Search

In this paper, a new effective wavelength calibration technique has been investigated and calculated for the calibration of different monochromator systems. Different calibration lamps have been tested effectively with respect to similar studies. Extended wavelength accuracy calibration has been made for the spectrophotometer systems, which have different grating with different spectral range. For each grating, different calibration lamps was used. Wavelength calibration over extended range has been possible by using orders of gratings. Integrating sphere usage has been a simpler way compared to conventional optical setups and a unique approach on uniformly transferring radiation of the calibration lamps to monochromator systems. This experimental setup, allows the correct wavelength of the radiation to reach entrance slit without causing optical aberrations. Many parameters have been analyzed in uncertainty measurements both standard uncertainty calculation method, which are based on the “Guide to the Expression of Uncertainty in Measurement” (GUM) and other method is the Monte Carlo (MC) described in e GUM Supplement-1. Hence, the precision is improved in results. Extended uncertainty results are in between 0.02 nm and 0.3 nm with 95% confidence level (k=2) for both monochromator systems. [ABSTRACT FROM AUTHOR]

The EXAFS BL-09 beamline of Indus-2, RRCAT have been in growing demand owing to their outstanding performance for x-ray absorption (XAFS) data collection in transmission mode and fluorescence mode. To take full advantage of the state-of-the-art of this beamline, a significant effort has been devoted for designing of 5-Circle diffractometer to perform depth-selective XAFS study and fast, intuitive beamline controls through EPICS and SPEC diffractometer-control program to perform x-ray reflectivity (XRR) and XAFS measurements. In the present work, we mainly focus on the communication of Si(111) double crystal monochromator and 3 ionization chambers whose output is connected with 4 channel TetrAMM picoammeter through EPICS for XAFS measurement and using Mythen Detector (1D) for X-ray reflectivity (XRR) measurement at various energies. [ABSTRACT FROM AUTHOR]

One of the beamlines at Taiwan Photon Source (TPS), numbered as TPS 44A, is for Extended X-ray Absorption Fine Structure experiments. The main components include a collimation mirror, a focusing mirror, and a quick-scan double crystal monochromator. There are also various diagnosis and monitoring equipment. It uses four-blade slits to constrain the beam size and block unwanted part. Besides, current amplifiers are attached to the slits. At the locations in front or at rear of some mirrors which can change the direction of the x-ray beam, there are fluorescent screens and cameras to observe positions and strength of the beam. Most of them need electronic motors or high-pressure air to be movable and controllable from a remote control system. If there exists one integrated control system for all equipment, it will be easier for the scientists to operate the beamline, adjust the conditions of various parameters, do the commissioning, and concentrate on the experiments. [ABSTRACT FROM AUTHOR]

We have constructed a new soft X-ray beamline, namely the Taiwan Photon Source (TPS) 45A NSRRC-MPI beamline, to facilitate submicron angle-resolved photoemission spectroscopy (ARPES) experiments with ultra-high energy resolution. The beamline uses an elliptically polarized undulator with 46 mm magnet period (EPU46) that provides photon energies from 280 to 1500 eV with horizontal and vertical linear polarization, as well as left and right circular polarization. The vertical focusing mirror (VFM) and the active grating monochromator (AGM) utilize the novel 25-actuator optical surface bender developed for ultra-high resolution soft X-ray spectroscopies. With the surface slope error being reduced down to 0.03 μrad root-mean-square (rms) by the bender as verified by the long trace profiler (LTP) measurements, the ray-tracing simulation shows that an energy resolution of 5 meV can be achieved at 750 eV photon energy and the beam spot size can each 0.5 μm × 0.4 μm at the sample position. By adjusting only the 6 actuators to control the surface major profile, our preliminary results show that the VFM is able to focus 70% of the photon flux from EPU46 through an entrance slit set at 1.9 μm opening. As deduced from the measured ARPES data at the Fermi-level of Au, the energy resolving power of the monochromator was found to reach 34,000 full-width-half-maximum (FWHM) at 850 eV photon energy. By using the in-vacuum LTP measurement system currently under development and all 25 actuators of the surface bender, we anticipate to further reduce greatly the intrinsic and thermal-induced slope errors of the VFM and AGM. It is feasible that the overall ARPES energy resolving power can reach the 140,000 target in the soft X-ray spectral region. [ABSTRACT FROM AUTHOR]

