Variable-Focus Magnetostatic Lens for Charged Particle Beams
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Solution Overview
Problem
Conventional lenses for charged particle beams, particularly those based on electromagnets, face challenges with power consumption, heat generation, and mechanical complexity, making them unsuitable for applications with limited power, size, and weight constraints, such as satellites and portable systems.
Innovation Solution
The development of variable-focus solenoidal lenses using permanent magnets with integrated emittance filtering, which includes collimator plates and magnetically permeable yokes, allowing for adjustable focus and magnetic field strength without the need for power, reducing size and cost, and minimizing heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If electromagnets are used for focusing charged particle beams, then magnetic field strength can be adjusted, but power consumption and heat generation increase significantly
Solution Approach 1:
The lens is divided into multiple permanent magnet segments (e.g., six segments) that can be independently positioned. By adjusting the spacing between segments, the effective magnetic field strength is varied without requiring power input, thus resolving the contradiction between energy efficiency and field adjustability.
Solution Approach 2:
The permanent magnet lens system incorporates movable components that allow dynamic adjustment of the magnetic field configuration. The segments can be repositioned along the beam axis to change focal length and field strength, providing adaptability without consuming electrical power.
2Use of energy by stationary object
If permanent magnets are used for focusing, then power consumption is reduced, but mechanical complexity and fabrication cost increase
Solution Approach 1:
Each permanent magnet segment serves multiple functions: it provides the magnetic field for focusing, acts as a mechanical spacer when positioned, and can be individually adjusted for alignment. This multi-functionality reduces the need for separate adjustment mechanisms, thereby reducing overall mechanical complexity despite using permanent magnets.
3Volume of moving object
If electromagnets are used, then magnetic field can be generated, but physical size and weight increase
Solution Approach 1:
The patent utilizes permanent magnets with specific remanence values (e.g., NdFeB magnets with Br ≥ 1.2 Tesla) to achieve high magnetic field strength in a compact volume. By changing the material parameters of the magnets, the system achieves strong focusing capability without increasing physical size, resolving the contradiction between compactness and field generation capability.
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 solution provides a compact, cost-effective, and efficient focusing system for charged particle beams with adjustable focus, capable of achieving high beam quality and reduced spherical aberration, suitable for various applications including space missions and dielectric laser accelerators, while minimizing power consumption and heat generation.
Implementation Method 1
a first permanent ring magnet having a field oriented in a first direction and a second permanent ring magnet having a field oriented in a second direction that is opposite to the first direction
Data Source
AI summary
Variable-focus solenoidal lenses for charged particle beams with integrated emittance filtering are disclosed. The emittance may be controlled via selection of collimating irises. The focal length may be changed by altering the spacing between two permanent ring magnets.