Synchrotron radiation is emitted from a bending magnet source in a wide ray fan which is collected by the first optical element in a beamline. In order to maximize angular acceptance, and hence flux, it is beneficial to increase the length of this mirror and optical design requirements may necessitate that the optical surface be over 1 m in length. Such mirrors also require cooling as they may be subject to high heat loads from the incident radiation. Two beamlines, B07 and B24, at Diamond Light Source, UK, use 1.4 m long toroidal mirrors which utilize a similar side-clamped cooling manifold design. While this scheme has been successful in providing effective cooling of the mirror, it has also been discovered that it introduces deformation of the radius of curvature which is sufficient to alter the focusing characteristics of the mirror. At both beamlines, the horizontal focus of the beam was found to differ by up to several meter from the design position at the exit slit which resulted in poor flux throughput, reduced energy resolution and other side effects. A pencil beam scan method has been used to diagnose this issue and infer the position of the focus and mirror shape. Through the use of a standalone chiller to alter the temperature of the water within the cooling loop, it has been possible to correct the distortion of the radius and restore the focus to its nominal position.

Systematic studies of the performance of a water-cooled X-ray monochromator, designed and built for the B16 Test beamline at the Diamond Light Source, UK, are presented. A technical description of the monochromator is given and the results of commissioning measurements are discussed. Overall, the monochromator satisfies the original specifications well and meets all the major requirements of the versatile beamline. Following its successful implementation on B16, the basic monochromator design has been reproduced and adapted on other Diamond Light Source beamlines, including B18 and B21.

Accurate generation of small angles is of vital importance for calibrating angle-based metrology instruments used in a broad spectrum of industries including mechatronics, nano-positioning, and optic fabrication. We present a novel, piezo-driven, flexure device capable of reliably generating micro- and nanoradian angles. Unlike many such instruments, Diamond Light Source's nano-angle generator (Diamond-NANGO) does not rely on two separate actuators or rotation stages to provide coarse and fine motion. Instead, a single Physik Instrumente NEXLINE "PiezoWalk" actuator provides millimetres of travel with nanometre resolution. A cartwheel flexure efficiently converts displacement from the linear actuator into rotary motion with minimal parasitic errors. Rotation of the flexure is directly measured via a Magnescale "Laserscale" angle encoder. Closed-loop operation of the PiezoWalk actuator, using high-speed feedback from the angle encoder, ensures that the Diamond-NANGO's output drifts by only ∼0.3 nrad rms over ∼30 min. We show that the Diamond-NANGO can reliably move with unprecedented 1 nrad (∼57 ndeg) angular increments over a range of >7000 μrad. An autocollimator, interferometer, and capacitive displacement sensor are used to independently confirm the Diamond-NANGO's performance by simultaneously measuring the rotation of a reflective cube.

A laser Fizeau interferometer system has been developed to characterize the figure error of large synchrotron X-ray mirrors using double-pass geometry. This opto-mechanical assembly comprises integrated rotation and translation stages to control: the output angle of the Fizeau interferometer; the surface normal of the optic under test; and the orientation of a high quality (lambda/100) retro-reflector. To negate the effects of gravitational deformations, the system can measure long optics (up to 1.5m in length) in the geometry (sideward, downward, or upward facing) in which they will ultimately be used on a synchrotron beamline. The system has been designed to minimize environmental noise and enable the measurement geometry to be changed quickly and safely. Compared to complementary techniques, including slope profilers such as the Diamond-NOM, surface height data from the Fizeau system can be obtained more rapidly (< 1 minute). This makes the technique ideally suited to investigate the many degrees of freedom of adaptive optics, including piezo bimorph mirrors. The shape of such optics can also be monitored in real time to observe the dynamic effects of the surface in response to applied voltages. Results are presented to illustrate system performance, including repeatability levels. Calibration of the reference surfaces and the required environmental conditions are also discussed.

The Diamond-NOM is a non-contact, slope measuring profiler, capable of measuring surface topography of large optics (up to 1.5m long) with sub-nanometre height resolution and repeatability. On numerous occasions, the Diamond-NOM has proven to be an invaluable metrology tool for independently validating new beamline optics, and for investigating potential problems with optics from established beamlines. Data from the Diamond-NOM have consistently been in close agreement with results generated by a range of metrology instruments at other synchrotron laboratories and optic manufacturers. Prior to beamline installation, significant X-ray commissioning time was saved by optimizing and calibrating adaptive optics using the Diamond-NOM. We report on the current operational capabilities of the Diamond- NOM and give technical details of recent upgrades, including a penta-mirror (two, high grade reflectors used to mimic the internal working surfaces of a traditional pentaprism) and the capability to measure optics in sideward, downward, or upward facing geometries.