Diffraction Beamline Research Articles

A micro-beamstop with transmission detection by fluorescence for scanning-beam synchrotron scattering beamlines

Quantitative X-ray diffraction approaches require careful correction for sample transmission. Though this is a routine task at state-of-the-art small-angle X-ray scattering (SAXS), wide-angle X-ray scattering (WAXS) or diffraction beamlines at synchrotron facilities, the transmission signal cannot be recorded concurrently with SAXS/WAXS when using the small, sub-millimetre beamstops at many X-ray nanoprobes during SAXS/WAXS experiments due to the divergence-limited size of the beamstop and the generally tight geometry. This is detrimental to the data quality and often the only solution is to re-scan the sample with a PIN photodiode as a detector to obtain transmission values. In this manuscript, we present a simple yet effective solution to this problem in the form of a small beamstop with an inlaid metal target for optimal fluorescence yield. This fluorescence can be detected with a high-sensitivity avalanche photodiode and provides a linear counter to determine the sample transmission.

Crystal structure of perfluorononanoic acid, C9HF17O2

The crystal structure of perfluorononanoic acid (PFNA) was solved via parallel tempering using synchrotron powder diffraction data obtained from the Brockhouse X-ray Diffraction and Scattering (BXDS) Wiggler Lower Energy (WLE) beamline at the Canadian Light Source. PFNA crystallizes in monoclinic space group P21/c (#14) with lattice parameters a = 26.172(1) Å, b = 5.6345(2) Å, c = 10.9501(4) Å, and β = 98.752(2)°. The crystal structure is composed of dimers, with pairs of PFNA molecules connected by hydrogen bonds via the carboxylic acid functional groups. The Rietveld-refined structure was compared to a density functional theory-optimized structure, and the root-mean-square Cartesian difference was larger than normally observed for correct powder structures. The powder data likely exhibited evidence of disorder which was not successfully modeled.

Multidimensional Rietveld refinement of high-pressure neutron diffraction data of PbNCN.

High-pressure neutron powder diffraction data from PbNCN were collected on the high-pressure diffraction beamline SNAP located at the Spallation Neutron Source (SNS) of Oak Ridge National Laboratory (Tennessee, USA). The diffraction data were analyzed using the novel method of multidimensional (two dimensions for now, potentially more in the future) Rietveld refinement and, for comparison, employing the conventional Rietveld method. To achieve two-dimensional analysis, a detailed description of the SNAP instrument characteristics was created, serving as an instrument parameter file, and then yielding both cell and spatial parameters as refined under pressure for the first time for solid-state cyanamides/carbodi-imides. The bulk modulus B 0 = 25.1 (15) GPa and its derivative B'0 = 11.1 (8) were extracted for PbNCN following the Vinet equation of state. Surprisingly, an internal transition was observed beyond 2.0 (2) GPa, resulting from switching the bond multiplicities (and bending direction) of the NCN2- complex anion. The results were corroborated using electronic structure calculation from first principles, highlighting both local structural and chemical bonding details.

Demonstration of neutron time-of-flight diffraction with an event-mode imaging detector.

Neutron diffraction beamlines have traditionally relied on deploying large detector arrays of 3He tubes or neutron-sensitive scintillators coupled with photomultipliers to efficiently probe crystallographic and microstructure information of a given material. Given the large upfront cost of custom-made data acquisition systems and the recent scarcity of 3He, new diffraction beamlines or upgrades to existing ones demand innovative approaches. This paper introduces a novel Timepix3-based event-mode imaging neutron diffraction detector system as well as first results of a silicon powder diffraction measurement made at the HIPPO neutron powder diffractometer at the Los Alamos Neutron Science Center. Notably, these initial measurements were conducted simultaneously with the 3He array on HIPPO, enabling direct comparison. Data reduction for this type of data was implemented in the MAUD code, enabling Rietveld analysis. Results from the Timepix3-based setup and HIPPO were benchmarked against McStas simulations, showing good agreement for peak resolution. With further development, systems such as the one presented here may substantially reduce the cost of detector systems for new neutron instrumentation as well as for upgrades of existing beamlines.