The X-ray beamline TPS 02A is making use of the bending magnet source at the Taiwan Photon Source (TPS), which is dedicated to performing full-field hard X-ray projection imaging at micron size spatial resolutions in the photon energy range of 5 - 25 keV. It provides the photon flux > 4.2 × 1011 photons·s−1 with energy resolution < 1.72 × 10-3, the beam size is 35.5 (H) × 8.5 (V) mm² and beam divergence is 1.2 (H) × 0.3 (V) mrad² at the sample position. The microscope is capable of examining anatomical information and internal distribution of microstructures by tuning the energy of the photon source to the absorption edge of the samples through the use of a monochromator. Phase contrast tomography is also available for imaging the fine details of in the morphology of the sample. [ABSTRACT FROM AUTHOR]

In order to ensure rapid and successful operation of the high performance beamline instruments and optics, a test beamline (09B) has been built at Shanghai Synchrotron Radiation Facility (SSRF) for the at-wavelength measurements. The bending magnet is employed as the light source, and the acceptance angle is2.5×0.3mrad². The beamline optical elements: 1D compound refractive lens, water cooling double crystal monochromator, toroidal mirror and other optical components could be switched in the vacuum for different operational modes. A KB mirror system is employed to micron focus at the experimental station, and the beamline provides 100mm spot size in horizontal direction. The beamline photon energy range is 4-50keV, energy resolution is 5x10−4@10keV and photon flux is 3x1011phs/s@300mA. Variety instruments and detectors have been provided for the diffraction, spectroscopy, imaging and other at-wavelength measurement. Details of the beamline optical design and energy resolution measuring performance of the high energy double Laue crystal monochromator and water cooling double crystal monochromator are also presented in this paper. [ABSTRACT FROM AUTHOR]

A soft X-ray nanoscopy beamline (SXNB) at the Taiwan Photon Source (TPS) is designed to deliver photons of 90 – 2,500 eV from an elliptically polarized undulator to two state-of-the-art microscopy stations hosting the scanning transmission X-ray microscope (STXM) and the photoelectron related imaging and nanoscope (PRINS), respectively. The heart of SXNB is an active grating monochromator (AGM) that optimizes the flux and energy resolution at the same time while maintaining a stable focal spot on the sample. This article describes the design concept, optical layout, and simulation results of SXNB. [ABSTRACT FROM AUTHOR]

A biosafety level-2 beamline for macromolecular crystallography is constructing at SSRF, which is one of the beamlines in phase-II beamline project approved at 2016 by the central government of China. This beamline will provide the capability of conducting the experiment on determination of the virus-related protein structure from crystals. To fulfill this aim, the end station is emphasized on the biosafety design which must meet the Chinese laws and regulations. For the limited source of insertion section in the storage ring, the beamline will be one of the canted beamline, sharing the insertion with the ultra-small angle X-ray scattering beamline. The photon source will be a 1.6 m long, in-vacuum undulator with period of 22 mm. The optics will consist of a deflection flat mirror to increase the distance of two canted beamline, a cryogenically cooled Si(111) double-crystal monochromator and focusing mirrors. The focus scheme is realized with two-stage focus scheme in horizontal and one stage focus in vertical direction. At the sample position the focused beam is 20 micron in horizontal and 10 micron in vertical. The beam size could be changed by inserting the compound refractive lens. The beamline will deliver a high flux beam in the 7-18 keV energy range, with the energy resolution of ΔE/E ~2×10−4. In addition to the main beamline, the endstation will be negative pressure control and be functional divided to meet the biosafety regulations. This report shows the current status of the beamline design. [ABSTRACT FROM AUTHOR]

The XMaS bending magnet beamline at the ESRF has been in regular user operation since the autumn of 1998 and has employed a very simple optical system consisting of a Si <111> monochromator and a toroidal mirror. The ESRF extremely brilliant source (EBS) upgrade program presents the bending magnet beamlines with a series of challenges and exciting new opportunities to extend the range of science performed, with emphasis on in-operando and in-situ studies. Geometrically, the new EBS lattice will move the source for bending magnet beamlines some 3 meters upstream and XMaS will use a newly designed 0.86 Tesla short bend, instead of the present 0.4 Tesla bending magnet. The higher field of the new source increases the available flux at high energies (>25 keV) by an order of magnitude and will result in a smaller brighter beam. To exploit the extended energy range, a dual toroidal mirror system, coated with chromium and platinum, will provide the focusing optics and enable continuous operations from 2.035 keV to 33 keV which will be coupled to a fast scanning LN2 cooled, constant offset monochromator. We report here on the opportunities presented by the new machine lattice and the solutions chosen to deliver a state of the art beamline that utilizes a very wide range of x-ray techniques including scattering and spectroscopy from a broad spectrum of materials characterization. [ABSTRACT FROM AUTHOR]

