WP7 – Permanent Magnets
Raffaella Geometrante
“The objective of this work package is not only to develop and assess permanent magnet technologies for future accelerator applications, but also to introduce a stronger industrial approach to innovation in this field.
Permanent magnets represent a strategic technology, both for research infrastructures and for Europe more broadly, as they can contribute to reducing energy consumption while strengthening technological and industrial competitiveness and long-term sustainability.
In this work package, the ambition is therefore not limited to laboratory-scale prototypes. The work is conceived from the beginning with standardisation, scalability, manufacturability and deployment in mind, helping to bridge the gap that often exists between research-driven prototypes and technologies that can be effectively implemented at industrial and market level.
A key point is that industry is not involved only as a supplier, but as an active driver of innovation, bringing both technological capabilities and an implementation-oriented mindset.”
WP7 aims to align technical specifications with user requirements and market needs to support commercial uptake and long-term sustainability of PM-based accelerator components. It will build a ZEPTO-PRO tuneable permanent magnet (PM), advancing technology from TRL6 to TRL7 and developing a flexible, modular, and scalable production method. It will also develop and fabricate a HF permanent magnet wiggler to enhance performance of damping ring accelerators.
This work package includes three tasks.
Task 7.1: Performance Review and Accelerator Quadrupole Specification
Review the technical progress of ZEPTO and other PM magnets built by UKRI and KYMA, assessing field strength, quality, assembly ease, and magnetic centre stability against original specifications. Strengths, shortcomings, and performance gap causes will be identified, focusing on specifications difficult to meet.
A cost analysis will highlight key cost drivers and potential savings. ZEPTO will be benchmarked against other tunable permanent magnet technologies in terms of adjustment range, assembly complexity, cost, and operational performance. Magnet designers will be engaged in a dedicated workshop to validate findings, enable objective comparisons, and foster knowledge exchange.
Specifications of existing and planned machines (aperture, gradient, quantity, adjustment needs, cost) will be reviewed to define requirements for future quadrupoles. A workshop with accelerator designers will explore the feasibility of replacing electromagnets with ZEPTO devices, defining a modular product line applicable to multiple facilities. UKRI, as the originator of ZEPTO and operator of the CLARA test facility, will contribute its expertise in both technology development and application. DESY, currently upgrading PETRA, will ensure alignment with user requirements across European accelerator facilities.
Task 7.2: Modular ZEPTO-PRO Product Line Engineering
Develop an optimised modular design for a customisable product line of tuneable ZEPTO-PRO quadrupole magnets suitable for various accelerator types. KYMA will align developments with manufacturability, cost-effectiveness, and scalable production. Potential paths for design simplification will include: a) a modular permanent magnet block holder; b) a standard approach to pole machining and shimming, which would easily correct any field errors or magnetic centre deviations; c) a set of magnet families with the same outer dimensions, regardless of central aperture; d) an assembly line and testing bench.
KYMA will deliver a ‘plug-and-play’ ZEPTO-PRO prototype device suitable for broad deployment. The processes for specification, assembly, testing, and qualification will be documented. UKRI will drive technology maturation from TRL6 to TRL7, drawing on operational feedback.
Task 7.3: Prototype HF Permanent Magnet Wiggler (PMW) for Damping Rings
Compact rings for electron and positron injection in the CERN FCC-ee will be designed using HF permanent magnets, including variable-gradient bends, quadrupoles/multipoles, and HF short period wigglers, to achieve the required beam brightness and horizontal emittance at reduced damping time with a minimal ring circumference, ensuring adequate dynamic aperture and energy acceptance to maximise positron charge. CERN will lead the damping ring design, define magnet specifications (including multipole tolerances), and conduct market and sustainability analyses, identifying technologies that require further R&D.
CIEMAT and ProactiveRD will develop the PMW design based on beam dynamics iterations to achieve the highest field at short period and a gap compatible with geometrical aperture and impedance considerations. PMW prototype will be fabricated jointly by CIEMAT and ProactiveRD according to design specifications. Partners will perform magnetic measurements, acceptance tests, and validate beam performance, enabling operational assessment and series production.