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Development of sub-nano second time-resolved XAFS technoque

亚纳米第二次时间分辨XAFS技术的发展

基本信息

批准号：
16205005
负责人：
NOMURA Masaharu
金额：
$ 31.2万
依托单位：
High Energy Accelerator Research Organization
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2007
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16205005/
关键词：
Time-Resolved XAFS Pulsed X-ray Sub-nano Second Fast CCD Detector Heterogeneous Catalysts in-situ structure analysis in-situ electronic state analysis Photo-excited States 水冷型曲率可変結晶湾曲機構

项目摘要

The purpose of this research is to establish the time-resolved XAFS technique with the time resolution ofthe order of sub-nano second in order to perform the structure and electronic-state analyses of the short-lived metal species generated in the course of chemical reactions in solutions and on surfaces. Because the dispersive XAFS (DXAFS) instrument is a unique technique for in-eversible reaction systems, we have developed a fast CCD system to achieve the target time resolution. The timing jitter between the synchrotron X-ray pulse and the master clock of synchrotron ring has been first evaluated and clarified that the jitter of 13.3ps is enough for our time resolution. The fast CCD system has been developed using the TH7888A chip (ATMEL). In this system, the CCD is used as a linear detector (one line) and a memory area (ca. 1000 lines). When the line transfer in the CCD chip is driven with the master clock of synchrotron ring (794 kHz), the generated charges on a detector line is ca … More used by only one X-ray pulse. Because the charges are moved to the memory area by the line transfer of the CCD chip, the stored charges on the memory area conespond to the time-resolved X-ray intensities.The X-ray intensity at the NW2A beam line of PF-AR is too strong to inadiate X-ray directly to the CCD chip, and thus the phosphor (P46) is used to convert the X-ray to visible light and the image of the visible light is reduced using a tapered-fiber plate which is optically coupled with the CCD chip to transfer the visible light to the detector line. A slit system has also been developed to prevent the irradiation of X-ray into the memory area The high power Nd: YAG pulsed laser system (Powerlite 8000) has been introduced to generate the short-lived photo-excited metal species. The timing system between the pump Nd: YAG laser and the probe X-ray pulse has been developed and achieved the sub-nano second time-resolved DXAFS measurement system with the fast CCD.The performance of a newly developed sub-nano second time-resolved DXAFS system with fast CCD has been evaluated at some X-ray energies by measuring the standard samples. The clear characteristics are observed in the XANES spectra, indicating that the developed CCD system woks well as the linear detector for the DXAFS instrument. The XAFS spectra measured with only one X-ray pulse are almost in agreement with that measured using the conventional step-scanning technique. The time course measurements become possible with the time interval (1.26 μs) of succeeding X-ray pulses. We have succeeded in developing the fastest DXAFS instrument in the world. Less

本研究的目的是建立时间分辨的XAFS技术，其时间分辨为亚纳秒量级，用于对溶液和表面化学反应过程中产生的短寿命金属物种进行结构和电子态分析。由于色散XAFS（DXAFS）仪器是一种用于不可逆反应体系的独特技术，我们开发了一种快速CCD系统来实现目标时间分辨率。首次对同步辐射X光脉冲与同步辐射环主钟之间的时间抖动进行了估算，并阐明了13.3ps的抖动足以满足我们的时间分辨率要求。采用ATMEL公司的TH 7888 A芯片研制了高速CCD系统。在这个系统中，CCD被用作线性检测器（一条线）和存储区（约100个像素）。1000行）。在同步辐射环主时钟（794 kHz）驱动CCD芯片行转移时，探测器行上产生的电荷约为 ...更多信息仅用一个X射线脉冲。由于电荷是通过CCD芯片的线转移转移到存储区的，存储区存储的电荷对应于时间分辨的X射线强度，PF-AR的NW 2A束线上的X射线强度太强，不能直接照射到CCD芯片上，并且因此磷光体（P46）用于将X射线转换为可见光，并且使用锥形-光纤板，其与CCD芯片光学耦合以将可见光传输到检测器线。还开发了一种狭缝系统，以防止X射线照射到存储区域。引入了高功率Nd：YAG脉冲激光系统（Powerlite 8000）来产生短寿命的光激发金属物种。研制了泵浦Nd：YAG激光与探测X射线脉冲的定时系统，实现了基于快速CCD的亚纳秒时间分辨DXAFS测量系统，并通过对标准样品的测量，对新研制的基于快速CCD的亚纳秒时间分辨DXAFS系统在某些X射线能量下的性能进行了评价。在XANES谱图中观察到清晰的特征，表明所研制的CCD系统可以作为DXAFS仪器的线性探测器。用一个X射线脉冲测量的XAFS谱与用常规步进扫描技术测量的谱几乎一致。在X射线脉冲间隔为1.26 μs的情况下，时间过程的测量成为可能。我们成功地开发出了世界上最快的DXAFS仪器。少