Photocathodes for the Generation of High-Brightness Electron Beams

The highest levels of electron beam quality are obtained using a photoemission based electron source or photoinjector, which is a photocathode electron source emitting into an accelerating electric field. Alkali metal and thin film photocathodes are ideal candidates for these applications as they demonstrate high levels of quantum efficiency (QE) and good operational lifetime, thus permitting long uninterrupted periods of user exploitation. The high levels of QE gives additional headroom in respect of illumination laser power to facilitate transverse and longitudinal laser pulse shaping, and thus maximise the electron beam brightness and quality.

This project will focus on development of techniques to manufacture high-performance thin-film photocathode electron sources for particle accelerators, modifying and expanding the deposition equipment and processes as necessary. The use of surfaces modified by techniques such as ion implantation will also be investigates. The goal is to identify the optimum materials and preparation techniques to achieve the highest levels of electron beam brightness, with the lowest intrinsic emittance and the longest operational lifetime.

The project will also continue the development and exploitation of the TESS Transverse Energy Spread Spectrometer for the characterisation of novel photocathode electron source materials.

In the first year of the project, you will be familiarised with the existing surface analysis and photocathode growth equipment, and the TESS used to characterise photocathode electron sources, and contribute to the commissioning of the new alkali metal photocathode growth facility. In subsequent years, you will focus on the growth and characterisation of photocathode sources with different compositions, seeking an optimum deposition solution, identifying new/improved electron sources, and publishing results wherever possible.

The work will take place predominantly at Daresbury Laboratory, mostly involving laboratory-based studies of photoemissive materials in our state-of-the-art VISTA2 laboratory. There will also be the opportunity to use other research facilities within the lab to further characterise these materials to investigate ultimate beam brightness achievable. The project gives excellent opportunities for high quality publications and for presenting results at national and international research workshops and conferences.

You will have access to the Cockcroft Institute’s unique postgraduate training in accelerator science and technology, consisting of lectures, seminars and on-campus workshops. You will be working within the Accelerator Science and Technology Centre (ASTeC) and be part of the pen-European QUASAR Group. The studentship will be paid for up to 42 months at standard RCUK level. 

Supervisors: Prof Carsten Welsch, c.p.welsch@liverpool.ac.uk , Dr Lee Jones, ASTeC/STFC

Applying: https://www.liverpool.ac.uk/study/postgraduate-research/how-to-apply/ Please ensure you quote the following reference on your application: PPPR031 - Photocathodes for the Generation of High-Brightness Electron Beams