title: Ceramic micro-injection molded nozzles for serial femtosecond crystallography sample delivery.
abstract: Serial femtosecond crystallography (SFX) using X-ray Free-Electron Lasers (XFELs) allows for room temperature protein structure determination without evidence of conventional radiation damage. In this method, a liquid suspension of protein microcrystals can be delivered to the X-ray beam in vacuum as a micro-jet, which replenishes the crystals at a rate that exceeds the current XFEL pulse repetition rate. Gas dynamic virtual nozzles produce the required micrometer-sized streams by the focusing action of a coaxial sheath gas and have been shown to be effective for SFX experiments. Here, we describe the design and characterization of such nozzles assembled from ceramic micro-injection molded outer gas-focusing capillaries. Trends of the emitted jet diameter and jet length as a function of supplied liquid and gas flow rates are measured by a fast imaging system. The observed trends are explained by derived relationships considering choked gas flow and liquid flow conservation. Finally, the performance of these nozzles in a SFX experiment is presented, including an analysis of the observed background.
authors.affiliation: Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron, Notkestraβe 85, 22607 Hamburg, Germany.
authors.forename: K R
authors.initials: KR
authors.lastname: Beyerlein
authors.affiliation: Photon Science, Deutsches Elektronen-Synchrotron, Notkestraβe 85, 22607 Hamburg, Germany.
authors.forename: L
authors.initials: L
authors.lastname: Adriano
authors.affiliation: Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron, Notkestraβe 85, 22607 Hamburg, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Heymann
authors.affiliation: Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron, Notkestraβe 85, 22607 Hamburg, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Kirian
authors.affiliation: Department of Physics, University of Hamburg, Luruper Chaussee 149, 22607 Hamburg, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Knoška
authors.affiliation: Helmholtz-Zentrum Geesthacht, Max-Planck-Straße 1, 21502 Geesthacht, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Wilde
authors.affiliation: Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron, Notkestraβe 85, 22607 Hamburg, Germany.
authors.forename: H N
authors.initials: HN
authors.lastname: Chapman
authors.affiliation: Photon Science, Deutsches Elektronen-Synchrotron, Notkestraβe 85, 22607 Hamburg, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Bajt