Sample delivery

A gas needle is available that can provide high-density atomic or molecular targets of gas-phase samples. The needle is mounted on a manipulator, enabling to bring the outlet of the needle as close as possible to the interaction volume.

A doubly skimmed, continuous supersonic molecular beam can deliver cold atoms or molecules to the interaction region. Liquid samples can be placed in a so-called bubbler, at which a carrier gas is applied that carries a diluted target to the interaction region. Currently the system is not heatable, but an upgrade is foreseen. Implementation of a pulsed valve is also under consideration. The design of this source has been inspired by the CAMP end station (Max Planck ASG at CFEL).

COMO user consortium, led by J. Küpper, CFEL

In the Controlled Molecules (COMO) source, a doubly skimmed supersonic molecular beam is coupled with an electrostatic deflector. This makes it possible to select specific states, sizes, or single isomers of polar molecules and clusters. This source is also suitable to separate the target molecules from the carrier gas, and thus efficiently suppresses background signal. It features either an Even-Lavie or an AmSterdam Piezo Valve.

User contribution, T. Möller group, TU Berlin

This source can create rare gas clusters (Ne, Ar, Xe) as well as pure or doped helium nanodroplets. It features either an Even-Lavie or a Parker valve.

User contribution, P. Piseri, University of Milan

A Pulsed Microplasma Cluster Source (PMCS)  produces large clusters from virtually any conductive material including carbon, metals, metal oxides, alloys and other metal compounds. The sample material is inserted in a small cavity in form of a rod. A pulsed solenoid valve periodically injects a high-pressure gas, thus forming a strong jet directed against the target rod. A high voltage pulse is then applied for a few tens of microseconds to the target rod, which produces a very intense discharge that vaporizes it through ion bombardment.

The gas injection also acts as a carrier gas for the suspended particles, bringing them into the interaction region. Depending on the exact extraction conditions, the created clusters consist of a few hundreds to few thousands of atoms. Their size distribution is characterized by a log-normal distribution.

Note that this source is only intended for use in the NQS end station.

With an aerosol injection system, gas-phase samples can be obtained through droplet atomization. The ‘naked’ particles are then focused by an aerodynamic lens. This source is compatible with the XFEL repetition rate and features two different valves: flow focusing with a Gas Dynamic Virtual Nozzle (GVND), or electrostatic focusing with an Electrospray Ionisation Source (ESI). This source is developed in collaboration with Uppsala University (J. Haidu) and the Sample Environment and SPB groups (J. Bielecki) at European XFEL.

Note that this source is only intended for use in the NQS end station.