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Title: Development of a prototype cavity beam position monitor for the Compact Linear Collider
Author: Cullinan, Frankie
ISNI:       0000 0004 8497 8937
Awarding Body: Royal Holloway, University of London
Current Institution: Royal Holloway, University of London
Date of Award: 2014
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The Compact Linear Collider (CLIC) is a proposed electron positron collider with a maximum centre of mass energy of 3 TeV. In order for it to operate at its maximum luminosity, precise alignment of the accelerator elements in the main linac and beam delivery system is required. The beam based alignment algorithm designed to do this requires measurements of the transverse beam position with a resolution of 50 nm and multiple position measurements within a single 156 ns long bunch train. The proposed solution is a cavity beam position monitor (BPM) with a low quality factor. A prototype cavity BPM pick-up has been designed and manufactured for tests on the probe beamline of the third CLIC test facility (CTF3) at the European Organisation for Nuclear Research (CERN). This thesis presents the measurements performed on this prototype in the laboratory, the development of the associated processing electronics and tests with beam. The resonant frequencies and quality factors of the modes of interest in the two cavities of the prototype BPM pick-up were measured in the laboratory using a network analyser. Problems with the design of the pick-up geometry are identified and solutions proposed. Analytical expressions for the amplitude and phase and total energy of the multiple bunch signals are derived and a processing algorithm for the deconvolution of the single bunch waveform from the multiple bunch signal is presented. A set of receiver electronics for analogue processing of the microwave frequency signals has been designed and built from connectorised components. Beam-based measurements of the sensitivity of the position cavity signal to beam position and the reference cavity signal to charge have been made. The cavity BPM has been calibrated and used to measure the beam position jitter at the BPM location. Finally, the performance of the whole system is discussed and possible tests that could be used to determine the measurement bandwidth of the cavity BPM are proposed.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available