In Phase-II project at Shanghai Synchrotron Radiation Facility (SSRF), a sub-micron protein crystallography beamline is designed to achieve the focused beam size from 0.5 μm to 20μm. The high harmonics in the spectrum of a cryogenic permanent magnet undulator (CPMU) is adopted to provide X-rays in 5~25keV. A LN2 cooled double crystal monochromator (DCM) for high energy resolution mode and a double multilayer monochromator (DMM) for high photon flux mode will be used to monochromatize the beam while two-stage focusing optics will be selected to focus the beam. A pair of pre-focusing KB mirrors will generate a secondary source while a second pair of KB mirrors will image the secondary source to a half micron size beam at the sample position. The experimental end station will provide highresolution native data collection with experimental phasing method (SAD/MAD), in-situ 96-well plate data collection, raster strategy for tiny crystals, and serial crystallography method. [ABSTRACT FROM AUTHOR]

The CARNAÚBA beamline is the tender-to-hard X-ray nanoprobe under construction for the new source Sirius at the Brazilian Synchrotron Light Laboratory (LNLS). The all achromatic optics relies on KB mirrors and a horizontal secondary source aperture (SSA) to reach beam size down to ~30x30 nm² at the sample position. To handle the power on the optical elements the choice has been to build instruments based on cryogenically cooled Si crystals. These optical elements – X-ray diagnostic, primary mirrors, secondary source aperture and monochromator – and expected performance are described here. [ABSTRACT FROM AUTHOR]

The Paul Scherrer Institut is currently constructing Athos, its second Free Electron Laser with a photon energy range from 250 eV to 1900 eV and pulse energies up to 8 mJ. A single soft X-ray beamline is attached to the undulator section and distributes the radiation into three branches. The beamline design is based on a variable line space spherical grating monochromator with a grating chamber and two retractable distribution mirrors. An achromatic focusing with individual KB-mirror systems downstream of the exit slits focus the beam to the endstations. The stations can operate alternatively without interfering with each other. [ABSTRACT FROM AUTHOR]

A plane-grating monochromator for the extreme-ultraviolet region that uses a plane grating operated at variable included angle and illuminated in converging light has been realized. The configuration consists of three optical elements: the focusing mirror, the plane grating and the plane mirror. In the proposed design, the spectral focusing is kept on the exit slit plane by changing the grating included angle through the use of an additional plane mirror after the grating. The coma aberration given by the grating is compensated by an opposite coma introduced by the focusing mirror, that is used in a very asymmetrical configuration. The feasibility of the configuration has been demonstrated on a monochromator for the 10-80 eV region, with sub-10-meV output bandwidth. The correction of defocusing and coma at the proper included angle has been clearly demonstrated. The monochromator efficiency has been measured to be in the 0.08-0.18 range. A plane-grating monochromator for the extreme-ultraviolet region that uses a plane grating operated at variable included angle and illuminated in converging light has been realized. The configuration consists of three optical elements: the focusing mirror, the plane grating and the plane mirror. In the proposed design, the spectral focusing is kept on the exit slit plane by changing the grating included angle through the use of an additional plane mirror after the grating. The coma aberration given by the grating is compensated by an opposite coma introduced by the focusing mirror, that is used in a very asymmetrical configuration. The feasibility of the configuration has been demonstrated on a monochromator for the 10-80 eV region, with sub-10-meV output bandwidth. The correction of defocusing and coma at the proper included angle has been clearly demonstrated. The monochromator efficiency has been measured to be in the 0.08-0.18 range. [ABSTRACT FROM AUTHOR]

