High-energy x-rays from a synchrotron radiation source allow us to obtain high-quality diffraction data for disordered materials from ambient to extreme conditions, which is necessary for revealing the detailed structures of glass, liquid and amorphous materials. We introduced high-energy x-ray diffraction beamlines and a dedicated diffractometer for glass, liquid and amorphous materials at SPring-8 and report the recent developments of ancillary equipment. Furthermore, the structures of liquid and amorphous materials determined from the high-energy x-ray diffraction data obtained at SPring-8 are discussed.

https://iopscience.iop.org/article/10.1088/0953-8984/19/50/506101/pdf

Structural studies of disordered materials using high-energy x-ray diffraction from ambient to extreme conditions

Micro-crystallography comes of age.

A new beamline called the frontier soft-material beamline at BL03XU for soft materials was recently installed at SPring-8, using an in-vacuum undulator. The photon flux can reach 1013 photons sec−1 and the energy resolution is about 10−4 at an energy of 12.4 keV. The present paper introduces details on the instrumental and some of the first scattering data measured at BL03XU, revealing its cutting-edge design and high performance.

/pdf/multipurpose-soft-material-saxs-waxs-gisaxs-beamline-at-5200l071e1.pdf

Multipurpose soft-material SAXS/WAXS/GISAXS beamline at SPring-8

An energy-domain 57Fe-Mossbauer spectrometer using synchrotron radiation (SR) with a diamond anvil cell (DAC) has been developed for ultrahigh-pressure measurements. The main optical system consists of a single-line pure nuclear Bragg reflection from an oscillating 57FeBO3 single crystal near the Neel temperature and an X-ray focusing device. The developed spectrometer can filter the Doppler-shifted single-line 57Fe-Mossbauer radiation with a narrow bandwidth of neV order from a broadband SR source. The focused incident X-rays make it easy to measure a small specimen in the DAC. The present paper introduces the design and performance of the SR 57Fe-Mossbauer spectrometer and its demonstrative applications including the newly discovered result of a pressure-induced magnetic phase transition of polycrystalline 57Fe3BO6 and an unknown high-pressure phase of Gd57Fe2 alloy placed in a DAC under high pressures up to 302 GPa. The achievement of Mossbauer spectroscopy in the multimegabar range is of particular interest to researchers studying the nature of the Earth's core.

Development of an energy-domain 57Fe-Mössbauer spectrometer using synchrotron radiation and its application to ultrahigh-pressure studies with a diamond anvil cell.

An X-ray magnetic circular dichroism experiment under multiple extreme conditions, 2 <or= T <or= 300 K, H <or= 10 T and P <or= 50 GPa, has been achieved at SPring-8 BL39XU. A combination of the high-brilliant X-ray beam and a helicity-controlled technique enabled the dichroic signal to be recorded with high accuracy. The performance is shown by the outcome of pressure-induced ferromagnetism in Mn(3)GaC and the pressure-suppressed Co moment in ErCo(2). Two technical developments, a tiny diamond anvil cell inserted into a superconducting magnet and in situ pressure calibration using 90 degrees Bragg diffraction from a NaCl marker, are also presented. X-ray magnetic spectroscopy under multiple extreme conditions is now opening a new approach to materials science.

X-ray magnetic spectroscopy at high pressure: performance of SPring-8 BL39XU.

Top-up operation allows SPring-8 to provide highly stable X-ray beams with arbitrary filling patterns. The implementation of top-up operation is described, with a focus on the simultaneous achievement of stability of stored current, beam orbit, purity of an isolated single bunch, and beam injection efficiency. Stored-current fluctuations have been routinely reduced to a level of 10−3. Stored-beam oscillation on frequent beam injection, which was originally regarded as the most serious problem, has been successfully suppressed to a sufficiently low level that it never perturbs imaging experiments. Current impurities in nominally empty buckets have been reduced to a level of 10−9 over more than one week of operation, making possible the measurement of time-resolved spectra using high-current bunches. Finally, excellent injection efficiency, higher than 80%, is routinely obtained, even for small undulator gaps, which is critical for preventing radiation damage to insertion-device magnets and to reduce leakage radiation. The process of achieving highly stabilized top-up operation at SPring-8 and its utility for user experiments are described.

https://journals.iucr.org/s/issues/2006/05/00/wr5003/wr5003.pdf

Naoyasu Hosoda

Papers

Stable top-up operation at SPring-8