TUNING AND TESTING OF THE PROTOTYPE UNDULATOR FOR THE EUROPEAN XFEL

The European X-ray Free Electron Laser (EXFEL) uses three undulator systems with a total magnetic length of 455 meters. There are 91 undulator segments each 5m long. They are gap variable use planar hybrid undulator technology. They are currently in production. During the next 2.5 years they will be measured and tuned so that their field complies with the EXFEL specifications. In order to meet the tight schedule and to reach the high specifications, fast and reliable measurement methods and fine tuning algorithms have been developed and tested so that they can be used for the mass production. In this paper a short description is given. First results of the magnetic tuning preformed on some of the pre-series undulator prototypes, which were built during the past 18 months are given. It is shown that the field quality satisfies all the specifications of the European XFEL. It is also shown that the measurement and tuning process is fairly fast and straightforward to apply.