Micro-focus X-ray Diffractometry for Time Resolved Structure Analysis -A Development of X-ray Pinpoint Structural Measurement at the SPring-8 (1)

Research and Utilization Division, Japan Synchrotron Radiation Research Institute (JASRI/SPring-8)/CREST* Department of Physical Science, Hiroshima University/CREST** The Graduate School of Pure and Applied Sciences, Tsukuba University/CREST*** RIKEN/CREST**** Graduate School of Material Science, University of Hyogo/CREST***** RIKEN (JASRI/SPring-8)/CREST******
○Haruno Murayama* Nobuhiro Yasuda* Jungeun Kim* Yoshimitsu Fukuyama* Shigeru Kimura* Yoshihiro Kuroiwa** Kenichi Kato* Yutaka Moritomo*** Yoshihito Tanaka**** Koshiro Toriumi***** Masaki Takata******

The study of dynamic structures is important to characterize nano-materials and their events such as amorphous-crystal change on recording DVD media and photo-induced metal-insulator transition. For these researches, we are developing X-ray pinpoint structural measurement technique, which is XRD measurement system in ~100 nm spatial resolution and ~40 ps time resolution with focusing X-ray by a zone plate.
High brilliant pulse X-ray emanating from insertion device of the SPring-8 is powerful tool for a time resolved measurement using single pulse X-ray. The pinpoint X-ray structural measurement system has been constructed on the high flux beam line using a helical undulator, BL40XU at the SPring-8. About 100nm focused beam can be produced by a high resolution type standard Fresnel zone plate,ZP2, whose Ta thickness is 0.75 μm. For 8 keV X-rays, the ideal X-ray diffraction efficiency is 12 %. To increase X-ray diffraction efficiency, a high flux type, ZP1, whose Ta thickness is 2.5 μm, was designed. The ZP1 achieved the diffraction efficiency up to 20 %. The beam size and flux per unit area of 15 keV X-ray was 1.4x2.4 μm2 and 3x1014 photons・s-1・mm-2, respectively. In order to align micro-beam with sub-micron size crystal, high precision two circle goniomator, whose decentering error is within ±100 nm/360°were constructed with CCD or IP detector. A femto/picosecond pulse laser (Ti:sapphire oscillator, λ=800nm) system is equipped on the diffractomator for a photo-irradiation pump and probe experiment using X-ray pulse selector. The details of the instruments and performance of the X-ray pinpoint structural measurement system will be presented.