Author: Lampridis, D.
Paper Title Page
THBR01 Renovation of the Trigger Distribution in CERN’s Open Analogue Signal Information System Using White Rabbit 839
  • D. Lampridis, T. Gingold, A. Poscia, M.H. Serans, M.R. Shukla, T.P. da Silva
    CERN, Geneva, Switzerland
  • D. Michalik
    Aalborg University, Aalborg, Denmark
  The Open Analogue Signal Information System (OASIS) acts as a distributed oscilloscope system that acquires signals from devices across the CERN accelerator complex and displays them in a convenient, graphical way. Today, the OASIS installation counts over 500 multiplexed digitisers, capable of digitising more than 5000 analogue signals and offers a selection of more than 250 triggers for the acquisitions. These triggers are mostly generated at a single central place and are then distributed by means of a dedicated coaxial cable per digitiser, using a "star" topology. An upgrade is currently under way to renovate this trigger distribution system and migrate it to a White Rabbit (WR) based solution. In this new system, triggers are distributed in the form of Ethernet messages over a WR network, allowing for better scalability, higher time-stamping precision, trigger latency compensation and improved robustness. This paper discusses the new OASIS trigger distribution architecture, including hardware, drivers, front-end, server and application-tier software. It then provides results from preliminary tests in laboratory installations.  
slides icon Slides THBR01 [2.229 MB]  
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About • Received ※ 09 October 2021       Accepted ※ 21 December 2021       Issue date ※ 06 February 2022  
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THBR02 White Rabbit and MTCA.4 Use in the LLRF Upgrade for CERN’s SPS 847
  • T. Włostowski, K. Adrianek, M. Arruat, P. Baudrenghien, A.C. Butterworth, G. Daniluk, J. Egli, J.R. Gill, T. Gingold, J.D. González Cobas, G. Hagmann, P. Kuzmanović, D. Lampridis, M.M. Lipiński, S. Novel González, J.P. Palluel, M. Rizzi, A. Spierer, M. Sumiński, A. Wujek
    CERN, Geneva, Switzerland
  The Super Proton Synchrotron (SPS) Low-level RF (LLRF) system at CERN was completely revamped in 2020. In the old system, the digital signal processing was clocked by a submultiple of the RF. The new system uses a fixed-frequency clock derived from White Rabbit (WR). This triggered the development of an eRTM module for generating very precise clock signals to be fed to the optional RF backplane in MTCA.4 crates. The eRTM14/15 sandwich of modules implements a WR node delivering clock signals with a jitter below 100 fs. WR-clocked RF synthesis inside the FPGA makes it simple to reproduce the RF elsewhere by broadcasting the frequency-tuning words over the WR network itself. These words are received by the WR2RF-VME module and used to produce beam-synchronous signals such as the bunch clock and the revolution tick. This paper explains the general architecture of this new LLRF system, highlighting the role of WR-based synchronization. It then goes on to describe the hardware and gateware designs for both modules, along with their supporting software. A recount of our experience with the deployment of the MTCA.4 platform is also provided.  
slides icon Slides THBR02 [0.981 MB]  
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About • Received ※ 12 October 2021       Revised ※ 24 October 2021       Accepted ※ 03 January 2022       Issue date ※ 28 February 2022
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