Author: Butkowski, L.     [Butkowski, Ł.]
Paper Title Page
MOPGF093 Real-time Beam Loading Compensation for Single SRF Cavity LLRF Regulation 1
  • I. Rutkowski, M. Grzegrzólka
    Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
  • Ł. Butkowski, Ch. Schmidt
    DESY, Hamburg, Germany
  • M. Kuntzsch
    HZDR, Dresden, Germany
  Stable and reproducible generation of a photon beam at Free Electron Lasers (FELs) necessitates a low energy spread of the electron beam. A low level radio frequency (LLRF) control system stabilizes the RF field inside accelerating modules. An electron beam passing through the cavity induces a drop in the actual stored field proportional to the charge, the cavity shunt impedance, and the bunch repetition rate. The feedback loop compensates for the perturbation after the accelerating gradient drops. Due to the digital loop delay and limited bandwidth of the closed loop system, this disturbance induces control errors which can increase beam energy spread. An open-loop controller uses information obtained from the beam diagnostic systems accounting in real-time for fluctuations of the beam current. This paper describes the bunch charge detection scheme, its implementation, as well as results of the tests performed on the ELBE (Electron Linac for beams with high Brilliance and low Emittance) radiation source at the HZDR (Helmholtz-Zentrum Dresden-Rossendorf) facility.  
poster icon Poster MOPGF093 [4.046 MB]  
WEPGF029 High Level Software Structure for the European XFEL LLRF System 1
  • Ch. Schmidt, V. Ayvazyan, J. Branlard, Ł. Butkowski, O. Hensler, M. Killenberg, M. Omet, S. Pfeiffer, K.P. Przygoda, H. Schlarb
    DESY, Hamburg, Germany
  • W. Cichalewski, F. Makowski
    TUL-DMCS, Łódź, Poland
  • A. Piotrowski
    FastLogic Sp. z o.o., Łódź, Poland
  The Low level RF system for the European XFEL is controlling the accelerating RF fields in order to meet the specifications of the electron bunch parameters. A hardware platform based on the MicroTCA.4 standard has been chosen, to realize a reliable, remotely maintainable and high performing integrated system. Fast data transfer and processing is done by field programmable gate arrays (FPGA) within the crate, controlled by a CPU via PCIe communication. In addition to the MTCA system, the LLRF comprises external supporting modules also requiring control and monitoring software. In this paper the LLRF system high level software used in E-XFEL is presented. It is implemented as a semi-distributed architecture of front end server instances in combination with direct FPGA communication using fast optical links. Miscellaneous server tasks have to be executed, e.g. fast data acquisition and distribution, adaptation algorithms and updating controller parameters. Furthermore the inter-server data communication and integration within the control system environment as well as the interface to other subsystems are described.  
WEPGF074 FPGA Firmware Framework for MTCA.4 AMC Modules 1
  • Ł. Butkowski, T. Kozak, B.Y. Yang
    DESY, Hamburg, Germany
  • P. Prędki
    TUL-DMCS, Łódź, Poland
  • R. Rybaniec
    Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
  Many of the modules in specific hardware architectures use the same or similar communication interfaces and IO connectors. MicroTCA (MTCA.4) is one example of such a case. All boards: communicate with the central processing unit (CPU) over PCI Express (PCIe), send data to each other using Multi-Gigabit Transceivers (MGT), use the same backplane resources and have the same Zone3 IO or FPGA mezzanine card (FMC) connectors. All those interfaces are connected and implemented in Field Programmable Gate Array (FPGA) chips. It makes possible to separate the interface logic from the application logic. This structure allows to reuse already done firmware for one application and to create new application on the same module. Also, already developed code can be reused in new boards as a library. Proper structure allows the code to be reused and makes it easy to create new firmware. This paper will present structures of firmware framework and scripting ideas to speed up firmware development for MTCA.4 architecture. European XFEL control systems firmware, which uses the described framework, will be presented as example.  
poster icon Poster WEPGF074 [0.702 MB]