Construction of a prototype ultra-high-vacuum compatible compact X-ray monochromator for use in X-ray photoelectron spectroscopy

X-ray photoelectron spectroscopy (XPS) is the primary technique employed to determine the chemical composition and chemical state of material surfaces, with an analysis depth of approximately 5 nm. For the highest quality chemical state information, the energy resolution of the acquired spectrum should be enhanced. This is achieved via the X-ray source being monochromated using single crystal diffraction. Commercial XPS instruments have a large, bulky monochromator that is external to the sample chamber, typically with a quartz crystal.

Project aims

This project aims to design and construct a compact monochromator that sits largely within the analysis chamber, lowering cost and simplifying the instrumentation for small-spot XPS analysis. This new monochromator will require novel approaches to design and materials compared to existing systems.

The project will involve deployment of the monochromator crystal in a novel way and identification of a material with more favourable diffraction characteristics than quartz. This could include micro-mechanical modification of the crystal allowing it to bend to the correct angle or superposition of small individual crystals in a novel arrangement. Alternative technological approaches will also be explored.

The new crystal design needs to be fabricated and a test facility established at Torr Scientific. A prototype design of the monochromator employing the new crystal using the chosen technology will then be developed, manufactured and assembled. Performance testing will take place on the XPS instrumentation at Surrey.

Where you will be based

This PhD is a collaboration between Torr Scientific (Bexhill-on-Sea, East Sussex) and Dr Mark Baker in the Surface Analysis Laboratory at the University of Surrey, with the student being based in the Research and Developement Department at Torr Scientific.

Candidates must meet Surrey graduate entry requirements which include holding:

• At least an upper second-class (2:1) UK honours degree or equivalent qualifications in a relevant subject area such as mechanical engineering, physics, materials science or chemistry
• A masters degree in a relevant discipline and additional research experience would be an advantage.

All candidates must be a permanent UK resident for fee purposes.