Accelerators 2023

6 | Introduction Introduction | 7 Furthermore, DESY is not only a significant driver of scien- tific progress, but it also has an economic impact as an employer and through the commissioning of commercial companies. Delivering high-quality electron beams at high availability is key to the success of our accelerator facilities. When PETRA III went into operation at DESY in 2010, it was the world’s most powerful X-ray source at the time. Since then, it has been generating unique scientific findings and fur- nishing essential data for innovative developments. More than 3500 researchers carry out their experiments here every year, somewhat more than half of them from Ger- many. Converting the facility into PETRA IV will ensure that it continues to meet the constantly increasing require- ments and growing demand for non-destructive nanoscale analyses in the future. Once completed, PETRA IV will be an anchor facility for the Science City Hamburg Bahrenfeld and the world’s most powerful X-ray source. This upgrade is essential for Germany and Europe as a centre for science and innovation in order to be internationally competitive in a wide range of technologies. Important developments pursued on both the accelerator and the free-electron laser (FEL) sources of the European XFEL have yielded record FEL photon energies and inten- sities. One highlight in 2023 was the demonstration of single-spike lasing with high intensities at the SASE2 undu- lator by shaping the electron beam through self-fields and detuning of the deflection arc optics. Preparations are under way to upgrade the accelerator to continuous-wave or high-duty-cycle operation, with a conceptual design expected by 2027. DESY is developing an all-supercon- ducting photoinjector for this purpose. In 2023, a break- through test demonstrated successful high-gradient operation with a copper cathode, advancing this effort. After the first phase of the FLASH2020+ upgrade and the replacement of the two oldest accelerator modules with two freshly refurbished modules, the FLASH FEL facility was routinely operated in 2023 with an energy gain of I have now been working at DESY for more than five years as Director of the Accelerator Division. DESY’s accelerators are important instruments for science in the service of society, and outstanding specialists with the highest level of expertise work here. DESY has always been a pioneer in accelerator research and development, courageously set- ting new standards and enabling cutting-edge research. Reflecting on 2023, I am reminded of the many challenges we have already faced and overcome together. The resil- ience and adaptability of the DESY staff members have been remarkable, ensuring that DESY remains a beacon of scientific excellence. It is this collective spirit and shared dedication that make working at DESY so rewarding. With the impact of our user facilities and our fundamental research, we at DESY are part of the solution to the major challenges facing society. We should take the lessons learned from the pandemic to accelerate the health research of tomorrow. When Federal Minister of Health Karl Lauterbach visited DESY in June 2023, he praised the interdisciplinary work at DESY as an outstanding example of cutting-edge research in Germany. In 2023, DESY achieved significant milestones, reinforcing its status as a global leader in accelerator science and research. The progress in the PETRA IV upgrade project and the ongoing developments at our user facilities and at the European XFEL X-ray laser have been particularly inspiring. With the federal Budget Committee’s decision to fund a pre-project for the fourth-generation synchrotron radiation source PETRA IV, with co-financing by the City of Hamburg, preparatory measures can now begin, in particu- lar for the construction and prototype of an innovative, energy-saving plasma injector and for the conversion of the business model. A study carried out by the Fraunhofer Institute for Systems and Innovation Research in 2023 showed that DESY’s light source PETRA III has created 2.25 billion euros in added value. The PETRA IV upgrade could add a further 7.35 bil- lion euros in value – possibly even considerably more. 450 MeV, bringing the electron beam energy to over 1.35 GeV and pushing the photon wavelength down beyond 3.5 nm. A major milestone on the way to a seeded FLASH1 user facility, which is described in this report, was the successful demonstration of external seeding using echo-enabled harmonic generation with parallel self-ampli- fied spontaneous emission operation in the FLASH2 beam- line. The impressive results leave us excited about the future performance of the seeded FLASH1 user facility. Accelerator R&D at DESY has always been at the forefront of scientific innovation. Coming from an engineering back- ground myself, it fills me with great pride that the 2023 Bjørn H. Wiik Prize – DESY’s most important science award – went to an engineer, Julien Branlard, in recognition of his outstanding contributions to developing the low-level radio frequency systems for the stable, reliable and extremely precise operation of the linear accelerators driving the European XFEL and FLASH. In 2023, we have also deep- ened our understanding of the physics behind the tuning and optimisation of laser plasma acceleration. This further lays the foundation for applying this technology in the years to come. Another highlight of my tenure during the past five years has been witnessing the focus and successful implementa- tion of our comprehensive sustainability strategy. This ini- tiative is not just about reducing our environmental foot- print but also about innovating in ways that make our research infrastructure more efficient and resilient. Utilis- ing the waste heat from our accelerators to heat the cam- pus is a testament to our commitment to sustainability and operational excellence, and I am delighted that the Helm- holtz Association has approved funds of around 8 million Wim Leemans Director of the Accelerator Division Accelerators at DESY Introduction Figure 1 During his visit, Federal Minister of Health Karl Lauterbach commended the interdisciplinary work at DESY as an outstanding example of cutting- edge research in Germany – and of how this research directly benefits people’s healthcare. euros for the project implementation in 2023. Furthermore, our technical groups have also explored options to run our facilities in modes that reduce energy consumption, and they have successfully implemented measures that are having a significant impact. Last but not least, the DESY management and staff would like to thank Robert Feidenhans’l for his exemplary leader- ship as Chairman of the Management Board at European XFEL until the end of 2023, for his unwavering commitment to excellence and the strong partnership with DESY, in par- ticular with the Accelerator Division. We wish him all the best and every success in his future endeavours. At the same time, we warmly welcome Thomas Feurer, who has taken over as the new Chairman of the Management Board at European XFEL at the beginning of 2024, and we look forward to continuing the great collaboration with our partner institute. As we look to the future, I am excited about the possibili- ties that lie ahead. DESY’s commitment to innovation, sus- tainability and scientific leadership is unwavering. I am con- fident that we will continue to achieve great things, driven by our shared passion for discovery and excellence. Thank you to everyone who has contributed to our successes this year. Your hard work and dedication are what makes DESY a truly exceptional place to work.