QT-Shield: Compact lightweight high performance magnetic shielding enabling portable & miniaturised quantum technology systems

Magnetic shielding is an essential component of all second generation quantum technology (QT) systems necessary to eliminate magnetic interference and enable quantum behaviour to be observed. For accurate operation magnetic fields must be reduced to <150 microGuass with <0.1% variation. A particular challenge for quantum systems is shielding of low frequency (<40Hz) and DC magnetic fields. Best available materials are soft magnetic alloys, such as MuMetal. Due to limited shielding design knowhow, manufacturers currently adopt a costly trial and error design approach. Shield geometries are kept simple (spherical / cylinders) as these are known to provide reliable conduction surfaces; whilst material thickness is kept high to ensure reliable shielding. Existing shielding is thus heavy and bulky, limiting the advancement of QT towards portable and miniaturised systems. Shielding is uniquely designed for each application, often with low production volume. Production is currently through hand machining in workshops; thereby limiting production sale-up and creating a vulnerability to low wage economies abroad.

The QT-Shield solution will apply advanced shielding design principles for the realisation of high performance compact-lightweight magnetic shielding delivering a >50% reduction in weight and >40% reduction in area compared to conventional approaches. Such shield designs will be achieved by:
- making the shields more compact so that less shield area (and thus material) is required; and
- minimising layer thickness to only that which is required (at that point) to achieve the target magnetic field environment at the site of interest.

High performance shielding will be maintained, despite deviations from near spherical / cylindrical geometries through advanced 'idealised' shielding geometries and clever use of multi-layer systems.

The compact shielding designs will be made through the integration of advanced manufacturing techniques:
- 3D Printing - enabling accurate direct printing of fully (individually) customisable complex shielding shapes
- 5-Axis milling - enabling tailored reduction of material thickness across the entire shielding area

3D printing and 5-Axis machining are fully automated manufacturing processes enabling shielding production to transition towards mass customisation (high volume production of unique shield shapes).

The purpose of the QT-Shield project is to demonstrate feasibility for: i) use of advanced design principles for the realization of lightweight, compact and high performance magnetic shielding suitable for QT applications; ii) manufacture of advanced designs using 3D printing and 5-axis machining; and iii) use of the advanced shielding designs for protection of a quantum gravity sensor demonstrator system.

Project outputs will include:
- Market study identifying the most important opportunities & requirements for compact magnetic shielding
- Demonstration of feasibility for achieving >50% weight and >40% volume reduction whilst maintaining reliable shielding performance
- Demonstration of feasibility for the manufacture of complex shielding designs using 3D printing and 5-axis milling techniques
- Prototype compact lighting shielding system demonstrating feasibility for protection of an existing quantum gravity sensor system

High performance, lightweight, fully customisable magnetic shielding not only addresses the emerging market needs of quantum devices (enabling the realisation of compact portable and miniaturised devices); but also important needs across a broad range of existing market sectors (opening new market applications within aerospace, defence, space, automotive, electronics etc...). Furthermore, knowledge based advanced shielding designs also provide clear differentiation within the market and, when combined with highly automated manufacturing process enabling mass customisation at low cost, support the long term competitiveness of UK industry.

Scientific Impact: our group will create scientific impact in three areas:
1) we will support investigation of magnetic shielding design principles enabling holistic design of advanced shielding structures that optimise shielding performance whilst minimizing weight and volume. More specifically new knowledge will be acquired concerning the relationships between shielding attenuation and: i) shield diameter & layer thickness; iii) shielding shape; & iii) multi-layer shielding design (shape, distance of air-gap). The results will form a foundational knowledge base that may be further developed for the realization of design tools and best practice. Research in this field has been restricted to date due to the limited market size and lack of investment. With growth of QT providing high volume markets; it is anticipated that investment and research in this field will grow substantially.
2) to date little research has been undertaken exploring 3D printing of MuMetals for magnetic shielding applications. We will expand scientific knowledge through an understanding of the relationships between the laser sintering parameters and the resulting material properties; and more specifically how laser sintering effects: i) material grain size and subsequent grain growth and alignment during annealing; ii) printing resolution and the limits of shielding layer thickness via the 3D printing techniques; & iii) the resulting material mechanical properties and surface finish. This knowledge will not only support research into the manufacture of shielding materials, but also other fields where magnetic materials are used, such as electronics, imaging, superconducting systems and sensors.
3) conventional magnetic shielding is bulky and sits around the quantum experiment. The ability to manufacture advanced shielding structures enables the design of more compact quantum systems. The performance of such systems have not previously been explore and in particular: i) robustness and strength in use; ii) impact of joining and shield opening with decreasing shield size; & iii) reliability of shielding in different environments and with compaction of the quantum experiment. Feasibility testing within our demonstrator system will provide foundational knowledge to support further research in this field.

Technology Impact: QT-Shield will deliver to a number of technology advancements, including:
1) Shielding Design Principles: feasibility of advanced shielding design principles for achieving >50% weight reduction and >40% volume reduction
2) Advanced Manufacturing Processes: feasibility for the manufacture of advanced shielding designs using 3D printing and 5-axis machining
3) Packaging for Compact Shielding: packaging solutions for lightweight compact shields that enable mechanical strength and robustness
4) Prototype shielding system for QT demonstrator: feasibility of an advanced shielding design within a QT gravity sensor demonstrator

The project outputs form a platform from which commercial technologies may be developed; not only in terms of QT magnetic shielding, but also other markets for magnetic shielding or use of 3D printed magnetic materials.

Market Impact: High performance, lightweight, fully customisable low frequency (and DC) magnetic shielding not only addresses the emerging market needs of quantum devices (enabling the realisation of compact portable and miniaturised devices); but also important needs across a broad range of existing market sectors (opening new market applications within aerospace, defence, space, automotive, electronics etc...). Knowledge based 'idealised' shielding designs will provide clear differentiation within the market place; and through patent protection, sustainable globally competitive advantage will be achieved. Automated 3D printing and 5-Axis machining processes will enable customisation at low cost, thereby ensuring long term competitiveness against low cost economies such as China.