SLAC, Menlo Park, California, USA
CERN, Geneva, Switzerland
We present the expanded system implementation and operational experience details for the “Demo” technology platform commissioned at the SPS in January 2015. The system has been expanded during the LS1 shutdown with added features. The upgraded system has enhanced performance and more robust synchronization to the beam and accelerator timing system. Central to the new features are 1 GHz bandwidth kickers and RF amplifiers (including associated equalizers) which allow excitation and control of higher modes within the 2 ns bunch. We highlight the expanded features, and present their details.
SLAC, Menlo Park, California, USA
CERN, Geneva, Switzerland
Multi-input multi-output (MIMO) feedback design techniques can be helpful to stabilize intra-bunch transverse instabilities induced by electron-clouds or transverse mode couplings at the CERN Super Proton Synchrotron (SPS). These MIMO techniques require a reduced order model of intra-bunch dynamics. We estimate a linear reduced order MIMO models for transverse intra-bunch dynamics and use these models to design model based MIMO feedback controllers. The effort is motivated by the plans to increase currents in the SPS as part of the HL-LHC upgrade. Parameters of the reduced order models are estimated based on driven beam SPS measurements. We study different types of controllers. We test the model based designs using macro particle simulation codes (CMAD and HEADTAIL) and compare its performance with FIR filters tested during beam measurements of the feedback system in SPS machine development (MD) studies.
SLAC, Menlo Park, California, USA
LBNL, Berkeley, California, USA
CERN, Geneva, Switzerland
We present experimental measurements taken from CERN SPS machine development studies with a wideband intra-bunch feedback channel prototype. The demonstration system is a digital processing system with recently installed wideband kicker and amplifier components. This new hardware extends the bandwidth up to 1GHz and allows driving and controlling multiple vertical transverse modes in the bunch. The studies are focused on both driving the bunch with spectrally controlled signals to identify a reduced model of the bunch dynamics and testing model-based feedback controllers to stabilize the bunch dynamics. The measurements are structured to validate reduced MIMO models and macro-particle simulation codes, including the dynamics and limits of the feedback channel. Noise effects and uncertainties in the model are evaluated via SPS measurements to quantify the limits of control techniques applied to stabilize the intrabunch dynamics. The design of controllers for Q26 and Q20 optics are illustrated and future control developments are described.