The TPS 13A biological small-angle X-ray scattering (BioSAXS) beamline under construction is equipped with 4-m IU24 undulator for X-rays in the energy range of E = 4-23 keV (covering the K-edge absorptions from Ca to Ru). The beamline aims for cutting-edge researches in biomacromolecular structures and kinetics, in solid and solution, covering a wide length scale from atomic to micrometer scale and time resolution down to μs. To achieve the goals, the beamline integrates double-multilayer and double-crystal monochromators (DMM/DCM) to have an option of high flux of 4 × 1014 photons/s or a high energy resolution of ΔE/E = 1.5×10−4. The DCM together with a horizontal four-bounce crystal collimator (4BCC) will be implanted for low beam divergence to perform 2D ultra-SAXS (USAXS). To keep a common X-ray beam path of the operation modes, DMM and DCM are integrated into one rotating cradle in a same chamber for a common beam exit. Microbeam with reasonable beam divergence for SAXS/WAXS structural mapping will be realized with a virtual source defined by a set of high precision/stability slits and another set of K-B mirrors for a focus at the sample position with a demagnification close to 1.3:1. Two beam position monitors, with intensity and position feedbacks respectively to the virtual source slits and the 4BCC and a vertical deflection mirror, are used mainly to stabilize microbeam intensity and position within 1 μm in the vertical and horizontal directions. This TPS 13A BioSAXS beamline will be commissioning at the end of 2019. [ABSTRACT FROM AUTHOR]

SPring-8 standard monochromators with liquid nitrogen-cooled silicon crystals are being improved for stable use in future upgraded SPring-8. Our target amount of the vibration is 50 nrad, which is required for the stable supply of intense nanometerfocused x-rays in a typical beamline arrangement. Cryogenic cooling generates vibrations because of two factors: turbulent flow and coolant boiling. Since the latter is caused by low flow rate, further increase in flow rate is required together with a decrease in vibration. For reduction of fluid resistance, a cooling system was modified with large-bore transfer pipes, and the coolant path in the monochromator was branched for both crystals. For reduced vibration, we improved low-vibration flexible tubes, simplified the stage configuration in the monochromator, and increased the rigidity of tilt stages. As a result, no boiling was observed for heat load of more than 400 W. The vibrations were suppressed to approximately 110 nrad for most monochromators. The best stability of 55 nrad was achieved for a monochromator. [ABSTRACT FROM AUTHOR]

We report on performance of chemical vapor deposited (CVD) single crystal diamond plates as side bounce monochro-mators for high photon energies (≳ 20 keV) in the Laue geometry. Several crystals were tested in-operando high-heat-load conditions at A1 undulator station of Cornell High Energy Synchrotron Source. Up to 10× enhancement in the reflected x-ray flux was observed compared to that delivered by IIa diamond plates grown by high-pressure high-temperature method. Wavefront distortions were measured using analyzer-based x-ray diffraction imaging. Focusing of a portion of the reflected beam was demonstrated using Pt-coated mono capillary optics at a photon energy of 46 keV. [ABSTRACT FROM AUTHOR]

X-ray mirrors with sagittal curvature are often used at X-ray beamlines to focus or collimate the beam horizontally. However, if placed in front of a monochromator, the vertical beam divergence introduced by such mirrors can significantly decrease energy resolution and make the beamline more sensitive to misalignment. Such is the case of BioXAS-Side beamline at the Canadian Light Source Inc. To find a cost effective way to minimize the negative effects of a toroidal first mirror while preserving flu x, we used the ray tracing package XRT to simulate the beamline, understand the cause of the observed problems, and investigate ways to improve performance. We confirmed that the optimal solution would be to limit the horizontal acceptance of the toroidal mirror, as commonly done, because the sagittal curvature of the mirror contributes to the vertical deflection of the light rays proportionally to their transversal coordinate. However, that was not an option in our case given the high cost of white-beam slits and space limitations specific to this project. Instead we used a v-shaped slit limiting the beam horizontally right after the monochromator, where rays with very different energies are still not merged together. The v-slit was cheaper to manufacture and install than a white beam slit in front of the mirror, while it improved energy resolution and decreased its dependence on beamline alignment equally well. The procedure we detail here can be generalized and used to design or improve similar systems, especially when mirrors with sagittal curvature are involved. [ABSTRACT FROM AUTHOR]

