Poswal Ashwini Kumar, Agrawal Ankur, Poswal Himanshu Kumar, Bhattacharyya Dibyendu, Jha Shambhu Nath, Sahoo Naba Kishore
Atomic and Molecular Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085, India.
High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085, India.
J Synchrotron Radiat. 2016 Nov 1;23(Pt 6):1518-1525. doi: 10.1107/S160057751601362X. Epub 2016 Oct 7.
An innovative scheme to carry out continuous-scan X-ray absorption spectroscopy (XAS) measurements similar to quick-EXAFS mode at the Energy-Scanning EXAFS beamline BL-09 at INDUS-2 synchrotron source (Indore, India), which is generally operated in step-by-step scanning mode, is presented. The continuous XAS mode has been implemented by adopting a continuous-scan scheme of the double-crystal monochromator and on-the-fly measurement of incident and transmitted intensities. This enabled a high signal-to-noise ratio to be maintained and the acquisition time was reduced to a few seconds from tens of minutes or hours. The quality of the spectra (signal-to-noise level, resolution and energy calibration) was checked by measuring and analysing XAS spectra of standard metal foils. To demonstrate the energy range covered in a single scan, a continuous-mode XAS spectrum of copper nickel alloy covering both Cu and Ni K-edges was recorded. The implementation of continuous-scan XAS mode at BL-09 would expand the use of this beamline in in situ time-resolved XAS studies of various important systems of current technological importance. The feasibility of employing this mode of measurement for time-resolved probing of reaction kinetics has been demonstrated by in situ XAS measurement on the growth of Ag nanoparticles from a solution phase.
本文提出了一种创新方案，可在印度印多尔INDUS-2同步辐射源的能量扫描扩展X射线吸收精细结构（EXAFS）光束线BL-09上进行类似于快速EXAFS模式的连续扫描X射线吸收光谱（XAS）测量，该光束线通常以逐步扫描模式运行。连续XAS模式是通过采用双晶单色仪的连续扫描方案以及对入射强度和透射强度进行实时测量来实现的。这使得能够保持高信噪比，采集时间从几十分钟或几小时减少到几秒。通过测量和分析标准金属箔的XAS光谱，检查了光谱的质量（信噪比水平、分辨率和能量校准）。为了展示单次扫描所覆盖的能量范围，记录了覆盖铜和镍K边的铜镍合金的连续模式XAS光谱。在BL-09上实现连续扫描XAS模式将扩大该光束线在当前具有技术重要性的各种重要系统的原位时间分辨XAS研究中的应用。通过对溶液相中银纳米颗粒生长的原位XAS测量，证明了采用这种测量模式对反应动力学进行时间分辨探测的可行性。
