The Joint Accelerator Conferences Website (JACoW) is an international collaboration that publishes the proceedings of accelerator conferences held around the world.
TY - CONF AU - Galindo Guarch, F.J. AU - Baudrenghien, P. AU - Moreno Arostegui, J.M.M.A. ED - Koscielniak, Shane ED - Satogata, Todd ED - Schaa, Volker RW ED - Thomson, Jana TI - Compensation of Transient Beam Loading in Ramping Synchrotrons Using a Fixed Frequency Processing Clock J2 - Proc. of IPAC2018, Vancouver, BC, Canada, April 29-May 4, 2018 C1 - Vancouver, BC, Canada T2 - International Particle Accelerator Conference T3 - 9 LA - english AB - Transient beam loading compensation schemes, such as One-Turn-FeedBack (OTFB), require beam synchronous processing (BSP). Swept clocks derived from the RF, and therefore harmonic to the revolution frequency, are widely used in CERN synchrotrons; this simplifies implementation with energy ramping, where the revolution frequency changes. It is however not optimal for state-of-the-art digital hardware that prefers fixed frequency clocks. An alternative to the swept clocking is the use of a deterministic protocol, for example, White Rabbit (WR): a fixed reference clock can be extracted from its data stream, while enabling digital distribution of the RF frequency among other data. New algorithms must be developed for BSP using this fixed clock and the digital data transmitted on the WR link. This is the strategy adopted for the SPS Low Level RF (LLRF) upgrade. The paper gives an overview of the technical, technological and historical motivations for such a paradigm evolution. It lists the problems of fixed clock BSP, and presents an innovative solution based on a real-time variable ratio re-sampler for implementing an OTFB with the new fixed clock scheme. PB - JACoW Publishing CP - Geneva, Switzerland SP - 4957 EP - 4960 DA - 2018/06 PY - 2018 SN - 978-3-95450-184-7 DO - 10.18429/JACoW-IPAC2018-THPML121 UR - http://jacow.org/ipac2018/papers/thpml121.pdf ER -