First high‐pressure XAFS results at the bending‐magnet‐based energy‐dispersive XAFS beamline BL‐8 at the Indus‐2 synchrotron facility. (16th June 2020)

• Record Type: Journal Article
• Authors: Lahiri, Debdutta; Dwivedi, Ashutosh; Vasanthi, R.; Jha, S. N.; Garg, Nandini
• Is Part Of: Journal of synchrotron radiation. Volume 27:Part 4(2020)
• Page Start: 988
• Page End: 998
• Publication Date: 2020-06-16
• Subjects: high‐pressure XAFS -- energy‐dispersive XAFS; Synchrotron radiation -- Periodicals; Free electron lasers -- Periodicals; 539.73505
• DOI: 10.1107/S1600577520006098
• Languages: English
• ISSNs: 0909-0495

Abstract

Abstract : This work reports the first successful generation of diamond‐anvil‐cell‐based high‐pressure XANES data for Nb2 O5, in the framework of limited focusing optics at the Indus‐2 synchrotron facility, India. Abstract : The static focusing optics of the existing energy‐dispersive XAFS beamline BL‐8 have been advantageously exploited to initiate diamond anvil cell based high‐pressure XANES experiments at the Indus‐2 synchrotron facility, India. In the framework of the limited photon statistics with the 2.5 GeV bending‐magnet source, limited focusing optics and 4 mm‐thick diamond windows of the sample cell, a (non‐trivial) beamline alignment method for maximizing photon statistics at the sample position has been designed. Key strategies include the selection of a high X‐ray energy edge, the truncation of the smallest achievable focal spot size to target size with a slit and optimization of the horizontal slit position for transmission of the desired energy band. A motor‐scanning program for precise sample centering has been developed. These details are presented with rationalization for every step. With these strategies, Nb K ‐edge XANES spectra for Nb2 O5 under high pressure (0–16.9 GPa) have been generated, reproducing the reported spectra for Nb2 O5 under ambient conditions and high pressure. These first HPXANES results are reported in this paper. The scope of extending good data quality to the EXAFS range in the future is addressed. This work should inspire and guide future high‐pressure XAFS experiments with comparable infrastructure.