Optimised hybrid shielding and magnetic field control for emerging quantum technologies

作者：Peter J. Hobson, Michael Packer, Niall Holmes, Alister Davis, Prashant Patel, Darragh Holmes, Robert Harrison, James D. Chalmers, Ben Styles, David Woolger, Dom Sims, Matthew J. Brookes, Richard Bowtell, T. M. Fromhold · 年份：2021 · DOI：10.1117/12.2598780 · 被引用次数：5 · 研究领域：Atomic and Subatomic Physics Research、Quantum, superfluid, helium dynamics、Cold Atom Physics and Bose-Einstein Condensates

The accurate control of magnetic fields is a cornerstone of multiple emerging quantum technologies. These technologies often require passive high permeability magnetic shielding and internal active field-generating coils to create their own bespoke magnetic field landscape. However, magnetic fields generated by coils are distorted by high permeability shielding, preventing the accurate and efficient generation of the desired field environment. Here, we design a cylindrical four-layer magnetic shield with an interior hybrid active-passive coil system that is explicitly optimised to include the electromagnetic coupling between the active and passive components. We use a combination of analytical methods and numerical simulations to determine the shield parameters - geometry, thickness, and access hole positions - to maximise the passive shielding efficiency and minimise the shield-induced Johnson noise and weight. Then, we apply an analytical formulation of the magnetic field, which accounts for the interaction with the magnetic shield, to design nine orthogonal hybrid active-passive field-generating coils inside the shield. The coils will be manufactured on thin low-via flex-PCBs near the shield's interior surface and generate three uniform fields and six gradient fields that deviate by less than 0.4% and 2%, respectively, over an internal cylindrical region extending over half the diameter and length of the innermost shield layer. These hybrid active-passive coils can accurat...