High-Speed Data Processing Module for LLRF

Abstract

Linear accelerators, like the Free-electron LASer in Hamburg (FLASH) or the European X-Ray Free Electron Laser (E-XFEL) take advantage of the digital Low Level Radio Frequency (LLRF) system to control the phase and amplitude of an electromagnetic field inside superconducting cavities. The real-time control LLRF system, processing data within a few microseconds, has to fulfil performance requirements and provide comprehensive monitoring and diagnostics. The AMC-based controller (DAMC-TCK7) board was developed as a general purpose high-performance low-latency data processing unit designed according to the PICMG MTCA.4 spec. The module provides the processing power, data memory, communication links, reference clock, trigger and interlock signals that are required in modern LLRF control systems. The module was originally designed as a cavity field stabilizing controller for standing-wave linear accelerators. However, the application of the board is much wider because it is a general purpose data processing module suitable for systems requiring low latency and high-speed digital signal processing. According to authors' knowledge this is the first MTCA.4 module offering 12.5 Gbps links, unified Zone 3 connectivity and advanced Module Management Controller proposed by DESY. The DAMC-TCK7 card was used as a hardware template for the development of the other AMC modules of the XFEL accelerator's LLRF system. This paper discusses the requirements for the digital real-time data processing module, presents the laboratory performance evaluation and verification in Cryo-Module Test Bench (CMTB) at DESY.