日本地球惑星科学連合2019年大会

講演情報

[J] ポスター発表

セッション記号 U (ユニオン) » ユニオン

[U-04] 地球惑星科学における高速過程を捉える

2019年5月29日(水) 17:15 〜 18:30 ポスター会場 (幕張メッセ国際展示場 8ホール)

コンビーナ:芳野 極(岡山大学惑星物質研究所)、丹下 慶範(高輝度光科学研究センター)

[U04-P01] X線吸収分光法を利用したSPring-8における時間分解計測の現状

*新田 清文1関澤 央輝1加藤 和男1大沢 仁志1 (1.公益財団法人高輝度光科学研究センター)

キーワード:X線吸収分光法、時間分解、放射光

X-ray Absorption Fine Structure (XAFS) is powerful tool to investigate electric structure and local structure around X-ray absorption atom. Time resolved XAFS measurement developed from appearance of synchrotron radiation and have been applied to many fields. For example, time-resolved XAFS is applied for the catalytic reaction at the in-situ condition and give us the information about how the chemical reaction progresses. We will introduce three representative time-resolved XAFS measurement.

(Super) Quick XAFS (QXAFS),
In QXAFS, the monochromator sweeps quickly (or oscillates at high frequency in Super QXAFS) and it measures the incident X-ray and transmission/fluorescence X-ray intensity continuously. The time resolution depends on the sweep speed of monochromator and the flux of X-ray. The fastest time-resolution of QXAFS in SPring-8 is 800 μs/spectrum which using galvano motor driven monochromator and very compact Si channel-cut crystal without cooling system.

Energy Dispersive XAFS (DXAFS)
DXAFS is a method of measuring the XAFS spectrum by one-shot acquisition. DXAFS measurement is done by converting the energy of X rays into position information using a polychromator and monitoring the position and intensity using a position sensitive detector. So DXAFS has higher time-resolution than QXAFS and the time-resolution is about few ms as usual.

Pump-probe XAFS
Pump-probe XAFS is a method that uses bunch structures of synchrotron radiation. X-ray from the synchrotron facility has a time width. For example at SPring-8, the time width of each X-ray is about 50ps and interval between each X-ray is about 100nsec. Pump-probe XAFS use such time-structure and achieve high time-resolution. However, this method can only apply for repeated reactions.