New concept for the ring’s magnets
Within the PETRA IV project, Wim Leemans, Director of DESY’s Accelerator Division, is responsible for the construction of the accelerator facilities, a task he pursues with passion and commitment. He describes the opportunities and challenges involved in selecting the magnets for PETRA IV. More than 4000 of them are needed for the accelerator ring to generate the extremely brilliant radiation.
The electromagnets are among the biggest power consumers in the accelerator ring. So PETRA IV is using a large number of permanent magnets to reduce its electricity consumption.
What are the advantages?
Permanent magnets are magnetic all the time, as the name suggests, not just when the power is switched on. Other X-ray sources, such as the ESRF in France and PSI in Switzerland, are already using this technology to save 20 to 30 per cent of the electricity needed to power their magnets.
Nevertheless, there are also some drawbacks. What is the problem?
To make permanent magnets you need rare earths and cobalt, which are often mined and processed under appalling social and environmental conditions. Because of this, DESY is actively promoting projects for recycling magnets and certifying critical raw materials. In 2023, for example, we organised a workshop to generate new ideas.
PETRA IV will be built in the existing ring tunnel of our X-ray light source PETRA III. It will be recycled, so to speak. This is also a contribution to sustainability.
