Toroidal Degaussing Coil for Magnetic Shield Uniformity
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Solution Overview
Problem
Existing magnetic shielding systems face challenges in achieving uniform low magnetic fields and gradients over an area, with conventional degaussing coils providing non-uniform field distribution and passive shielding materials having limitations in reducing magnetic field gradients.
Innovation Solution
The implementation of a toroidal degaussing coil configuration around a cylindrical magnetic shield made of high permeability materials like Mumetal or Cryoperm, combined with active compensation coils and a superconducting plane for fluxon removal, enhances magnetic field uniformity and gradient control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional degaussing coils are used, then magnetic field reduction is achieved, but field uniformity deteriorates
Solution Approach 1:
The patent applies a toroidal (doughnut-shaped) geometry to the degaussing coil instead of conventional straight or solenoidal configurations. This curved, symmetric geometry distributes the magnetic field more uniformly around the shield structure, eliminating the non-uniform field distribution caused by conventional coil arrangements while maintaining effective magnetic field reduction.
Solution Approach 2:
The patent transitions from one-dimensional linear coil arrangements to a two-dimensional toroidal configuration that wraps around the shield in a closed loop. This dimensional change allows the magnetic field to be applied uniformly from all directions simultaneously, achieving both field reduction and uniformity that cannot be obtained with conventional linear coil geometries.
2Object-affected harmful factors
If passive shielding materials are used, then magnetic field reduction is achieved, but gradient control deteriorates
Solution Approach 1:
The patent employs active compensation coils that can dynamically adjust their current and magnetic field output in response to measured field gradients. Unlike static passive shielding materials, these active components can adapt to changing conditions and provide real-time gradient control, making the system versatile and controllable.
Solution Approach 2:
The patent implements a feedback control system where magnetic field sensors measure the actual field conditions and feed this information to control circuits that adjust the compensation coils accordingly. This closed-loop feedback mechanism enables precise gradient control and maintains optimal shielding performance under varying conditions.
3Manufacturing precision
If toroidal degaussing coil configuration is implemented, then field uniformity is improved, but device complexity increases
Solution Approach 1:
The patent combines the degaussing function with the shielding structure by integrating the toroidal coil directly around the cylindrical shield. This merging of functions eliminates the need for separate complex coil assemblies and simplifies the overall device architecture while maintaining the uniform field distribution benefits of the toroidal geometry.
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 toroidal degaussing coil design improves field uniformity within the shield volume, while active compensation coils and superconducting planes effectively reduce magnetic field gradients and trapped fluxons, creating a stable low-magnetic field environment suitable for superconducting devices.
Implementation Method 1
a degaussing coil, wherein the degaussing coil is wrapped around at least a portion of the shield structure in a toroidal configuration
Implementation Method 2
The shield structure may be formed of a material having high magnetic permeability selected from the group consisting of Finemet®, mu-metal, and cryoperm
Implementation Method 3
a fluxon barrier carried on the superconducting plane, wherein the fluxon barrier is positioned adjacent to an edge of the superconducting plane
Implementation Method 4
a superconducting chip may be summarized as including a plurality of superconducting devices; a superconducting plane positioned beneath the plurality of superconducting devices
Data Source
AI summary
Systems and methods for magnetic shielding are described. A magnetic shield formed of a material having a high magnetic permeability may be degaussed using a toroidal degaussing coil. The toroidal degaussing coil may enclose at least a portion of the shield. Magnetic field gradients may be actively compensated using multiple magnetic field sensors and local compensation coils. Trapped fluxons may be removed by an application of Lorentz force wherein an electrical current is passed through a superconducting plane.