Surface diffraction beamline at the SSRF

Surface diffraction beamline at the SSRF

The high flux nano-X-ray diffraction, fluorescence and imaging beamline ID27 for science under extreme conditions on the ESRF Extremely Brilliant Source

ABSTRACT In this overview article, we present the main features of the upgraded ID27 beamline which is fully optimised to match the exceptional characteristics of the new Extremely Bright Source (EBS) of the European Synchrotron Radiation Facility (ESRF). The ID27 beamline has been converted to a 120-m-long instrument and has undergone a major refurbishment of all its critical components including both hardware and software environments. We will successively introduce the ID27 undulator X-ray source, optical scheme and the main components of the experimental hutch. We will illustrate the potential of this new instrument through some selected research examples.

Analytical Scaling Laws for Radiofrequency-Based Pulse Compression in Ultrafast Electron Diffraction Beamlines

We present an envelope equation-based approach to obtain analytical scaling laws for the shortest pulse length achievable using radiofrequency (RF)-based bunch compression. The derived formulas elucidate the dependencies on the electron beam energy and beam charge and reveal how relativistic energies are strongly desirable to obtain bunches containing 1 million electrons with single-digit femtosecond pulse lengths. However, the non-linearities associated with the RF curvature and the beam propagation in drift spaces significantly limit the attainability of extreme compression ratios. Therefore, an additional higher frequency RF cavity is implemented, which linearizes the bunch compression, enabling the generation of ultrashort beams in the sub-femtosecond regime.

New gas system and mass spectrometer for the Powder Diffraction beamline at the Australian Synchrotron

New gas system and mass spectrometer for the Powder Diffraction beamline at the Australian Synchrotron

Structural analysis using both direct- and reciprocal-space data on TPS 19A high-resolution powder X-ray diffraction beamline

Structural analysis using both direct- and reciprocal-space data on TPS 19A high-resolution powder X-ray diffraction beamline

Development of the high energy engineering X-ray (HEX) superconducting wiggler, magnetic measurement, installation, and commissioning.

The High energy Engineering X-ray (HEX) diffraction beamline at the National Synchrotron Light Source II (NSLS-II) at Brookhaven National Lab (BNL) is the first high-energy beamline capable of reaching 200keV for a monochromatic beam. With the 3 GeV electron beam energy for the NSLS-II ring, only the superconducting wiggler (SCW) producing greater than 4T peak field can cover these ranges with a sufficient number of photons. The 1.2 m-long HEX-SCW has a period length of 70mm and a field strength on-axis of 4.3T. It utilizes no liquid helium, and the vertical aperture size of the electron beam vacuum chamber is 8mm. Unlike regular undulators/wigglers, there is no standard configuration for the magnetic measurement system for superconducting insertion devices. The NSLS-II Insertion Devices group has developed, in collaboration with the vacuum group, a novel in-vacuum Hall mapper with a 1.75m in-vacuum linear motor and an in-vacuum flip coil system utilizing many commercial-off-the-shelf products. The measurements were conducted at the BNL, and the device was installed in the ring and commissioned. This paper provides a description of the SCW and its magnetic measurement systems, as well as a brief account of the installation and commissioning efforts.

放射光回折システムの高機能化と機能性材料の開発研究

Driven by improvement of the computer speed and tremendous efforts of crystallographers and equipment manufacturers, X-ray structure analysis has recently become relatively easy and requires no specialized knowledge. On the other hand, synchrotron radiation diffraction experiments have mainly aimed at advanced structural analysis, including electron density analysis, taking advantage of stable and intense X-rays. In recent years, demand for the use of the facility in the materials field has increased, but researchers unfamiliar with synchrotron radiation experiments have felt difficulty in use. Based on my experience in developing conventional diffractometers and software at the equipment manufacturer where I worked after obtaining my degree, I have promoted the development of advanced synchrotron radiation X-ray diffraction systems at SPring-8, a large synchrotron radiation facility. In particular, I have been responsible for the single crystal structure analysis beamline（BL02B1）and the powder diffraction beamline（BL02B2）, which have a wide range of user groups and diverse requirements for instrumental performance, and engaged in instrument development. In addition, I have also worked on structural analysis of functional materials and clarified their structure-function relationships. Among them, I introduce fruitful results on generation process of magnesia cement and design of spin crossover Fe（II）complexes. I believe that such upgrading of synchrotron radiation diffraction systems and development research of functional materials could not be performed without hardware and software knowledge which I learned at the equipment manufacturer.

