Mechanical Design of the MID Split-and-Delay Line at the European XFEL

A new split-and-delay line (SDL) is under development for the Materials Imaging and Dynamics (MID) end station at the European XFEL.* The device utilises Bragg reflection to provide pairs of X-ray pulses with an energy of (5 - 10) keV and a continuously tunable time delay of (-10 - 800) ps - thus allowing zero-crossing of the time delay. The mechanical concept features separate positioning stages for each optical element. Those are based on a serial combination of coarse motion axes and a fine alignment 6 DoF Cartesian parallel kinematics**. That allows to meet the contradictory demands of a fast long-range travel of up to 1000 mm and in the same time a precise alignment with a resolution in the nanometer range. Multiple laser interferometers monitor the position of the optical elements and allow an active control of their alignment. All optical elements and mechanics will be installed inside an UHV chamber, including the interferometer and about 100 stepper motors. With this paper we present the mechanical design for the SDL. It will additionally show the design of a prototype of a positioning stage which allows extensive testing of the implemented concepts and techniques

Development of a hard X-ray split-and-delay line and performance simulations for two-color pump-probe experiments at the European XFEL

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Review of Scientific Instruments 89, 063121 (2018) and may be found at https://doi.org/10.1063/1.5027071.A hard X-ray Split-and-Delay Line (SDL) under construction for the Materials Imaging and Dynamics station at the European X-Ray Free-Electron Laser (XFEL) is presented. This device aims at providing pairs of X-ray pulses with a variable time delay ranging from −10 ps to 800 ps in a photon energy range from 5 to 10 keV for photon correlation and X-ray pump-probe experiments. A custom designed mechanical motion system including active feedback control ensures that the high demands for stability and accuracy can be met and the design goals achieved. Using special radiation configurations of the European XFEL’s SASE-2 undulator (SASE: Self-Amplified Spontaneous Emission), two-color hard x-ray pump-probe schemes with varying photon energy separations have been proposed. Simulations indicate that more than 109 photons on the sample per pulse-pair and up to about 10% photon energy separation can be achieved in the hard X-ray region using the SDL.BMBF, 05K13KT4, Verbundprojekt FSP 302 - Freie-Elektronen-Laser: Nanoskopische Systeme. Teilprojekt 1: Split-and-Delay Instrument für die European XFEL Beamline Materials Imaging and DynamicsBMBF, 05K16BC1, Split-and-Delay Instrument für die European XFEL Beamline Materials Imaging and Dynamic

Flexure Joined Parallel Kinematics for Ultrapecision Movements in Vacuum

Die vorliegende Arbeit beschreibt ein neuentwickeltes räumliches Führungsgetriebe zur ultrapräzise bewegbaren Führung von Spiegeln. Der Aufbau und die Wirkungsweise sowie die Vorzüge und Grenzen dieses parallelkinematischen Koppelgetriebes werden im ersten Teil diskutiert. Die Struktur basiert auf der bewegungsbezogenen Anordnung von Stäben, die an beiden Enden neuentwickelte elastische Gelenke aufweisen. Diese Fasergelenke werden im zweiten Teil der Arbeit vorgestellt. Weiterhin wird das Antriebskonzept beschrieben, das auf einem neuentwickelten Linearantrieb beruht. Getriebestruktur, Gelenke und Antriebe verschmelzen zu einem elastischen Mechanismus im Ultra-Hoch-Vakuum (UHV), der die Präzision herkömmlicher Gestaltungen um mehrere Größenordnungen übertrifft. Im dritten Teil dieser Dissertation werden fünf realisierte Ausführungen beschrieben. Über die Anwendung für optische Geräte der Synchrotronstahlquellen hinaus haben die in dieser Arbeit besprochenen Konzepte ein Anwendungspotential in anderen Bereichen der Technik. Die mechanischen Komponenten der Medizintechnik sowie im Werkzeugmaschinen-, Flugzeug- und Fahrzeugbau können genauer, einfacher und leichter werden, wenn die tragenden Strukturen so gestaltet werden, daß sie die Bewegungen unter Ausnutzung der Materialelastizität führen

A soft x ray fluorescence spectrometer at BESSY II

A new spectrometer for resonant inelastic x ray scattering experiments has been designed and is currently built at the synchrotron light facility BESSY II. The spectrometer with a total length of 3 m covers the photon energy range from 50 eV to 1000 eV with emphasis on the lower photon energy range. It is designed as plane grating spectrometer with two paraboloidal mirrors for collimation and focusing and a plane grating in between. Two rotational degrees of freedom allow for a variation of the incidence and deflection angles at the grating. The geometrical acceptance of the spectrometer approaches a solid angle of 35 mrad 40 mrad2 at low photon energies with a resolution better than 10 meV at 100 eV. A rotatable delay line detector is used to detect the fluorescence light in the line focu

