Shunji Goto

Construction and commissioning of a 215-m-long beamline at SPring-8

Abstract The 215-m-long beamline has been constructed as the first medium-length beamline of SPring-8 for the purpose of R&D of imaging techniques, development of X-ray optics, computed tomography for mineral science, medical imaging, and X-ray topography. By using the long beamline, large field and spatially coherent beam can be obtained. Advantage of long beamline is successfully demonstrated by the preliminary experiment such as one-shot topograph of 300-mm-diameter silicon crystal.

HELICITY-MODULATION TECHNIQUE USING DIFFRACTIVE PHASE RETARDER FOR MEASUREMENTS OF X-RAY MAGNETIC CIRCULAR DICHROISM

A diamond X-ray phase retarder has been combined with a phase-sensitive detection method to improve the accuracy of X-ray magnetic circular dichroism (XMCD) measurements. Fluctuation of the absorption coefficient of a magnetized sample was induced by photon-helicity switching at 40 Hz by flipping the phase retarder, and directly detected through a lock-in amplifier referring to the helicity-modulation frequency. This new technique for XMCD measurements was applied to the Fe K-edge in pure Fe foil. XMCD spectra of higher signal-to-noise ratio were obtained in shorter measuring time.

Construction and Commissioning of A 248 m‐long Beamline with X‐ray Undulator Light Source

A medium‐length beamline with undulator source, BL20XU at SPring‐8, was constructed, and opened to public use. The distance from source point to the end of the beamline is 248 m. By utilizing the long beam transport path, the beamline has advantages for experiment that requires high spatial coherence in hard X‐ray regions.

Construction and Commissioning of BL37XU at SPring-8

Trace element analysis beamline (BL37XU) at SPring‐8 was designed for application to various X‐ray fluorescence analyses such as XRF imaging, XAFS, TXRF and XRF holography. The beamline has of two branches, one being a SPring‐8 standard undulator‐beamline optics branch (Branch A) and the other a high‐energy branch (Branch B). In the experimental hutches, several kinds of experimental device are equipped. The end‐stations have been opened to public use since November 2002, and various experiments have been carried out.

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.

SPring-8 standard x-ray monochromators

Most SPring-8 x-ray beamlines are installed double-crystal monochromators that are standardized. For x-ray undulator beamlines where power density of the beam are quite high, rotated-inclined double-crystal geometry is usually adopted, which enlarges the footprint of the incident beam on the crystal surface to reduce the power density. On the other hand, adjustable-inclined double-crystal geometry is adopted for bending-magnet beamlines to extend the available energy range with a limited Bragg angle range. The standardized monochromator mechanism is compatible to both of the geometries, only by changing crystal mounts. Detailed description of the monochromator mechanism is presented.

New soft X-ray beamline BL07LSU at SPring-8

The design and performance of a new soft X-ray beamline BL07LSU at SPring-8 are described. The combination of a novel segmented cross undulator and beamline monochromator has achieved high energy resolution (E/ΔE > 10000) and high photon flux [>1012 photons s−1 (0.01% bandwidth)−1] in the photon energy range 250–2000 eV with fully controllable polarization.

1-km beamline at SPring-8

A one-kilometer long synchrotron radiation beamline with an x- ray undulator source was completed at SPring-8. The beamline was planned to facilitate various applications of a wide-area coherent x-ray beam, development of bi-crystal x-ray interferometers for gravitational red-shift measurement and development of highly sensitive diagnostic methods of accelerator dynamics. This paper reports the structure of the long beamline as well as some selected first results including phase contrast imaging and diffraction imaging applications.

Response functions of a Si(Li) detector for photon energies from 1 to 10 keV

Abstract We report the effect of incomplete carrier collection on response functions of a Si(Li) detector for photon energies from 1 to 10 keV. We calculate carrier collection probability as a function of generated carrier position using a simple model including drift, diffusion, and reflection at the gold-silicon interface. We simulate the energy loss of secondary electrons generated by photoabsorption in the silicon and the gold contact using a Monte Carlo method. Calculated response functions agreed well with measured ones over the entire energy range. We explain the threshold of the low-energy tail, observed for photon energies just above the Si K absorption edge, using a carrier reflection model. We also explain the flat continuum by secondary electrons escaping from the silicon to the gold contact and penetrating the silicon from the gold contact.

Construction and performance of a figure-8 undulator

The figure-8 undulator is a novel insertion device adopted as a light source at the soft x-ray photochemistry beamline of the Super Photon ring-8GeV. It was designed to produce linearly polarized soft x rays between 100 and 5000 eV with low on-axis power density. Magnetic fields of the constructed device were measured with compensation for the planar Hall effect using two different methods. After magnetic-field corrections, it was found that the first-harmonic intensity and the on-axis power density calculated using the measured fields were almost the same as ideal ones. After installation in the storage ring, a power-distribution pattern was observed by a fluorescent screen and it was found that the shape corresponded to expectation. The quantity of fluctuation of the photon-beam axis was estimated by measuring spectra at various observation angles and it was found to be small compared to the photon-beam size. In addition, it was also found that the measured spectrum at the gap of 77 mm agreed well with ...