In the frame of the LEAPS-Innov pilot project, the ESRF together with ALBA, Soleil, PTB and HZB have developed a position measuring system based on fibered laser interferometers and beam steering mirrors that track the position of the object to be measured thanks to a closed loop control system. The global objective is to measure the position of objects moving in a plane along 3 degrees of freedom (2 translations and one rotation), with a typical range of a few millimeters and a few tens of degrees and with a repeatability of 10 nanometers. This system could typically be used for measuring sample position in experimental stations. The project was divided in 2 parts, the first one being dedicated to the characterization of periodic non linearities of commercially available fibered interferometers by all project partners and continued with the design and construction of a 3 axes prototype system at ESRF. I will present the results of the interferometers characterization, the design of the mechanical, optical and control systems used to implement this prototype and the experimental results obtained.

This contribution provides an insight into the X-ray Free Electron Laser Oscillator (XFELO), an R&D project currently under commissioning at the European XFEL. XFELO aims to be the first demonstrator of a cavity-based free electron laser, promising significantly enhanced beam properties. The layout of the optical cavity and its integration into the SASE1 undulator section present unique challenges, particularly regarding the optomechanics to align the individual optical elements. These requirements include two angular and two linear degrees of freedom (DoF) with nanoradian-level angular stability and resolution, long travel ranges of up to 40 mrad, ultra-high vacuum compatibility, non-magnetic materials, and radiation resistance. To meet these demands, high-precision mechanics were developed that are based on flexures and combine parallel kinematics for high-resolution angular alignment with integrated serial kinematics for linear positioning. We will provide an overview of the XFELO setup, followed by a detailed look at the design and implementation of the precision mechanics. Finally, we will present a brief summary of the current status of commissioning and performance.

The Precision Metrology Laboratory (PML) at Diamond Light Source provides an ultra-stable environment and specialist instrumentation to perform micro- and nano-scale dimensional metrology to support beamline operation. The lab enclosure is actively stabilised to 10 mK RMS in temperature and 0.5 %RH RMS in humidity. Under these conditions, sub-nm displacements have been measured using capacitive sensor and linear interferometers, and sub-nrad angles have been measured using autocollimator and angle interferometers$*$. Such measurement capabilities are required to characterise and enhance the performance of positioning systems for sample, optics, and detectors on the beamlines. This philosophy has frequently helped to identify faults prior to installation, including misalignments, parasitic motion errors, and controller issues, thereby saving a significant amount of X-ray commissioning time. Increasingly, the PML is involved in the prototyping of new beamline components that are beyond the production limits of commercial suppliers. Metrology data is routinely used to guide Engineering design decisions, following the mechatronics principle.

Coupled with faster detectors, X-ray optic upgrades, new flagship beamlines, and advanced data pipelines, the new low emittance Diamond-II source will benefit a wide range of scientific communities. Smaller, brighter, X-ray beams enable sample scanning systems to progress from slow, step-based motion to rapid, freeform dynamic trajectories. Metrology feedback devices, such as interferometers or capacitive displacement sensors, are increasingly used for real-time monitoring and correction of parasitic errors of micro- and nano-positioning stages [\*]. Beamlines are often noisy environments, with mechanical, acoustic and electrical disturbances, and temperature or humidity fluctuations. To provide accurate, closed-loop feedback for nano-positioning stages, metrology instruments need to be calibrated and optimised to nullify errors caused by variations on the beamline [\**]. We demonstrate the importance of characterising a nano-positioning stage in the ultra-stable environment of the Precision Metrology Lab using a traceable, linear interferometer. Lessons learnt are applied to compensate for environmental changes in “real-world” beamline conditions to achieve sub-nm nano-positioning.

Deterministic polishing of X-ray mirror for synchrotron light and XFEL sources requires metrology instruments capable of accurately measuring optics with slope errors < 50 nrad RMS and height errors < 1 nm peak-to-valley. To improve the performance of the Diamond-VeNOM slope profiler [\*], we have developed an ultra-stable, 3-axis rotation stage [\**] to orient the mirror under test. The goniometer employs a spherical air-bearing, actuated by three piezo-walkers via flexure struts. This combination provides high stiffness, zero friction, and minimal parasitic errors. Linear interferometers provide positional feedback to the piezo actuators for fast, closed-loop control of 3D angles. Temperature controllers and forced air stabilisation minimise thermal drifts. FEA and dynamic model-ling optimised all components via mechatronic principles. The goniometer can accommodate X-ray mirrors up to 500 mm long and 10 kg in mass. It has an angular range of ± 10 mrad in 3 orthogonal directions, a minimal incremental step of < 100 nrad, and thermal drift of ~ 100 nrad over 30 minutes. Shielding of heat sources reduces air turbulence for probing autocollimators or laser beams. The system is controllable via EPICS to enable dynamical synchronisation with other motion stages and detectors

