CERN Accelerating science

Published Articles
Report number	CERN-ACC-2017-200
Title	Control of Intra-Bunch Vertical Instabilities at the SPS - Measurements and Technology Demonstration
Author(s)	Fox, John (SLAC) ; Bartosik, Hannes (CERN) ; De Santis, Stefano (LBNL, Berkeley) ; Dusatko, John (SLAC) ; Höfle, Wolfgang (CERN) ; Li, Kevin (CERN) ; Métral, Elias (CERN) ; Rivetta, Claudio (SLAC) ; Salvant, Benoit (CERN) ; Turgut, Ozhan (SLAC) ; Wehrle, Urs (CERN)
Publication	2017
Number of pages	3
In:	8th International Particle Accelerator Conference, Copenhagen, Denmark, 14 - 19 May 2017, pp.TUPIK119
DOI	10.18429/JACoW-IPAC2017-TUPIK119
Subject category	Accelerators and Storage Rings
Abstract	We present recent measurements demonstrating control of unstable beam motion in single bunch and bunch train configurations at the SPS. The work is motivated by anticipated intensity increases from the LIU and HL-LHC upgrade programs, and has included the development of a GHz bandwidth reconfigurable 4 GS/S signal processor with wideband kickers and associated amplifiers. The system was operated at 3.2GS/s with 16 samples across a 5 ns RF bucket (4.2 ns bunch at injection). The experimental results confirm damping of intra-bunch instabilities in both Q20 and Q26 optics configurations for intensities of 2x10¹¹ P/bunch. Instabilities with growth times of 200 turns are well-controlled from injection, consistent with the achievable gains for the 2 installed stripline kickers with 1 kW broadband power. Measurements from multiple studies in single-bunch and bunch train configurations show achieved damping rates, control of multiple intra-bunch modes, behavior of the system at injection and final damped noise floor. We present an analysis method to study the relative phase of slice motion during a transient to discriminate between TMCI and other types of Head-Tail instabilities.
Copyright/License	CC-BY-3.0

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