Successful industrial consultancy between Diamond Light Source and FMB Oxford

A successful industrial consultancy between Diamond Light Source and FMB Oxford Ltd has developed mechanical systems that can accurately bend long X-ray mirrors to a range of useful ellipses.

Grazing incidence X-ray mirrors are used extensively at all synchrotron radiation (SR) and free electron laser (FEL) facilities to focus or align intense photon beams used for scientific research. At Diamond Light Source the beamlines can be configured to suit the variety of experimental requirements across the diversity of scientific areas and applications. Active optics with transformable reflective surfaces, such as piezo bimorph deformable mirrors or mechanically bent mirrors, enable focusing parameters of the beamline to be easily and quickly adjusted. At SR sources and FELs, the quality of X-ray optics is often a major limitation to beamline performance. Guided by advances in optical and X-ray metrology, deterministic polishing techniques such as ion beam figuring and elastic emission machining can now routinely fabricate long X-ray mirrors with low slope errors (< 200 nanoradians (nrad) root-mean-square). These advances have greatly improved the quality of optical surfaces but have revealed a new challenge for X-ray optics: minimising additional slope errors introduced by mounting the substrate into its holder, adding cooling manifolds, and bending it.


High quality metrology instruments and ultra-stable environments are essential to aid optimisation of clamping and bending to guarantee the best possible X-ray performance for beamline optics. Ex-situ optimisation and fault-finding investigations of such systems prior to beamline installation have saved significant amounts of valuable X-ray commissioning time, and it is here where the testing capabilities of the Optics and Metrology group at Diamond come into play. Commercial suppliers of synchrotron optical systems can benefit from Diamond’s state-of-the-art metrology instruments and facilities that enable testing to unprecedented levels. On several occasions, FMB Oxford have successfully exploited this metrology service, including the recent tests of their newly developed 2-moment actuator systems for elliptical bending of long X-ray mirrors which have just been published in Journal of Synchrotron Radiation.

Quote from Simon Alcock – Senior Metrology Scientist, Diamond Light Source:

“Over many years we’ve developed a cleanroom lab with metrology instruments of exceptional accuracy which are capable of characterising state-of-the-art X-ray optics. Aside from acceptance testing of all Diamond’s optics, in recent years we’ve also begun offering a paid commercial service to manufacturers, including FMB Oxford, to characterise and optimise beamline optical systems on behalf of other synchrotrons. Diamond’s enhanced metrology capabilities provide manufactures with a two-fold advantage: helping to improve the quality of their products, and to provide an independent verification of high quality”

Quote from FMB Oxford:

“With the arrival of Diffraction Limited Storage Rings and FELs as the latest generation of x-ray sources offering smaller sizes and greater stability, it has been the challenge of beamline optical systems to follow the associated requirements for near-perfect shape (in the single digit nm range) and immunity to vibration and drift.  Ready commercial access to the broad range of capabilities at the Diamond Metrology group has been one of the most important parameters shaping our successful progress in that journey.  It is more than simply the extensive suite of instruments, it is the team’s unquestioning willingness to work collaboratively, to identify opportunities and to drive towards achieving the goal at hand that has lead us to come back again and again.”

Read the complete paper here:

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