The IXS High Resolution Monochromator (HRM) on the Petra III Beamline P01 is used for the medium X-ray range from 2.5keV to 3.5keV. The core piece is a disk that carries the crystals. An encoder ring is attached to the circumference. A radial and axial runout of less than 1µm during rotation of maximum +-20° is ensured by a high-precision spindle bearing. Rotation is performed by a PiezoLEG with a 110 mm long ceramic rod, which is coupled to the disk and offers an angular resolution of 100nrad at best. The HRM has been in operation since mid-2017 with four independent superstructures - two for the inline arrangement, two for the nested arrangement. Unfortunately, the PiezoLEGs stop from time to time because cold welding occurs between the piezo legs and the ceramic rod in a high vacuum, which is probably due to the very long ceramic rods and the imperfect coupling to the structure. As the currently required angular resolution is 1700nrad +-500nrad, the idea arose to replace the PiezoLEGs with a pusher, driven by a stepper motor. Initial tests with a commercially available pusher show promising results in closed-loop operation.

We designed a new diffractometer with the willing to establish new standards for the exactitude and speed. This goal drove us to implement, as main rotation stage, an air bearing rotating up to 1000°/s with a sphere of confusion of the hundred of nanometer range. Achieving such performance requires not only cutting-edge technical development and manufacturing of the device itself, but also the proper metrology set-up to control the performance of the rotational stage. The exactitude to reach made us questioning the metrology procedure used for rotation stages. As a result, our work has aimed to establish robust procedure applicable when high precision rotation stage is involved such as in diffractometer for X-ray or neutron diffraction (powder or crystal) or the the trending nano-tomography or nano X-ray imaging. We will present our results for three different methods. We established one method using the embedded high resolution viewing device (on-axis camera) in visible light (possible daily use) that we compared with two others, one using capacitive sensors and one relying on interferometry to get the most accurate metrology.

We developed a novel medium energy resolution monochromator(MRM) for Resonant Inelastic X-ray Scattering (RIXS) experiments at the High Energy Photon Source (HEPS) featuring an integrated flexible high-precision positioning system that surpasses conventional designs. Our rotation platform delivers unprecedented performance with a travel range of hundreds of milliradians—three times greater than existing systems—while maintaining sub-microradian precision, with potential for nano-radian resolution if an additional simple configuration is developed. The breakthrough innovation is our two-axis rotation mechanism using parallel decoupled architecture that uniquely combines structural rigidity with precise motion control, solving the longstanding challenge of spatial motion decoupling while enhancing stability. Rigorous simulation and testing confirm all performance metrics exceed design targets. This technology not only meets the exacting requirements for monochromators but extends high-precision capabilities in high-vacuum environments, with our parallel decoupling principle offering transformative potential across multiple precision engineering applications.

The 40-year-old SX700 monochromators are being replaced due to missing spare parts. The new monochromator reuses the existing synchrotron optics, reducing both integration effort and system costs. A key challenge was the eccentric motion of the 650 mm, 7 kg pre-mirror. A novel UHV-precision drive combining a planetary roller screw and torque motor was developed to provide high thrust and precision up to 1 degree/s over a 27 degree range$*$. This doubles the angular range of the original SX700 and enabling fast XUV energy scans. A new stepper-driven grating revolver alternates between two gratings. Absolute angle encoders, developed as RON905 replacements, provide 0.02 arcsec precision for both mirror and grating axes$**$. A specially designed tilted UHV chamber fits the space constraints while maintaining a compact overall structure$***$. Infrared monochromatizating and optical alignment via visible light diffraction with geodetic instruments are possible. After successful drive tests, the full design is finalized, and the first Prototype is ready for production. This poster presents the final design and compares its performance to modern monochromators.

New high-resolution X-ray beamlines demand reflective optics with higher surface profile accuracy to achieve diffraction-limited focusing. This necessitates advanced metrology instruments capable of delivering repeatable measurements in the nanometer to sub-nanometer range. Slope ranges exceeding 15 mrad (0.86°) and greater pose significant challenges for mirror metrology using conventional interferometric methods especially on shorter mirrors with low radius of curvature (<20 m). To address this, we present a new Relative Angle Determinable Stitching Interferometry (RADSI) instrument featuring a parallel flexure-based mechanical design. This approach enhances vibration and thermal stability while maintaining a compact and lightweight system. Initial measurements of a cylindrical mirror with a 16 m radius of curvature and a slope range of 5 mrad demonstrate nanometer-level repeatability. Comprehensive system characterization suggests the potential for achieving sub-nanometer repeatability with further refinement to the instrument.

The ALBA Synchrotron has recently opened a Nanomotion Laboratory to support the upcoming ALBA II upgrade to a 4th-generation light source. The laboratory is dedicated to research, development, and commissioning of high-performance motion-and-positioning instrumentation, control systems, and synchronisation between components. It is operated as a clean room with particles, humidity, pressure and temperature control, built in the Experimental Hall to benefit from the main slab’s vibration isolation. This work presents the laboratory’s specialised spaces, infrastructure, and capabilities, together with commissioning data that verify the design specifications. We also highlight current collaborations within ALBA and invite external partners to explore joint projects that leverage the laboratory resources.