Virtual-diagnostic-based time stamping for ultrafast electron diffraction

In this work, non-destructive virtual diagnostics are applied to retrieve the electron beam time of arrival and energy in a relativistic ultrafast electron diffraction (UED) beamline using independently-measured machine parameters. This technique has the potential to improve temporal resolution of pump and probe UED scans. Fluctuations in time of arrival have multiple components, including a shot-to-shot jitter and a long-term drift which can be separately addressed by closed loop feedback systems. A linear-regression-based model is used to fit the beam energy and time of arrival and is shown to be able to predict accurately behavior for both on long and short time scales. More advanced time-series analysis based on machine learning techniques can be applied to improve this prediction further.

Specimen-displacement correction for powder X-ray diffraction in Debye-Scherrer geometry with a flat area detector.

The effect of small changes in the speci-men-to-detector distance on the unit-cell parameters is examined for synchrotron powder diffraction in Debye-Scherrer (transmission) geometry with a flat area detector. An analytical correction equationis proposed to fix the shift in 2θ values due to speci-men capillary displacement. This equationdoes not require the use of an internal reference material, is applied during the Rietveld refinement step, and is analogous to the speci-men-displacement correction equations for Bragg-Brentano and curved-detector Debye-Scherrer geometry experiments, but has a different functional form. The 2θ correction equationis compared with another speci-men-displacement correction based on the use of an internal reference material in which new integration and calibration parameters of area-detector images are determined. Example data sets showing the effect of a 3.3 mm speci-men displacement on the unit-cell parameters for 25°C CeO2, including both types of displacement correction, are described. These experiments were performed at powder X-ray diffraction beamlines at the National Synchrotron Light Source II at Brookhaven National Laboratory and the Advanced Photon Source at Argonne National Laboratory.

Total scattering measurements at the Australian Synchrotron Powder Diffraction beamline: capabilities and limitations.

This study describes the capabilities and limitations of carrying out total scattering experiments on the Powder Diffraction (PD) beamline at the Australian Synchrotron, ANSTO. A maximum instrument momentum transfer of 19 Å-1 can be achieved if the data are collected at 21 keV. The results detail how the pair distribution function (PDF) is affected by Qmax, absorption and counting time duration at the PD beamline, and refined structural parameters exemplify how the PDF is affected by these parameters. There are considerations when performing total scattering experiments at the PD beamline, including (1) samples need to be stable during data collection, (2)highly absorbing samples with a μR > 1 always require dilution and (3) only correlation length differences >0.35 Å may be resolved. A case study comparing the PDF atom-atom correlation lengths with EXAFS-derived radial distances of Ni and Pt nanocrystals is also presented, which shows good agreement between the two techniques. The results here can be used as a guide for researchers considering total scattering experiments at the PD beamline or similarly setup beamlines.

A concept of "materials" diffraction and imaging beamline for SKIF: Siberian circular photon source.

Over the next decade, the extremely brilliant fourth generation synchrotron radiation sources are set to become a key driving force in materials characterization and technology development. In this study, we present a conceptual design of a versatile "Materia" diffraction and imaging beamline for a low-emittance synchrotron radiation facility. The beamline was optimized for operation with three main principal delivery regimes: parallel collimated beam ∼1mm beam size, micro-focus regime with ∼10μm beam spot size on the sample, and nano-focus regime with <100nm focus. All regimes will operate in the photon energy range of 10-30keV with the key feature of the beamline being fast switching between them, as well as between the various realizations of diffraction and imaging operation modes while maintaining the target beam position at the sample, and with both spectrally narrow and spectrally broad beams up to the energy band ΔE/E of 5 × 10-2. The manuscript presents the details of the principal characteristics selected for the insertion device and beamline optics, the materials characterization techniques, including the simulations of thermal load impact on the critical beamline optics components. Significant efforts were made to design the monochromators to mitigate the very high beam power load produced by a superconducting undulator source. The manuscript will be of interest to research groups involved in the design of new synchrotron beamlines.

Etched Silicon Planar CRL Optics for the High-Energy X-ray Diffraction Beamlines 11-ID-B and 11-ID-C at the APS

