Prototype X-ray source and monochromator for X-ray photoelectron spectrometry.

The project will produce a prototype X-ray source and monochromator for use in X-ray
photoelectron spectroscopy (XPS). XPS is a surface analysis technique that uses X-rays to
interrogate the sample within a vacuum chamber. This prototype source will incorporate Torr
Scientific Ltd’s (TSL) existing diamond-tipped anode technology, but will have novel
geometry and
use of materials to produce a focused, monochromated X-ray spot of superior performance.
Modern XPS systems use monochromated X-rays occupying a narrow wavelength band. This
delivers detailed chemical information unavailable with a non-monochromated source.
Confining the X-rays to a small spot on the sample allows more precise spatial analysis of the
sample, but tends to give less signal, increasing the analysis time. This means that the small
spot capabilities on many systems are rarely used. The novel monochromator geometry in the
prototype system will give more efficient X-ray harvesting and more power in a small spot
than other systems. This will provide a uniquely useful small spot capability.
Existing technology dictates that the source and monochromator are attached externally to the
sample chamber via a series of vacuum ports. This occupies an external volume that is often
comparable to that of sample chamber. Competing demands for space mean that
monochromated X-ray sources are usually designed specifically for a given XPS system, and
the scope for substituting a new source is limited. There are very few retrofittable small spot
sources on the market.
The novel geometry of the new prototype will mean that its source and monochromator are
housed largely within the existing vacuum chamber, and attachment is achieved by means of a
single vacuum port. Its minimal external footprint means that it can be accommodated by the
vast majority of existing systems, even older or more basic systems upgrading from a non
monochromated, non-small spot source.