The construction of a precise temperature-controlling system for the X-ray Nanoprobe (XNP) beamline at Taiwan Photon Source (TPS) was completed and commissioned. This system includes the compact air handling units (AHUs), extruded-aluminum frames covered with double-layer plastic curtains and taken as the local temperaturecontrolled areas, fabric porous pipes, and thermally insulated pipes for air transporting. The compact AHU was developed by the members of Utility and Civil Group in National Synchrotron Radiation Research Center (NSRRC) and verified to supply air with a temperature variation within ±0.02 ℃ during 24 hours. However, the slight thermal exchange between inner and outer regions of the transporting pipes influences the temperature of supplied air. The temperature variation at air inlets of the local temperature-controlled areas was also verified within ±0.03 ℃. The precise temperature-controlling system minimizes the fluctuation of ambient temperature for the critical components, such as the monochromator, mirror system, slits and sample, therefore it enhances the thermal stability of mechanism for these components. The overall layout of hardware and testing results of the precise temperature-controlling system are described in this paper. [ABSTRACT FROM AUTHOR]

Multilayer (ML) based x-ray optics have gained considerable interest at 3rd generation synchrotron light sources. Over the last 20 years, more than 200 devices have been fabricated at the ESRF ML Laboratory and deployed on ESRF beamlines, mainly in two configurations: as Kirkpatrick-Baez (KB) focusing devices and as double-bounce high-flux monochromators. The KB mirrors are either bent or polished to their elliptical figure. The ML coatings require steep meridional thickness gradients to account for the variable angle of reflection along the beam footprint. The increased incident angles as compared to total reflection mirrors provide larger numerical apertures and therefore smaller diffraction limited focal spots. At present, ESRF KB optics reach spot sizes down to about 12 nm and are being operated up to photon energies of 65 keV. Double ML monochromators (DMM) are an interesting alternative to double crystal monochromators (DCM) whenever high flux rather than high spectral resolution is required. On many new ESRF beamlines, monochromators with bandwidths between 0.1% and 0.5% are part of the optics layout. The production of efficient DMMs with such narrow bandwidths is challenging since it implies a large number of bi-layers and low d-spacings. Possible thickness variations in depth and along the beam footprint must remain within these tolerances in order not to spoil their performance. Recently installed DMMs achieve a spectral resolution better than 0.4% and a total transmission above 50%. This paper will recall some fundamental design aspects for ML x-ray optics and show examples of applications on ESRF beamlines. It will address present limitations and discuss possible approaches to improve the ML performance. [ABSTRACT FROM AUTHOR]

A new undulator beamline (P22) for hard X-ray photoelectron spectroscopy (HAXPES) was built at PETRA III (DESY, Hamburg) to meet the increasing demand for HAXPES-based techniques. It provides four special instruments for high-resolution studies of the electronic and chemical structure of functional nano-materials and catalytic interfaces, with a focus on measurements under operando and/or ambient conditions: (i) a versatile solid-state spectroscopy setup with optional wide-angle lens and in-situ electrical characterization, (ii) a HAXPEEM instrument for sub-μm spectro-microscopy applications, (iii) an ambient pressure system (> 1 bar) for operando studies of catalytic reactions and (iv) a time-of-flight spectrometer as a full-field k-microscope for measurements of the 4D spectral function ρ(EB,k). The X-ray optics were designed to deliver high brightness photon flux within the HAXPES energy range 2.4 – 15 keV. An LN2-cooled double-crystal monochromator with interchangeable pairs of Si(111) and (311) crystals is optionally combined with a double channel-cut post-monochromator to generate X-rays with variable energy bandpass adapted to the needs of the experiment. Additionally, the beam polarization can be varied using a diamond phase plate integrated into the beamline. Adaptive beam focusing is realized by Be compound refractive lenses and/or horizontally deflecting mirrors down to a spot size of ~20x17 μm² with a flux of up to 1.1x1013 ph/s (for Si(111) at 6 keV). [ABSTRACT FROM AUTHOR]

The layout and the characteristics of the Quick scanning EXAFS (QEXAFS, ref. [1]) setup at beamline P64 at the storage ring PETRA III, DESY, Germany are described. The quickly oscillating cryo-cooled monochromator allows measurements from 4.5 keV to 44 keV with frequencies up to 100 Hz. The effect of tapering of the undulator on spectra as well as the different detection schemes with transmission, reflectivity and fluorescence are discussed. The data acquisition is explained in detail. Reference spectra at different frequencies and examples of time resolved user experiments are shown. The influence of noise and filtering on the spectra is analysed. [ABSTRACT FROM AUTHOR]

