Dedication for Julien Branlard, recipient of Björn H. Wiik Prize 2023

Julien Branlard receives the Björn H. Wiik Prize of 2023 in recognition of his outstanding achievements in the field of high-precision control of superconducting radio-frequency resonators, which have gained worldwide attention.

For the new Free-Electron Lasers at DESY, the acceleration fields in the electron accelerators must be set with incredible temporal accuracy. This is because the electron bunches used are only a few micrometers long. The acceleration fields must be switched on precisely at the moment the bunches arrive, meaning with a temporal accuracy of a few femtoseconds – the time it takes an electron to travel a distance of one micrometer at nearly the speed of light. At the European XFEL, 800 superconducting accelerator tubes must be controlled with this temporal precision, built along the 1 km long beam tube.

The use of superconductor technology was therefore essential, requiring the control of the radio-frequency fields to be about a thousand times faster and more precise than was previously necessary and possible. Julien Branlard's team developed a technically highly sophisticated, highly complex system, without which the European XFEL would neither achieve its beam quality nor its enormously high operational reliability. Thanks to this system, the first commissioning of the accelerator was carried out extremely quickly and efficiently.

Julien Branlard's work in the fields of simulation, software and firmware development, and µTCA technology sets an international standard and continues to lead to globally recognized developments benefiting major research facilities.