Power supply unit for ATCA-based piezo compensation system

Pulsed operation of high gradient superconducting radio frequency (SCRF) cavities results in dynamic Lorentz force detuning (LFD) approaching or exceeding the bandwidth of the cavity of order of a few hundreds of Hz. The resulting modulation of the resonance frequency of the cavity is leading to a perturbation of the amplitude and phase of the accelerating field, which can be controlled only at the expense of RF power. The X-Ray Free Electron Laser (X-FEL) accelerator, which is now under development in Deutsches Elektronen Synchrotron (DESY), will consists of around 800 cavities with a fast tuner fixture including the actuator / sensor configuration. Therefore, it is necessary to design a distributed control system which could be able to supervise around 25 RF stations, each one comprised of 32 cavities. The Advanced Telecommunications Computing Architecture (ATCA) was chosen to design, develop, and build a Low Level Radio Frequency (LLRF) controller for X-FEL. The already performed tests of ATCA LLRF control system proofed the possibilities of usage of such a standard for high energy physics experiments. The paper presents the concept of integration of the piezo compensation system to the ATCA standards with special emphasis to the hardware part of the system. Moreover, the first results from carried out tests of the prototype power supply unit for piezo drivers integrated to ATCA board will be presented.