Verbundprojekt R & D Beschleuniger: Verbesserung von SRF Resonatoren durch Oberflächenbehandlung einschließlich mechanischer Politur und thermischer Behandlung mit Stickstoff

Project period:
1.7.2015 - 30.6.2018

Project Coordinator:
Humboldprofessor Dr. Brian Foster

Partners of the cluster:
University of Hamburg, Institute for Experimental Physics, 22761, Hamburg
       Principal investigator: Prof. Dr. Brian Foster

Technical University of Darmstadt, Group "Advanced Thin Film Technology" (ATFT), 64287 Darmstadt
       Principal investigator: Prof. Dr. Lambert Alff

University of Rostock (UROS), Faculty of Computer Science and Electrical Engineering, Institute of General Electrical Engineering, 18059 Rostock
       Principal investigator: Prof. Dr. Ursula van Rienen

University of Wuppertal (BUW), School of Mathematics and Natural Sciences, Physics Department, 42097 Wuppertal
       Principal investigator: Prof. Dr. Günter Müller

European Organization for Nuclear Research (CERN), CH-1211 Geneva 23, Switzerland
       Principal investigator: Dr.-Ing. Erk Jensen

Deutsches Elektronen-Synchrotron (DESY), 22607 Hamburg
       Principal investigator: Prof. Dr. Eckhard Elsen

Helmholtz-Zentrum Berlin (HZB) für Materialien und Energie GmbH, 12489 Berlin
       Principal investigator: Prof. Dr. Jens Knobloch

Superconducting Radio Frequency (SRF) accelerating cavities are rapidly becoming the dominant technology for the acceleration of particles with energies beyond around 1 GeV. Their use is widespread in many research fields, from particle physics to structural biology and medicine. There are many reasons for this, including the low losses compared to conventional “warm” copper cavities, the ability to accelerate at very high repetition rate (CW) because of the very high quality factor (Q) of the cavities, their reliability and robustness and the very significant reduction in cost achieved in recent years by, among others, the Tesla Technology Collaboration (TTC). The construction of the European X-ray Free Electron Laser (EXFEL) at DESY in Hamburg has pushed the industrialisation of 1.3 GHz Niobium SRF cavities in order to produce the quantities necessary at an affordable price. That this process has been successful is shown by the beginning of installation inside the EXFEL tunnel and the rapid turn on of industrial cavity production by two manufacturers to the foreseen delivery rate.
The present collaboration network (Verbund) aims to exploit this rapid increase in interest in SRF cavities and the large numbers being produced in industry to make further progress in improving their performance in terms both of Q and accelerating gradient. This will further reduce the cost per GeV of acceleration and make the technology even more attractive for future facilities as well as for upgrades of the Large Hadron Collider (LHC) at CERN. In particular, the next major project in particle physics beyond the LHC, as agreed by all the regional “road-maps” produced in the last two years, is the International Linear Collider. This aims in its initial stage to accelerate electrons and positrons and collide them at centre-of-mass energy up to 500 GeV. Recent interest in Japan to be the host site for this accelerator, which could only be built as a world-wide collaboration, means that there is a great deal of activity throughout the world aimed at increasing the performance and cost-effectiveness of SRF cavities. Nevertheless, it is widely accepted that the current world centre for this technology is in Germany, at DESY and associated institutes. The availability of large quantities of cavities for the EXFEL in Hamburg, together with the ability to test a fraction of them, provided by the EU-funded ILC-HiGrade project, without worrying about compromising their performance, gives a unique opportunity to make speedy progress in improving their performance. The project proposed by the University of Hamburg will build strongly on the foundations provided by the previous BMBF-supported project “SRF Cavities für den ILC und andere zukünftige Beschleuniger” within the Verbundprojekt 05H2012 - R&D Beschleuniger (Supraleitende Hochfrequenztechnik).