Shanghai Synchrotron Radiation Facility Research Articles

Efficient Electronic Modulation of g-C 3 N 4 Photocatalyst by Implanting Atomically Dispersed Ag 1 -N 3 for Extremely High Hydrogen Evolution Rates

Efficient Electronic Modulation of g-C ₃ N ₄ Photocatalyst by Implanting Atomically Dispersed Ag ₁ -N ₃ for Extremely High Hydrogen Evolution Rates

Precise Construction of Stable Bimetallic Metal–Organic Frameworks with Single-Site Ti(IV) Incorporation in Nodes for Efficient Photocatalytic Oxygen Evolution

Precise Construction of Stable Bimetallic Metal–Organic Frameworks with Single-Site Ti(IV) Incorporation in Nodes for Efficient Photocatalytic Oxygen Evolution

Systematic Investigation of Solution-State Aggregation Effect on Electrical Conductivity in Doped Conjugated Polymers

Systematic Investigation of Solution-State Aggregation Effect on Electrical Conductivity in Doped Conjugated Polymers

Photoemission Spectroscopic Evidence of Multiple Dirac Cones in Superconducting BaSn3 Supported by the National Key R&D Program of China (Grant No. 2016YFA0300204), the National Natural Science Foundation of China (Grant Nos. U2032208 and 11874264), and the Natural Science Foundation of Shanghai (Grant No. 14ZR1447600). Y. F. Guo acknowledges the starting grant of ShanghaiTech University and the Program for Professor of

Signatures of topological superconductivity (TSC) in superconducting materials with topological nontrivial states prompt intensive researches recently. Utilizing high-resolution angle-resolved photoemission spectroscopy and first-principles calculations, we demonstrate multiple Dirac fermions and surface states in superconductor BaSn3 with a critical transition temperature of about 4.4 K. We predict and then unveil the existence of two pairs of type-I topological Dirac fermions residing on the rotational axis. Type-II Dirac fermions protected by screw axis are confirmed in the same compound. Further calculation for the spin helical texture of the observed surface states originating from the Dirac fermions gives an opportunity for realization of TSC in one single material. Hosting multiple Dirac fermions and topological surface states, the intrinsic superconductor BaSn3 is expected to be a new platform for further investigation of topological quantum materials as well as TSC.

Extreme Ultraviolet Photoresist Inspection Platform in Shanghai Synchrotron Radiation Facility

Extreme Ultraviolet Photoresist Inspection Platform in Shanghai Synchrotron Radiation Facility

Bunch-by-bunch beam lifetime measurement at SSRF

Lifetime is a key performance parameter of storage rings. DC current transformers (DCCT) are common employed to measure beam lifetime, which can only be applied to measure average lifetime. However, the physical lifetime formula is only strictly established for a single bunch. In order to provides a toolkit for complete and accurate representation of the behavior of all electron bunches, a bunch-by-bunch beam lifetime measurement system has been developed at the Shanghai Synchrotron Radiation Facility. A beam-position-monitor was used as the detector of beam-charge-monitor. Several effective techniques have been introduced to improve the resolution and data refresh rate of the single bunch charge measurement. Resolution of the new bunch-by-bunch charge monitor is better than 0.02% and data refresh rate is 140 Hz. A dedicated algorithm has been developed to extract lifetime of single bunch. Resolution of bunch-by-bunch vacuum lifetime measurement is 1 h. System setup, experiments and data analysis are presented in this paper.

Luminescent properties and X-ray imaging result of Lu2O3:Eu structured scintillation film on YSZ single crystal substrate by LCVD method

Micro-columnar structured europium doped lutecia (Lu2O3:Eu) scintillation film is one of the most attractive candidate materials for high-energy hard X-ray imaging detectors because of their excellent physical, scintillation properties and light guide effect. Lu2O3:Eu micro-columnar film (MCF) with 9 μm thickness was obtained on a yttrium stabilized zirconia (YSZ) (100) single crystal substrate by laser chemical vapor deposition (LCVD), and its structure, morphology, photoluminescence and scintillation properties were characterized. The structure and morphology of obtained film were investigated by grazing incidence X-ray diffraction (GIXRD) and scan electron microscopy (SEM). The photoluminescence and scintillation properties, including photoluminescence excitation (PLE), photoluminescence (PL), PL decay, X-ray excited luminescence (XEL), were measured and discussed. The X-ray imaging result of Lu2O3:Eu MCF on YSZ substrate was obtained for the first time and spatial resolution of 2 μm was obtained at BL13W beamline at Shanghai synchrotron radiation facility (SSRF).

New noninvasive measurement method of optics parameters in a storage ring using bunch-by-bunch 3D beam position measurement data

In order to improve machine performance, the optics parameters of the storage ring need to be measured accurately. The commonly used accelerator optics parameters, including momentum compaction factor and dispersion function, are key parameters that reflect the state of the machine. It is difficult to measure them with traditional methods during the user operation run. Based on a high-resolution bunch-by-bunch three-dimensional measurement system, a noninvasive measurement of momentum compaction factor and the dispersion function was performed at the Shanghai synchrotron radiation facility (SSRF). The dispersion function can be obtained purely from the direct observation results of the bunch-by bunch 3D position, based on the definition of the dispersion function during normal user operation run without perturbing the beam. The theoretical background and experimental results of the method are discussed in this paper. The measurement results are in good agreement with the design values.

