Juarez Lopez, David
(2021)
Characterisation of High–Performance Electron Sources for Particle Accelerators using a Transverse Energy Spread Spectrometer.
Unspecified thesis, University of Liverpool.
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Abstract
Electron beams have demonstrated to have the brightness needed to drive free–electron lasers (FEL) at X–ray wavelengths. These state-of-the-art elec- tron beams are now becoming limited by achieving a low mean transverse energy (MTE) at room and cryogenic temperatures of electrons emitted from photo–cathode–based electron sources. Reducing the MTE in an accelerator which drives a FEL delivers a significant reduction in the saturation length for an X–ray FEL, thus reducing the machine’s construction footprint and operating costs whilst increasing X–ray beam brightness. In this thesis I present in detail the commissioning of a transverse energy spread spectrometer (TESS) following substantial upgrades to this system. The commissioning work uses data for single–crystal copper photocathodes illuminated at various wavelengths supported by a comparison to predi- ctions from a sophisticated density–functional theory simulation. Additional data for single–crystal zirconium and niobium is presented at different wave- lengths and temperatures with comparison to simulation values. I also present details of the complete characterisation of a batch of al- kali metal photocathodes grown at CERN and transported to Daresbury to utilise the TESS instrument. This batch comprised three caesium tellurium and one caesium potassium antimony photocathodes grown on high–purity polycrystalline copper substrates via a co-deposition process, none of which had previously been characterised in such detail.
| Item Type: | Thesis (Unspecified) |
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| Divisions: | Faculty of Science and Engineering > School of Physical Sciences |
| Depositing User: | Symplectic Admin |
| Date Deposited: | 10 Sep 2021 10:21 |
| Last Modified: | 01 Aug 2023 01:30 |
| DOI: | 10.17638/03127323 |
| Supervisors: |
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| URI: | https://livrepository.liverpool.ac.uk/id/eprint/3127323 |
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