Flat-bottom instabilities in the CERN SPS

Autor:	Schwarz, Markus, Iliakis, Konstantinos, Lasheen, Alexandre, Papotti, Giulia, Repond, Joël, Shaposhnikova, Elena, Timko, Helga
Jazyk:	angličtina
Rok vydání:	2019
Předmět:	MC5: Beam Dynamics and EM Fields Physics::Accelerator Physics Accelerators and Storage Rings Accelerator Physics
Popis:	At beam intensities of 2.6·10¹¹ protons per bunch, required at SPS injection for the High Luminosity LHC beam, longitudinal instabilities can degrade the beam quality delivered by the SPS, the LHC injector at CERN. In this paper, we concentrate on beam instability at flat bottom. The dependence of the instability threshold on longitudinal emittance and LLRF system settings was measured, to help identify the impedance driving this instability. While reducing the longitudinal emittance reduces the losses at injection, it can drive the beam unstable. The LLRF system of the SPS (partially) compensates beam loading, but also affects the instability. The effect of the different LLRF systems (feedback, feedforward, phase loop and longitudinal damper) and fourth harmonic RF system on the instability was investigated. The measurements are compared with simulations performed with the longitudinal tracking code BLonD. Proceedings of the 10th Int. Particle Accelerator Conf., IPAC2019, Melbourne, Australia
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_dedup___::790e2108c6a02fe75c905b6f8eaccba9 http://cds.cern.ch/record/2693533 Zobrazit plný text záznamu