Partial Order–Disorder Transformation of Interpenetrated Porous Coordination Polymers

Controlling interpenetration and flexibility behaviors is intriguing and fundamental for porous coordination polymers. We report exceptional interpenetration behaviors involving controllable partia...

One-Pot Synthesis of Supertough, Sustainable Polyester Thermoplastic Elastomers Using Block-Like, Gradient Copolymer as Soft Midblock

It remains challenging to synthesize supertough thermoplastic elastomers (TPEs) since the stretchability and tensile strength are mutually exclusive. Here, we report a one-pot strategy for the prep...

Development of micro-Laue technique at Shanghai Synchrotron Radiation Facility for materials sciences

Synchrotron radiation-based micro-Laue technique has showcased great application potentials in materials science study for its unprecedented crystal orientation and lattice strain/stress resolution. Here we report the updated progress in the development of the micro-Laue technique on the X-ray test beamline at Shanghai Synchrotron Radiation Facility. So far, 40 µm (h) × 50 µm (v) X-ray beam spot is routinely obtained, with the convergent angle of 0.2 mrad (h) × 0.12 mrad (v). Area scans are conducted on a GH3535 Ni-based superalloy base metal and weld joint with the same chemical composition. By analyzing the tremendous amount of Laue diffraction patterns using in-house developed software packages, the crystal orientation, elastic strain, and defect distributions are mapped and investigated. Such a successful proof-of-principle study offers first-hand experience on the further optimization of the design and construction of the scanning micro-Laue facility on the superbend beamline with improved spatial resolution and multiple functions for simultaneous chemical fluorescence mapping and in-situ microstructural evolution studies. The micro-Laue diffraction beamline at Shanghai Synchrotron Radiation Facility will provide a versatile and powerful tool for the orientation and strain/stress mapping combined with phase identification with micron-sized spatial resolution.

Deploying the Big Data Science Center at the Shanghai Synchrotron Radiation Facility: the first superfacility platform in China

With recent technological advances, large-scale experimental facilities generate huge datasets, into the petabyte range, every year, thereby creating the Big Data deluge effect. Data management, including the collection, management, and curation of these large datasets, is a significantly intensive precursor step in relation to the data analysis that underpins scientific investigations. The rise of artificial intelligence (AI), machine learning (ML), and robotic automation has changed the landscape for experimental facilities, producing a paradigm shift in how different datasets are leveraged for improved intelligence, operation, and data analysis. Therefore, such facilities, known as superfacilities, which fully enable user science while addressing the challenges of the Big Data deluge, are critical for the scientific community. In this work, we discuss the process of setting up the Big Data Science Center within the Shanghai Synchrotron Radiation Facility (SSRF), China’s first superfacility. We provide details of our initiatives for enabling user science at SSRF, with particular consideration given to recent developments in AI, ML, and robotic automation.

New Cage-Like Cerium Trihydride Stabilized at Ambient Conditions

New Cage-Like Cerium Trihydride Stabilized at Ambient Conditions

Analysis of partially coherent light propagation through the soft X-ray interference lithography beamline at SSRF.

The mutual optical intensity (MOI) model is extended to the simulation of the interference pattern produced by extreme ultraviolet lithography with partially coherent light. The partially coherent X-ray propagation through the BL08U1B beamline at Shanghai Synchrotron Radiation Facility is analysed using the MOI model and SRW (Synchrotron Radiation Workshop) method. The fringe intensity at the exposure area is not uniform but has similar envelope lines to Fresnel diffraction, which is explained by the diffraction from the finite grating modelled as a single aperture. By balancing the slit size and photon stop size, the fringe visibility, photon flux and intensity slope can be optimized. Further analysis shows that the effect of pink light on the aerial images is negligible, whereas the third-harmonic light should be considered to obtain a balance between high fringe visibility and high flux. Two grating interference exposure experiments were performed in the BL08U1B beamline. The aerial image depth showed that the polymethyl methacrylate photoresist depth was determined by the X-ray coherence properties.

Saturation curves of low-voltage ionization chamber for ITER at 10–30 keV

A low voltage ionization chamber (LVIC) is a very promising alternative to ITER X-ray detectors owing to its outstanding radiation tolerance. To investigate the characteristics of the LVIC preliminary prototype and evaluate its application in ITER, the saturation curves corresponding to 10–30 keV monochromatic radiations were measured in the Shanghai Synchrotron Radiation Facility. In the saturation region, the output current variation was linear with respect to input power, indicating that the LVIC can be used to detect X-ray emissions. Based on the saturation curves and related simulation, it is speculated that the saturation voltages needed for LVICs of the external and internal cameras in ITER might be no greater than 150 V and 300 V respectively. Responsivity (R) derived from experimental results was compared with theoretical calculations, showing good agreement at 15–20 keV, but significant deviations at 10 keV and 30 keV, which will be studied in the future. It is estimated that R of the LVIC ranges from 2.66 × 10−2 to 1.89 × 10−3 A/W between 10 to 30 keV. The experimental results show promising potential for LVIC application in ITER as an X-ray detector.

