Khalid S, Caliebe W, Siddons P, So I, Clay B, Lenhard T, Hanson J, Wang Q, Frenkel A I, Marinkovic N, Hould N, Ginder-Vogel M, Landrot G L, Sparks D L, Ganjoo A
National Synchrotron Light Source (NSLS), Brookhaven National Laboratory, Upton, New York 11973, USA.
Rev Sci Instrum. 2010 Jan;81(1):015105. doi: 10.1063/1.3276679.
In order to learn about in situ structural changes in materials at subseconds time scale, we have further refined the techniques of quick extended x-ray absorption fine structure (QEXAFS) and quick x-ray absorption near edge structure (XANES) spectroscopies at beamline X18B at the National Synchrotron Light Source. The channel cut Si (111) monochromator oscillation is driven through a tangential arm at 5 Hz, using a cam, dc motor, pulley, and belt system. The rubber belt between the motor and the cam damps the mechanical noise. EXAFS scan taken in 100 ms is comparable to standard data. The angle and the angular range of the monochromator can be changed to collect a full EXAFS or XANES spectrum in the energy range 4.7-40.0 KeV. The data are recorded in ascending and descending order of energy, on the fly, without any loss of beam time. The QEXAFS mechanical system is outside the vacuum system, and therefore changing the mode of operation from conventional to QEXAFS takes only a few minutes. This instrument allows the acquisition of time resolved data in a variety of systems relevant to electrochemical, photochemical, catalytic, materials, and environmental sciences.
为了了解材料在亚秒时间尺度下的原位结构变化，我们进一步改进了在国家同步辐射光源X18B光束线处的快速扩展X射线吸收精细结构（QEXAFS）和快速X射线吸收近边结构（XANES）光谱技术。通道切割硅（111）单色仪振荡通过一个切向臂以5赫兹的频率驱动，使用一个凸轮、直流电机、滑轮和皮带系统。电机和凸轮之间的橡胶带可抑制机械噪声。在100毫秒内采集的扩展X射线吸收精细结构（EXAFS）扫描数据与标准数据相当。单色仪的角度和角度范围可以改变，以在4.7 - 40.0千电子伏特的能量范围内收集完整的扩展X射线吸收精细结构（EXAFS）或X射线吸收近边结构（XANES）光谱。数据在能量上升和下降顺序下实时记录，而不会损失任何束流时间。快速扩展X射线吸收精细结构（QEXAFS）机械系统位于真空系统之外，因此从传统操作模式转换为快速扩展X射线吸收精细结构（QEXAFS）操作模式仅需几分钟。该仪器能够在与电化学、光化学、催化、材料和环境科学相关的各种系统中采集时间分辨数据。
