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The Berlin Joint Lab for Electrochemical Interfaces BElChem is located at the BESSY II synchrotron in Berlin, Germany, and co run by the Fritz Haber Institut, the Max Planck Institut of Chemical Energy Conversion and the Helmholtz Zentrum Berlin. BElChem focuses on providing a molecular level description of photo electrochemical interfaces that are of high relevance for solar fuel production and renewable energy storage. The CO2 reduction reaction CO2RR and the oxygen evolution reaction OER are of particular current interest. In BElChem, near ambient pressure X ray photoelectron spectroscopy NAP XPS and near ambient pressure hard X ray photoelectron spectroscopy NAP HAXPES will be used for the in situ and operando interrogation of the electronic structure and chemical composition of catalytically active solid gas and solid liquid interfaces. BElChem will also enable heterogeneous catalytic reactions, such as oxidation and hydrogenation reactions, to be investigated

SESAME and a consortium of five Helmholtz Centers are designing and installing a state-of-the-art soft X-Ray undulator beamline at the SESAME light source in Amman, Jordan. Funding is provided by the Helmholtz Association over a four year project cycle that started in January 2019. This is an interim report covering the first 36 months of the project where the construction and installation has been almost completed and commissioning and characterization of the beamline is about to start. Additionally, seminars, workshops, and a training program are part of the project aimed at establishing a broad user community.

We present the experimental end-station TRIXS dedicated to time-resolved soft x-ray resonant inelastic x-ray scattering (RIXS) experiments on solid samples at the free-electron laser FLASH. Using monochromatized ultrashort femtosecond XUV/soft x-ray photon pulses in combination with a synchronized optical laser in a pump-probe scheme, the TRIXS setup allows measuring sub-picosecond time-resolved high-resolution RIXS spectra in the energy range from 35 eV to 210 eV, thus spanning the M-edge (M$_1$ and M$_{2,3}$) absorption resonances of 3d transition metals and N$_{4,5}$-edges of rare earth elements. A Kirkpatrick–Baez refocusing mirror system at the first branch of the plane grating monochromator beamline (PG1) provides a focus of (6 × 6) $μm^2$ (FWHM) at the sample. The RIXS spectrometer reaches an energy resolution of 35–160 meV over the entire spectral range. The optical laser system based on a chirped pulse optical parametric amplifier provides approximately 100 fs (FWHM) long photon pulses at the fundamental wavelength of 800 nm and a fluence of 120 mJ/cm$^2$ at a sample for optical pump-XUV probe measurements. Furthermore, optical frequency conversion enables experiments at 400 nm or 267 nm with a fluence of 80 and 30 mJ/cm$^2$, respectively. Some of the first (pump-probe) RIXS spectra measured with this setup are shown. The measured time resolution for time-resolved RIXS measurements has been characterized as 287 fs (FWHM) for the used energy resolution.

The knowledge of material properties is an essential step to design particle accelerators and High Energy Colliders. During operation of these machines, the walls of the vacuum chambers are subjected to bombardment of photons and electrons. The detrimental interactions may be followed by issues related to vacuum and beam instability. Hence, it becomes crucial to obtain experimental data about these interaction in conditions as close as possible to the operative ones. Among others properties, Reflectivity (both specular and total component) and photoyield are of particular interest. These data will be used in numerical simulations to design vacuum systems. In an experimental campaign, carried out at the OPTICS beamline of BESSYII, we investigated the Reflectivity and the Photon Yield of technical materials of interest for the High Luminosity LHC upgrade and Future Circular Collider-hh design., CERN Yellow Reports: Conference Proceedings, Vol. 7 (2020): ECLOUD’18 : Proceedings of the Joint INFN-CERN-ARIES Workshop on Electron-Cloud Effects, 3–7 June 2018, La Biodola, Isola d’Elba, Italy

The non monochromatic beamline BL1 at the FLASH free electron laser facility at DESY was upgraded with new transport and focusing optics, and a new permanent end station, CAMP, was installed. This multi purpose instrument is optimized for electron and ion spectroscopy, imaging and pump probe experiments at free electron lasers. It can be equipped with various electronand ion spectrometers, along with large area single photon counting pnCCD X ray detectors, thus enabling a wide range of experiments from atomic, molecular, and cluster physics to material and energy science, chemistry and biology. Here, an overview of the layout, the beam transport and focusing capabilities, and the experimental possibilities of this new end station are presented, as well as results from its commissioning

A high brightness photoelectron injector must be developed as a part of the BERLinPro ERL program. The injector is designed to produce an electron beam with 100mA average current and a normalized emittance of 1mm mrad. The project is realised in stages. First experience is gained with a fully superconducting RF gun with a Pb cathode, work ongoing, followed by a normal conducting CsK2Sb cathode capable of generating high current beams. In the first stage we have measured the fundamental beam parameters bunch charge, beam energy and energy spread with a special focus on the measurement of the transverse beam profiles. We also discuss our plans for the beam characterization at high currents.

To take benefit from the improved brilliance of the laser‐like source, proposed beamlines at Free Electron Lasers (FEL) require optical elements of excellent precision, characterised by slope errors beyond the state of the art limit of 0.5μrad rms for plane and spherical shape. Part of the monochromator beamline for self‐seeding at the vacuum‐ultraviolet Free Electron Laser (FLASH) at DESY is a triple Variable Line Spacing (VLS) grating of spherical shape. The three grating structures on a common substrate will cover the wavelength range from 6.4 to 60nm The challenging specifications of these grating structures are characterised by a slope error of less than 0.25μrad rms and very stringent parameters for the VLS‐polynomial. These grating structures have been measured by use of the Nano Optic Measuring Machine (NOM) at BESSY. Based on the principle of deflectometry the BESSY‐NOM represents the latest generation of slope measuring metrology instruments. The NOM enables the inspection of optical components with a measurement uncertainty in the range of 0.05μrad rms. This is a five to tenfold improvement compared to state of the art metrology tools of today. Here it is demonstrated how these outstanding metrology capabilities have been applied for a sound characterisation of a challenging precision optical component with error limits five times below the specifications. In the shown example the grating’s figure accuracy has been characterised by linescans and surface mapping measurements of the optical active sections. In additional measurements under Littrow condition the higher order diffraction signals of the laser pencil beam have been traced to measure the groove density variation of the different grating‐structures with a lateral resolution of 1mm. In contrast to the sparse and point like measurements of the manufacturer, these high resolution measurements yield a “slope deviation equivalent” resulting from imperfections in the line density variation.