The Enhancement of Selectivity and Activity for Two-Electron Oxygen Reduction Reaction by Tuned Oxygen Defects on Amorphous Hydroxide Catalysts

Amorphous catalysts, thanks to their unique coordinately unsaturated properties and abundant of defect sites, incline to possess higher activity and selectivity than their crystalline counterparts....

Bunch-by-bunch three-dimensional position and charge measurement in a storage ring

Bunch-by-bunch beam parameters monitor is a very useful tool for accelerator operation and optimization. An in situ bunch-by-bunch three-dimensional position and charge measurement system has been developed at the Shanghai Synchrotron Radiation Facility. Signals from beam position monitors carry almost full beam information, a broadband digital receiver can retain most information. Therefore, a four-channel wideband oscilloscope is employed to capture the signals from all electrodes of the beam position monitor. Correlation coefficient-based methods are used to extract these bunch-by-bunch parameters synchronously. We evaluated the performance of this bunch-by-bunch information extraction method, the measurement uncertainty of longitudinal phase is less than 0.2 ps, the uncertainty of transverse position is less than $10\text{ }\text{ }\ensuremath{\mu}\mathrm{m}$ and the charge uncertainty is 0.3% under the condition that the bunch charge is 600 pC. Thanks to the great performance of the new system, it is accurate enough to study the transient state during injection. In addition, an in situ wakefield measurement system is planned to be established based on this system.

Application of machine learning in orbital correction of storage ring

Synchrotron light source is one of the most powerful tools in modern science and technology. Shanghai Synchrotron Radiation Facility (SSRF), located in Shanghai, China, is an advanced 3.5 GeV 3rd-generation medium energy light source. The 3rd-generation synchrotron radiation light source will provide high brilliance and high stability synchrotron radiation to fulfill the advanced experimental conditions in frontier researches. To achieve highly stable radiation, it is important to have highly stable beam orbit. Thus we adopted machine learning method to control and feedback the orbit. Using this neural network-based orbit correction method, which doesn’t rely on the response matrix, we can establish a nonlinear mapping relationship between correctors and the orbit distortions and perform continuous online retraining. This new method can significantly improve the orbit stability of SSRF.

High-resolution ARPES endstation for in situ electronic structure investigations at SSRF

Angle-resolved photoemission spectroscopy (ARPES) is one of the most powerful experimental techniques in condensed matter physics. Synchrotron ARPES, which uses photons with high flux and continuously tunable energy, has become particularly important. However, an excellent synchrotron ARPES system must have features such as a small beam spot, super-high energy resolution, and a user-friendly operation interface. A synchrotron beamline and an endstation (BL03U) were designed and constructed at the Shanghai Synchrotron Radiation Facility. The beam spot size at the sample position is 7.5 (V) μm × 67 (H) μm, and the fundamental photon range is 7–165 eV; the ARPES system enables photoemission with an energy resolution of 2.67 meV at 21.2 eV. In addition, the ARPES system of this endstation is equipped with a six-axis cryogenic sample manipulator (the lowest temperature is 7 K) and is integrated with an oxide molecular beam epitaxy system and a scanning tunneling microscope, which can provide an advanced platform for in situ characterization of the fine electronic structure of condensed matter.

Development of a Test Cryostat for a Superconducting Undulator Prototype at the SSRF

The superconducting undulator (SCU) is a trend to be applied for future light sources to obtain the higher light brilliance. A planar SCU prototype with a period of 16 mm, a magnetic gap of 9.5 mm and 50-periods magnet has been under development at the Shanghai Synchrotron Radiation Facility (SSRF) since late 2013. The key technologies including magnet cooling, coil winding, low-temperature alignment of magnet and beam tube, and cryogenic magnetic field measurement have been investigated. A cryocooler-cooled test cryostat was developed for the purpose of both experimentally studying the key technologies and testing the performance of the SCU prototype. Two-stage cryocoolers were applied for cool down, helium liquefaction and keeping the SCU cooled at operation. The SCU magnet and the UHV beam tube were cooled separately. The magnet working at 4.2 K is cooled by thermosiphon-driven liquid helium flowing through the piping in the magnet mandrel. The beam tube, thermal shields and binary leads were conduction-cooled. The beam tube will work at between 4.2 K and 20 K up to dynamic loads generated by the SSRF beam. A set of improved self-centered support assembly for the magnet was developed in order to avoid the complex alignment at low temperature and lower down the machining cost. A cooling approach to effectively cool the junction of the binary lead made of copper and HTS lead commonly used in cryocooler-cooled superconducting systems was adopted and validated. The cryostat was successfully debugged and run at the early of 2016. This paper describes the design details of the cryostat including new approaches to cool the SCU and the binary leads, its fabrication and test results.