An approach for the measurement of the bulk temperature of single crystal diamond using an X-ray Free Electron Laser

Abstract

We present a method to determine the bulk temperature of a single crystal diamond sample at an X-Ray free electron laser using inelastic X-ray scattering. The experiment was performed at the high energy density instrument at the European XFEL GmbH, Germany. The technique, based on inelastic X-ray scattering and the principle of detailed balance, was demonstrated to give accurate temperature measurements, within 8% for both room temperature diamond and heated diamond to 500 K. Here, the temperature was increased in a controlled way using a resistive heater to test theoretical predictions of the scaling of the signal with temperature. The method was tested by validating the energy of the phonon modes with previous measurements made at room temperature using inelastic X-ray scattering and neutron scattering techniques. This technique could be used to determine the bulk temperature in transient systems with a temporal resolution of 50 fs and for which accurate measurements of thermodynamic properties are vital to build accurate equation of state and transport models.From the thermal shield of a spacecraft during atmospheric re-entry 1 to the interior of Jovian planets 2 , matter is often found at pressures and temperatures that are at the limits of where conventional condensed matter and plasma physics formalisms are valid 3 . At such extreme conditions, the kinetic energy of the electrons is comparable to the potential energy of interaction between electrons and the nuclei. For these systems, direct and accurate measurements of thermodynamic and transport properties are vital. Extreme states of matter can be produced by dynamic laser-driven compression [4][5][6] and laser heating techniques 7,8 . These methods can excite a material into a transient state of simultaneously high density and temperature, and thereby enable access to previously unexplored regions of phase space. State-of-the-art experiments investigate the properties of materials driven into these conditions by coupling high-energy lasers with suitable probing techniques 9,10 . In particular, X-ray scattering has proven to be a powerful tool for determining the structure and density, and the development of

The High Energy Density Scientific Instrument at the European XFEL

“…As shown in Fig. 18, this is sufficient to resolve inelastic X-ray scattering from phonons in solids, or ion-acoustic waves in plasmas (Wollenweber et al, 2021;Descamps et al, 2020).…”

A history of high-power laser research and development in the United Kingdom

“…Oxford has pushed hard for UK involvement in the European XFEL in Hamburg, Germany [26] . Gianluca Gregori led the first user commissioning experiment on the MEC (Matter in Extreme Conditions) end station in May 2019 [27] . The experimental team are shown in Figure 4 in the MEC end station.…”

Towards a dynamic compression facility at the ESRF

“…Among other facilities of this kind, i.e. MEC at LCLS (Glenzer et al, 2016), BL3-EH5 at SACLA (Inubushi et al, 2020), DCS at APS (Wang et al, 2019) and HED at EuXFEL (Descamps et al, 2020), HPLF-I is the only one dedicated to and optimized for XAS in both the XANES and the EXAFS range. However, XANES of laser-shocked Fe has also been measured at MEC (Harmand et al, 2015), but with limited data quality, mostly due to intrinsic intensity fluctuations of the X-ray beam, leading to the need for averaging over multiple acquisitions.…”