Proposal for a Universal Test Mirror for Characterization of Slope Measuring Instruments

The development of third generation light sources like the Advanced Light Source (ALS) or BESSY II brought to a focus the need for high performance synchrotron optics with unprecedented tolerances for slope error and micro roughness. Proposed beam lines at Free Electron Lasers (FEL) require optical elements up to a length of one meter, characterized by a residual slope error in the range of 0.1murad (rms), and rms values of 0.1 nm for micro roughness. These optical elements must be inspected by highly accurate measuring instruments, providing a measurement uncertainty lower than the specified accuracy of the surface under test. It is essential that metrology devices in use at synchrotron laboratories be precisely characterized and calibrated to achieve this target. In this paper we discuss a proposal for a Universal Test Mirror (UTM) as a realization of a high performance calibration instrument. The instrument would provide an ideal calibration surface to replicate a redundant surface under test of redundant figure. The application of a sophisticated calibration instrument will allow the elimination of the majority of the systematic error from the error budget of an individual measurement of a particular optical element. We present the limitations of existing methods, initial UTM design considerations, possible calibration algorithms, and an estimation of the expected accuracy

Sehen, Fühlen, Erfahren: Rechtsmedizin mit mARBLE® erleben

Noll C, von Jan U, Schaft T, Matthies HK, Albrecht U-V. Sehen, Fühlen, Erfahren: Rechtsmedizin mit mARBLE® erleben. In: Reiterer H, Deussen O, eds. Mensch & Computer 2012 : interaktiv informiert - allgegenwärtig und allumfassend!? : 12. Fachübergreifende Konferenz für Interaktive und Kooperative Medien. München: Oldenbourg; 2012: 241-246

Proposal for a Universal Test Mirror for Characterization of Slope Measuring Instruments

The development of third generation light sources like the Advanced Light Source (ALS) or BESSY II brought to a focus the need for high performance synchrotron optics with unprecedented tolerances for slope error and micro roughness. Proposed beam lines at Free Electron Lasers (FEL) require optical elements up to a length of one meter, characterized by a residual slope error in the range of 0.1murad (rms), and rms values of 0.1 nm for micro roughness. These optical elements must be inspected by highly accurate measuring instruments, providing a measurement uncertainty lower than the specified accuracy of the surface under test. It is essential that metrology devices in use at synchrotron laboratories be precisely characterized and calibrated to achieve this target. In this paper we discuss a proposal for a Universal Test Mirror (UTM) as a realization of a high performance calibration instrument. The instrument would provide an ideal calibration surface to replicate a redundant surface under test of redundant figure. The application of a sophisticated calibration instrument will allow the elimination of the majority of the systematic error from the error budget of an individual measurement of a particular optical element. We present the limitations of existing methods, initial UTM design considerations, possible calibration algorithms, and an estimation of the expected accuracy

High precision tilt stage as a key element to a universal test mirror for characterization and calibration of slope measuring instruments.

The ultimate performance of surface slope metrology instrumentation, such as long trace profilers and auto-collimator based deflectometers, is limited by systematic errors that are increased when the entire angular range is used for metrology of significantly curved optics. At the ALS X-Ray Optics Laboratory, in collaboration with the HZB/BESSY-II and PTB (Germany) metrology teams, we are working on a calibration method for deflectometers, based on a concept of a universal test mirror (UTM) [V. V. Yashchuk et al., Proc. SPIE 6704, 67040A (2007)]. Potentially, the UTM method provides high performance calibration and accounts for peculiarities of the optics under test (e.g., slope distribution) and the experimental arrangement (e.g., the distance between the sensor and the optic under test). At the same time, the UTM calibration method is inherently universal, applicable to a variety of optics and experimental arrangements. In this work, we present the results of tests with a key component of the UTM system, a custom high precision tilt stage, which has been recently developed in collaboration with Physik Instrumente, GmbH. The tests have demonstrated high performance of the stage and its capability (after additional calibration) to provide angular calibration of surface slope measuring profilers over the entire instrumental dynamic range with absolute accuracy better than 30 nrad. The details of the stage design and tests are presented. We also discuss the foundation of the UTM method and calibration algorithm, as well as the possible design of a full scale UTM system