beam Correction
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Solution Overview
Problem
In particle beam systems, multipole elements with coils inside the vacuum region outgas, compromising the vacuum and requiring complex and expensive encapsulations, while placing coils outside the vacuum region necessitates vacuum seals for magnetic flux guidance, which is challenging, especially for converting to electric-magnetic multipole elements.
Innovation Solution
A multipole element design with coils in an external space assembly and magnetically conductive pole pieces and supports within a vacuum tube, allowing magnetic flux to form a multipole field without vacuum seals, and enabling easy electrical insulation of pole pieces for different potentials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If coils are arranged inside the vacuum region, then magnetic multipole field can be created, but outgassing from coil insulation impairs the vacuum
Solution Approach 1:
The multipole element is divided into two separate assemblies: an external space assembly containing the coils and a vacuum space assembly containing the pole pieces. This segmentation allows the coils to be positioned outside the vacuum region, eliminating outgassing issues while still enabling magnetic field creation through the magnetically conductive supports and pole pieces.
2Reliability
If coils are arranged outside the vacuum region, then outgassing does not influence vacuum, but vacuum seals are required to guide magnetic flux into vacuum region
Solution Approach 1:
The coils are extracted from the vacuum region and placed in the external space assembly. The magnetically conductive supports extend from the external space into the vacuum space, providing a path for magnetic flux without requiring vacuum seals. This extraction eliminates the need for complex vacuum seal arrangements while maintaining magnetic field functionality.
3Reliability
If pole pieces pass through separating wall with vacuum seals, then magnetic flux can be guided into vacuum region, but sealing becomes complicated
Solution Approach 1:
Magnetically conductive supports act as intermediaries, extending from the external space assembly through the tube wall into the vacuum space assembly. These supports provide a continuous magnetic flux path without requiring the pole pieces to pass through the vacuum seal, thereby simplifying the sealing arrangement while maintaining magnetic field creation capability.
4Adaptability or versatility
If magnetic multipole element is enhanced to electric-magnetic multipole element, then functionality is improved, but electrical insulation becomes necessary
Solution Approach 1:
The multipole element is segmented into external and vacuum spaces, with the tube providing electrical insulation between them. This segmentation allows pole pieces in the vacuum region to be electrically insulated from the external components, enabling the creation of electric-magnetic multipole elements without complex insulation arrangements.
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 configuration maintains a stable vacuum, reduces outgassing issues, and simplifies the sealing process, allowing for efficient creation of magnetic multipole fields and potential electric-magnetic multipole fields without the need for complex vacuum seals, enhancing the functionality of particle beam devices like electron beam microscopes and ion beam processing systems.
Implementation Method 1
The coils are assigned to the supports. The magnetic flux which flows through the tube and further through the pole pieces is excited in the circumferential pole piece and the supports by the coils
Implementation Method 2
Magnetic fluxes which flow through the tube and further through the pole pieces are excited in the circumferential pole piece and the supports by the coils. The magnetic flux emerges from the pole pieces at gaps between the pole pieces and forms a magnetic multipole field in the process
Data Source
AI summary
A multipole element for creating a magnetic multipole field or for creating an electric-magnetic multipole field for a particle beam system such as a scanning electron microscope, for example, comprises: a tube surrounding a central axis of the multipole element; an external space assembly arranged outside of the tube and a vacuum space assembly arranged within the tube. The external space assembly comprises: a magnetically conductive circumferential pole piece surrounding the tube; a plurality of magnetically conductive supports arranged so as to be distributed around the central axis and extending from the circumferential pole piece up to an outer wall surface of the tube; and a plurality of coils. The vacuum space assembly comprises a plurality of magnetically conductive pole pieces arranged so as to be distributed around the central axis and extending from the tube in the direction of the central axis.