Frontiers in Molecular Biosciences (Dec 2022)

Microfluidic liquid sheets as large-area targets for high repetition XFELs

  • David J. Hoffman,
  • Tim B. Van Driel,
  • Thomas Kroll,
  • Christopher J. Crissman,
  • Christopher J. Crissman,
  • Elizabeth S. Ryland,
  • Kacie J. Nelson,
  • Amy A. Cordones,
  • Jake D. Koralek,
  • Daniel P. DePonte

DOI
https://doi.org/10.3389/fmolb.2022.1048932
Journal volume & issue
Vol. 9

Abstract

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The high intensity of X-ray free electron lasers (XFELs) can damage solution-phase samples on every scale, ranging from the molecular or electronic structure of a sample to the macroscopic structure of a liquid microjet. By using a large surface area liquid sheet microjet as a sample target instead of a standard cylindrical microjet, the incident X-ray spot size can be increased such that the incident intensity falls below the damage threshold. This capability is becoming particularly important for high repetition rate XFELs, where destroying a target with each pulse would require prohibitively large volumes of sample. We present here a study of microfluidic liquid sheet dimensions as a function of liquid flow rate. Sheet lengths, widths and thickness gradients are shown for three styles of nozzles fabricated from isotropically etched glass. In-vacuum operation and sample recirculation using these nozzles is demonstrated. The effects of intense XFEL pulses on the structure of a liquid sheet are also briefly examined.

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