E. Ishiguro

Outline of soft X-ray photochemistry beamline BL27SU of SPring-8

Abstract BL27SU of SPring-8 was constructed for soft X-ray photochemistry. To perform different types of experiments, BL27SU has three branches. In a branch for spectroscopic experiments, a monochromator of very high energy resolving power was required. The other branches were built for experiments in need of high flux rather than energy resolution. In this report the optics and some apparatuses for photochemistry installed in BL27SU are presented.

Performance of a Highly Stabilized and High-resolution Beamline BL17SU for Advanced Soft X-ray Spectroscopy at SPring-8

A new soft x‐ray beamline BL17SU (RIKEN) has been constructed at SPring‐8. The beamline consists of two branches with each varied‐line‐spacing‐plane‐grating‐monochromator. Both monochromators perform high energy resolution (E/ΔE > 10,000) between 0.2 and 1 keV. One of the monochromator achieves high energy stability of 10 meV over a period of half a day.

Performance of a grating monochromator at BL27SU beamline of SPring-8 in the higher energy region

Performance tests were carried out on a varied line-spacing plane grating monochromator at BL27SU of SPring-8 in the higher energy region using photoabsorption spectra of gas and solid samples and photoelectron spectra of Xe 5p3/2. A flux of 1×1011 photons/s/100 mA/0.02% b.w. was achieved at 2 keV. The photon flux steeply decreased above 2 keV to 5×109 photons/s/100 mA/0.02% b.w. at 2.8 keV.

DESIGN OF A FLAT FIELD SPECTROMETER FOR SOFT X-RAY EMISSION SPECTROSCOPY

A spectrometer for soft X-ray emission spectroscopy was designed and constructed. The aims of this spectrometer are high detection efficiency and realizing the energy resolution of 1000 (E/ΔE) in a compact size. To satisfy these requirements, a flat field spectrometer with a varied line spacing grating and a CCD detector was chosen. Furthermore, the configuration without the entrance slit was employed. For compact flat field spectrometers, the spectral dispersion on the detector is sometimes smaller than the spatial resolution of existing detectors restricting maximum energy resolution. The spectral dispersion on the detector was optimized to balance with the spatial resolution of CCD. Optical performance was tested with a ray-tracing program. The spectrometer covers 250–900 eV, with two gratings. Taking into account the spatial resolution of a CCD detector, the maximum energy resolution of the spectrometer is estimated to be about 1000 (E/ΔE) for the beam size of 10 μm. Using the constructed spectrometer, test experiments were performed at the beamline BL27SU in SPring-8.

Soft X-ray photochemistry beamline at SPring-8.

Design and construction of a soft X-ray beamline at SPring-8 is reported. The beamline utilizes high-quality linearly polarized soft X-rays obtainable from a figure-8 undulator for the study of photophysical and photochemical processes of atoms, molecules and surfaces in the inner-shell excitation region. It consists of two experimental stations, a photochemistry station and a chemical vapour deposition (CVD) station. A high-resolution grating monochromator is installed at the photochemistry station, while the intense undispersed undulator radiation is used at the CVD station. Unique features of the experimental chambers and of the analysis and characterization systems are described along with those of the monochromator.

ELECTRONIC STRUCTURES OF POLYSILANES AND RELATED COMPOUNDS

UPS and Si K- and LII,III-edge NEXAFS spectra of various polysilanes, poly(dimethylsiloxane), and octakis(t-butyl)octa-silacubane (OTBOSC) were measured for elucidating their occupied and vacant electronic structures, in comparison with the results for polysilazane. The results revealed that the electronic structures are sensitive for the main chain structure, pendant, and the dimensionality of the Si-containing backbone.

Angle-resolved electron and ion spectroscopy apparatus on the soft X-ray photochemistry beamline BL27SU at SPring-8

Abstract We have designed and constructed the apparatus for the angular distribution measurements of photoejected electrons and ions from free molecules, as a part of the endstation of the c -branch of the beamline BL27SU, a soft X-ray photochemistry beamline at SPring-8. The experimental procedures are described in combination with the use of a capability to switch the horizontal and vertical directions of the linear polarization of the light produced by the figure-8 undulator. As a typical example of the experimental results, we present angle-resolved energetic ion yield spectra in the O 1s excitation region of CO 2 .

Aspherically bent SiC mirror: Bending test

Abstract A bending test of an elliptically bent SiC mirror was performed. The result shows that a desired figure of the surface can be generated with a high accuracy by using a simple bending mechanism.

Performance of refocusing mirrors for a soft X‐ray photochemistry beamline BL27SU of SPring‐8

Refocusing mirrors were designed and equipped in the high‐resolution branch of BL27SU in SPring‐8. It is required to switch quickly among the three tandem end‐stations and achieve a vertical size of less than 10 microns at one experimental station. Two toroidal mirrors and a set of two cylindrical mirrors were employed in order to align them easily. The beam size and photon flux were measured.

A UHV Apparatus for Soft X‐ray Spectroscopy with Symmetry Selection for Solids and Surfaces

A UHV apparatus for soft x‐ray spectroscopic studies on solids and surfaces has been constructed at the beamline BL27SU in SPring‐8. A newly developed flat field spectrometer with a CCD detector is equipped for soft X‐ray emission spectroscopy (SXES). The focused beam, less than 10μm in vertical direction, enables us to take entrance slit of the spectrometer away, and to achieve high detection efficiency without loss of incident beam. The energy resolution (E/ΔE) of around 1000 is realized in the energy range of 250–900 eV. An electron energy analyzer is also equipped for photoelectron spectroscopy (PES). An undulator called “Figure‐8” at this beamline supplies both horizontally and vertically polarized soft x‐rays so that we can get symmetry resolved SXES and PES spectra with ease by changing the polarization.