CERN Accelerating science

Thesis
Report number	CERN-THESIS-2022-070
Title	Optimising the present and designing the future: a novel SPS injection system
Author(s)	Waagaard, Elias Walter (Uppsala University (SE))
Publication	50.
Thesis note	Master : Uppsala U. : 2022-06-15
Thesis supervisor(s)	Velotti, Francesco ; Ziemann, Volker
Note	Presented 09 Jun 2022
Subject category	Accelerators and Storage Rings
Accelerator/Facility, Experiment	CERN SPS
Abstract	The Super Proton Synchrotron (SPS) injection system plays a fundamental role to preserve the quality of injected high-brightness beams for the Large Hadron Collider (LHC) physics program and to maintain the maximum storable intensity. The present system is the result of years of upgrades and patches of a system not conceived for such intensities and beam qualities. In this study, we first investigate the effect of emittance growth due to amplitude-dependent tune shifts for erroneously injected beams. As a next step, we propose the design of a completely new injection system for the SPS using multi-level numerical optimisation, including realistic hardware assumptions. Methods and pseudo-algorithms of how this hierarchical optimisation framework can be adapted to other situations for optimal accelerator system design are shown. In addition, we explore the benefits of a numerical optimisation framework for the current SPS injection kicker timing system to minimise residual injection oscillations for maximised delivered beam intensity. We also demonstrate how a simple neural network based upon recorded data can approximate the injection system as a surrogate model, allowing for further studies of different optimisation algorithms even without beam time.

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