I joined ASTeC (link opens in a new window) in October 2005, following the completion of my Ph.D. research in the field of spin-resolved electron spectroscopy. I apply my practical research and experimental skills to working in support of the ALICE (link opens in a new window) DC photocathode electron gun and its drive laser where I have responsibilities for photoinjector drive laser tuning and maintenance, photocathode preparation, activation and performance/lifetime studies. I also provide laser support for the VELA (link opens in a new window) RF electron gun which uses a metal photocathode.
I played a key role in the design and development of a Photocathode Preparation Facility (PPF) which was part of a planned upgrade to the existing ALICE photocathode electron gun. The use of a PPF external to the gun significantly improves gun performance by separating the ‘chemistry’ of GaAs photocathode activation from the high-voltage, extreme high vacuum environment of the photocathode gun itself. Furthermore, the ability to rapidly exchange photocathodes confers a significant operational advantage to an accelerator facility.
I have developed equipment and software to characterise the transverse energy spread of photocathode electron sources, this being a key limiting factor in photocathode performance. The Transverse Energy Spread Spectrometer (TESS) was commissioned recently using GaAs photocathodes prepared in the PPF, with assistance from the Institute of Semiconductor Physics (link opens in a new window) (Novosibirsk, Russia) as part of a long-standing collaboration.
A series of experiments on GaAs and other III-V group photocathodes is planned to investigate transverse energy spread at both room and cryogenic temperatures, and with varying levels of quantum efficiency. The primary aim is to gain an understanding what drives the transverse energy spread, and how this quantity can be minimised to improve electron beam quality . The TESS equipment has wide general applicability, and will ultimately support research into semiconductor, multi-alkali and metal photocathode performance.
I contribute to ASTeC’s metal photocathode R&D programme through the provision of light sources and advice on optics and delivery systems. I am currently designing and assembling a portable UV laser system with the requisite safety systems to enable research on metal photocathodes, and ultimately their performance characterisation in the TESS system.
I have collaborative links with the IR-FEL (link opens in a new window) and CEBAF (link opens in a new window) injector groups at Jefferson Laboratory (link opens in a new window) , and with the ERL injector group at Cornell University (link opens in a new window) , both located in the United States. I also have responsibilities for outreach and public engagement activities on behalf of ASTeC (link opens in a new window) and the Cockcroft Institute (link opens in a new window) .