The focusing of high-energy X-rays is most commonly achieved by commercially available compound refractive lenses (CRL), which are added together in larger structures. There is a need for high-energy X-ray beamlines to enable focusing in only one dimension down to a few micrometers to study layered materials and thin films. High-energy X-rays above 50 keV require often 100 lenses or more, therefore it is more efficient to etch the complete arrays of lenses into a monolithic substrate like a silicon wafer. Custom lens arrays were fabricated for the high-energy x-ray beamlines 11-ID-B, and 11-ID-C at the Argonne National Laboratory. The fabrication required tuning parameters of the Bosch process to optimize the etching of deep vertical sidewalls at a reasonable speed without overheating. The beamline 11-ID-B is equipped with lens arrays of 85-110 lenses for 59 keV and 190-250 lenses for 87 keV photon energy, focusing the beam vertically below 5.0 µm at the sample positions between 1600 mm to 2100 mm. 11-ID-C has received arrays of 435 lenses that focus 106 keV X-rays to a vertical height of 2.0 µm at the sample position. In both cases, the flux density gain in the focal spot is larger than a factor of 20, relative to using slits to cut the beam size. The lens setup is permanently installed and can be moved in and out of the beam during the experiment without further alignment. The lenses have enabled operando diffraction studies on interfaces in batteries and the development of pair distribution function (PDF) analysis using grazing incidence geometry.

A grazing incidence diffraction setup for Langmuir trough experiments at the high-resolution diffraction beamline P08 at PETRA III

The Langmuir Grazing Incidence Diffraction setup at the high-resolution diffraction beamline P08 of PETRA III is a dedicated setup for grazing incidence X-ray scattering measurements on Langmuir troughs. The instrument is optimized for low background grazing incidence X-ray diffraction measurements at vapour-water interfaces, while offering rapid layer structure assessment by grazing incidence X-ray off-specular scattering, and interfacial element analysis by total reflection X-ray fluorescence spectroscopy. Its control system is intuitive and standardized to provide easy access for non-expert users, and permits automated operation except for sample exchange.

MeV electron bunch compression and timing jitter suppression using a THz-driven resonator

THz-driven electron bunch compression and manipulation have significantly progressed and shown great potential in recent years. This paper presents a THz-driven resonator capable of bunch compression and timing jitter suppression with the inherent advantages such as field enhancement and laser synchronization. The resonance behavior of the resonator is studied to deduce the expression of the resonance frequency. Using the particle-tracking simulation, we study the performance of the THz-driven resonator in a MeV ultrafast electron diffraction beamline, and conclude that a bunch length (rms) of 15.40 ± 4.86 fs and timing jitter of 10.1 fs (rms) is achievable, which enables a temporal resolution below 25 fs in theory. Moreover, the THz-regime resonating field in the THz resonator allows for direct manipulation of each microbunch of a bunch train with picosecond bunch spacing. Particle-tracking simulation shows that simultaneous multi-bunch compression can be realized with a frequency-customized THz resonator. We expect this novel method to be applied in multi-bunch applications such as the coherent Smith–Purcell radiation.

Construction of Cryogen-Free 4.3T Superconducting Wiggler for NSLS-II Ring

With the 3 GeV electron beam energy for the National Synchro-tron Light Source II (NSLS-II) ring, only superconducting wig-glers (SCW) producing greater than 4T peak field can cover the photon energy range of 20keV and 200keV with sufficient num-ber of photons. The High energy Engineering X-ray (HEX) Dif-fraction beamline, which is primarily funded by the New York State Energy Research and Development Authority (NYSERDA) and NSLS-II, will be equipped with a 1.2m-long SCW with 70mm period length and 4.3T on-axis field. This SCW is free from the use of liquid Helium and is cooled only with cryo-coolers. The Electron Beam Chamber (EBC) with vertical aper-ture of 8mm is made from 316LN stainless steel and copper plat-ing is applied both entire upper surface and +- 12.5mm wide from the center in the inner surface. The expected heat load from the electron beam of the NSLS-II ring is estimated to be 10W/m. This paper describes the design principles and engineering chal-lenges for the device.

Tristan10M detector: characterization of a large area detector for time resolved experiments based on Timepix3 chip

Tristan10M is a 10-million-pixel large area detector based on the Timepix3 ASIC. The Timepix3 ASIC can work in event driven mode in addition to the standard frame based mode. Thanks to these capabilities of the Timepix3 ASIC, the Tristan detector is ideal for time-resolved experiments. The Tristan 10M detector is organized in a 2 × 5 module matrix, each module being made up of sixteen Timepix3 chips bump-bonded to a monolithic pixelated silicon sensor. In this contribution, we will report on the status of the detector development, and characterization results in terms of threshold equalization, energy calibration, and flat-field correction. A number of initial commissioning experiments have been carried out on the small molecule single crystal diffraction beamline I19 at Diamond light source, which we will also report on here. In particular, X-ray powder diffraction from a standard sample, LaB6, was performed to evaluate the inter-module alignment based on per-module basis.