The SIRIUS beamline at Synchrotron Soleil, utilizing the energy range between 1.4-13 keV, provides tools to do structural study of condensed matter. The beamline, here mounted on an HU36 undulator source with two monochromators, is suitable of providing x-ray characterization techniques such as: grazing incidence x-ray diffraction (GIXRD), small angle scattering (GISAXS) at fixed energy, and anomalous x-ray diffraction (AXD) and spectroscopies (XAFS, DAFS) in energy scans. Recently, the SIRIUS beamline had their Double Crystal Monochromator control system (black-box and ready-to-use) replaced and upgraded. This was a decision made to facilitate easier system maintenance and add new functionalities such as continuous scanning with the possibility of low-level kinematic conversions (for energy scans); all while adhering to standardized control solutions supported by the Electronics and Control- group in Synchrotron SOLEIL. The flexibility and modularity of the new system, here based on the Delta Tau PMAC platform allowed for interfacing with non-standard black-boxed motorized systems. We will here present; the architecture with its modular MACRO field bus communication protocol and how it can be extended to implement control over exotic motorized systems in a standard way, as well as results from step scans and continuous energy scans using low-level kinematic conversions. [ABSTRACT FROM AUTHOR]

An undulator usually emits radiation at the energy of the fundamental wavelength and the higher harmonics at the same time. Likewise, monochromators with gratings or low-indexed crystals also transmit these higher harmonics with substantial efficiency. Most experiments, however, require a clean monochromatic spectrum and use mirrors or a detuning of the monochromator to suppress the higher harmonics in the spectrum. A quasi-periodic undulator is a well-established device which shifts the position of the higher harmonics to non-integer multiples of the fundamental and helps to improve the signal-to-background ratio in the measurement significantly. We have implemented a new alternative concept for suppression of higher harmonics which can be adapted on the fly during operation of the undulator. It is based on creating a distinct phase step in the center of the magnet structure which leads to a tailored distortion of the emitted spectrum. For that purpose, a permanent magnet phase shifter is embedded into the magnet structure of a planar hybrid undulator. We discuss the principle and technical implementation of this scheme, and present first experimental results. [ABSTRACT FROM AUTHOR]

Hard X-ray Free Electron Lasers (XFEL) generate intense coherent X-ray beams by passing electrons through very long periodic magnet structures, which extend over hundreds of meters. The SASE1 and SASE2 undulator systems of the European XFEL consist of 35 segments with variable gap planar undulators which are initially tuned to precise onaxis magnetic field strengths in a magnetic measurement lab to keep a quality parameter, the K-value variation from segment to segment below the pierce parameter. After tunnel installation only photon based methods can determine the K-values of undulator segments with a similar accuracy. The synchrotron radiation from single or a few segments can be spectrally filtered by a dedicated crystal monochromator (K-monochromator) and recorded with either a point detector such as a photo diode or with an imager that provides 2D information, tuned for high sensitivity to detect low photon densities from distant single undulator segments. This instrumentation is applied for electron orbit analysis and optimization, and adjustment of individual undulators in terms of their central magnetic axis with respect to the electron beam. Single undulator segments were analyzed by scanning the monochromator crystal angle and detecting the steepest slope of a photo diode signal. Alternatively in the "electron-kick” method, an imager recorded the two radiation cones of electrons passing through one undulator segment, being kicked laterally and radiating a second time in the next downstream undulator. [ABSTRACT FROM AUTHOR]

The BL02B beamline at the Shanghai Synchrotron Radiation Facility (SSRF) has a high energy resolution and high photon flux. It is now operational for ambient pressure photoelectron spectroscopy (APPES) and photon-in/photon-out spectroscopy (PIPOS) experimental use. The monochromator (MONO) has three varied line spacing gratings covering an energy range from 40 to 2000 eV. Argon core-shell excitation spectra shows an energy resolving power of greater than 104 at 244 eV. The measured photon flux is 2.3×1011 photons/sec/0.1%BW at 244 eV, 3.5 GeV, and 300 mA at the sample. [ABSTRACT FROM AUTHOR]