Development of X-ray Acoustic Spectrometer Using Synchrotron Radiation

我们课题组创新性地利用同步辐射X射线源开发了X射线声学光谱（XAS）装置和方法。1.装置的研制开发了使用驻极体的X射线声学（XA）探测器（XA单元）。 X射线斩波器、第1电离室、该XA室和第2电离室在光学平台上按顺序对准。 XA 单元安装在 X-Z 脉冲台上，以便对样品进行二维扫描以进行成像。该阶段的扫描以及来自锁定放大器和两个皮安表的数据采集由使用 GP-IB bas line 的微型计算机进行调节。最终组装并建立了一个可以自动操作的XAS整体系统。还开发了一种新的光学检测振动膜运动的探测器，我们称之为“光学麦克风”，以提高灵敏度。成功开发了一种采用光热释电传感器的新检测方法——PVDF聚合物薄膜，该方法同样灵敏且可在真空下使用。2.方法学的发展该方法在材料非破坏性次表面评估的能力方面是独一无二的。为此，X射线被调制为半脉冲形状并照射到样品上。发现延迟信号分量源自地下材料。通过X射线束扫描，揭示了表面下材料的分布。我们将此方法称为“半脉冲 XAS 方法”。还开发了使用聚焦 X 射线束的 XA-EXAFS 光谱和 XA 成像，并成功应用于各种模型样品，以发现原子结构分析和材料 3 维无损评估的潜力。

Apparatus and methods for X-ray Acoustic Spectroscopy (XAS) which was innovated by our research group were developed using synchrotron radiation X-ray source.1.Development of ApparatusAn X-ray acoustic (XA) detector (XA cell) using a electret was developed. X-ray chopper, 1st ion chamber, this XA cell and 2nd ion chamber were aligned in sequence on a optical stage. The XA cell was mounted on the X-Z pulse-stage in order to get the 2 dimensional scanning of the sample for imaging. The scanning of this stage and data acquisition from a lock-in amplifier and the two pico-ampere meters were regulated by a microcomputer using GP-IB bas line. A total system for XAS which can be operated automatically was finally assembled and established.A new detector which detects the movement of a vibrating membrane optically, we call "optical microphone" was also developed for more sensitivity. One more new detection method using a photopyroelectric sensor, PVDF polymer film, was successfully developed which is also sensitive and can be used under vacuum.2.Development of MethodologyThis method is unique in the ability of non-destructive sub-surface evaluation of materials. For this purpose, X-ray was modulated in semi-pulse shape and irradiated on to the samples. It was found that the delayed signal components was originated from a sub-surface material. By scanning of X-ray beam, the distribution of materials under the surface was revealed. We call this method as "Semi-Pulse XAS method". XA-EXAFS spectroscopy and XA-imaging using focused X-ray beam were also developed and applied successfully to various model samples to find the potentials for analysis of atomic structure and 3-dimensional non-destructive evaluation of materials.