MFX Experimental Methods

Femtosecond Crystallography

The ultrashort, high intensity pulses of LCLS have the advantage of allowing in principle damage-free higher resolution measurements of radiation-sensitive samples such as metalloenzymes. A series of crystals can be illuminated by LCLS X-ray pulses and the diffraction patterns recorded. A full 3D set similar to conventional protein crystallography can be assembled from many crystals or many shots on the same large crystal and yield the protein structure. The crystals can be delivered into the MFX beam mounted on a goniometer system (Cohen et al, PNAS (2014)) or using a liquid jet (Weierstall et al, Rev. Sci. Instrum. (2010)), LCP jet (Weierstall et al, Nature Communications (2014)), an electrospinning jet (Sierra et al, Acta Cryst D (2012)) or droplets (Su et al, JSR (2021)).

Small and Wide Angle Scattering

Small angle scattering measurements at atmospheric pressure are possible at MFX, with the femtosecond pump laser enabling time-resolved measurements to study ultrafast dynamics in biological samples (Levantino et al, Nature Comm (2015)).

X-ray Emission Spectroscopy

X-ray emission spectroscopy (XES) is enabled by XES spectrometers in the von-Hamos geometry for a range of transition metal K-edges in the hard X-ray regime. The design of the modular XES spectrometer at MFX allows observation of several metals of interest at once, enabling unique insights into the electronic structures of multi-metal active sites commonly found in metallo-proteins.