Development of X-ray Photoacoustic System for Brilliant Synchrotron Radiation and Analysis for New Materials

在国际合作下，美国和日本利用高亮度同步辐射(SR)源进行了新材料分析的X射线光声研究。X射线光声(PA)仪为改进明亮SR的X射线PA装置，将中心细胞面积缩小为5 mm直径。这使得灵敏度得到了提高，然而，本研究所分配的实际束线不是聚焦束型，从而导致灵敏度降低。对于X射线光声测量，光束通量对于获得足够的信号幅度是最重要的。新的试验和发现随着表面覆盖挥发性液体，X射线PA信号显著增加。挥发性液体的引入对X射线PA测量是有价值的，因为它将信号提高到可探测的阈值以上。对X射线区域进行了光热光束偏转研究，观察到了信号的一些差异。进一步的研究正在进行中。光谱研究应用该方法获得了高温超导体(TSC)的光谱。成功地应用了高TSC的光学厚度样品，其光谱显示在CuK边以上的EXAFS。该方法测量过程简单，可用于新材料的分析。比较了日本的SR源和美国的SR源，在每个环的发射度不同的情况下，测量了存储环的硬X射线通量/电流，发现它们非常相似。对于X射线光谱分析来说，获得足够高的X射线通量是最重要的，而低发射度将成为微观研究的重点。

Under international cooperation, X-ray photoacoustic investigation was conducted for new material analysis with highly bright synchrotron radiation (SR) source in US and Japan.1. X-ray photoacoustic (PA) instrumentationIn order to improve the X-ray PA device for bright SR, the central cell area was decreased to be 5mm diameter. This made the sensitivity improved, however, the actual beam line which was allocated for this study is not focused beam type, thus the resulted sensitivity was decreased. For X-ray photoacoustic measurement, the beam flux is most important to get enough signal amplitude.2. New trial and findingX-ray PA signal was dramatically increased with the surface covering volatile liquid. The introduction of volatile liquid is valuable for the X-ray PA measurement because it raises the signal above the threshold for detectability. The photothermal beam deflection study was also tried for X-ray area and some difference of the signal was observed. The further study is under the progress.3. Spectroscopic studiesThis method was applied to get the spectrum of the high temperature superconductor(TSC). Optically thick sample of high TSC was successfully applied and the spectrum showed EXAFS at above Cu K-edge. This method is very simple in measuring procedure and will be very useful for new material analysis.4. Comparison between SR source in Japan and USEven with different emittance of each ring, the flux of hard X-ray/current of storage ring was measured to find it quite similar to each other. For X-ray PA spectroscopy, it is most important to get enough high flux of X-ray and low emittance will become very significant point for the microscopic study.