Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.683946
Title: Electro-optic diagnostic techniques for the CLIC Linear Collider
Author: Pan, Rui
ISNI:       0000 0004 5919 2334
Awarding Body: University of Dundee
Current Institution: University of Dundee
Date of Award: 2015
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Abstract:
One of the most promising devices to provide accurate measurement of the longitudinal bunch profile at the tens of femtosecond level is based on electro-optic techniques. In this thesis, a bunch profile monitor, based on electro-optic spectral decoding (EOSD), is currently developed for the CLIC Test Facility 3 at CERN. The monitor is optimised for bunch lengths over 3.5 ps with effective window of 16 ps, and sub-picosecond resolution. The measurement results from the EO monitor are compared with measurements by coherent transition radiation on a streak camera. The measurement on bunch charge dependence is studied. Timing resolution of the bunch profile monitor is studied in both theory and numerical calculation. This thesis summarises a frequency analysis approach of electro-optic effect based on $\chi^{(2)}$ frequency mixing process. From the theory analysed in frequency domain, a non-crossed polarization measurement includes all three of the probe laser background term, the linear term to Coulomb field and the quadratic term to Coulomb field. Three methods are induced based on this frequency analysis result to retrieve Coulomb field value which is emitted from electron beam. The measured 1.3 MV/m field strength agrees with calculation result. An experiment is designed to study the role of incident beam sizes and non-collinear incident beams in EO technique. Due to the phase matching process, the non-collinear angle of the incident beams induces a frequency dependent angular chirp in the beams emitted after the EO crystal. This frequency offset may lead to frequency loss in fibre coupling, and thus lead to bunch length broadening in a measurement for short electron bunch.
Supervisor: Lefevre, Thibaut ; Jamison, Steven P. Sponsor: CERN
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.683946  DOI: Not available
Keywords: Linear accelerator ; Bunch profile measurement ; Electro-optic ; Ultrafast laser ; THz
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