A portable on‐axis laser‐heating system for near‐90° X‐ray spectroscopy: application to ferropericlase and iron silicide. (13th February 2020) - Spiekermann, Georg
Abstract : A portable laser‐heating system, optimized for synchrotron X‐ray spectroscopy, is presented. Abstract : A portable IR fiber laser‐heating system, optimized for X‐ray emission spectroscopy (XES) and nuclear inelastic scattering (NIS) spectroscopy with signal collection through the radial opening of diamond anvil cells near 90°with respect to the incident X‐ray beam, is presented. The system offers double‐sided on‐axis heating by a single laser source and zero attenuation of incoming X‐rays other than by the high‐pressure environment. A description of the system, which has been tested for pressures above 100 GPa and temperatures up to 3000 K, is given. The XES spectra of laser‐heated Mg0.67 Fe0.33 O demonstrate the potential to map the iron spin state in the pressure–temperature range of the Earth's lower mantle, and the NIS spectra of laser‐heated FeSi give access to the sound velocity of this candidate of a phase inside the Earth's core. This portable system represents one of the few bridges across the gap between laser heating and high‐resolution X‐ray spectroscopies with signal collection near 90°.