InternalSmall Quantum Systems (SQS): Investigation of atoms, ions, molecules and clusters in intense fields and non-linear phenomena
This instrument will investigate processes in atoms, ions, small molecules and clusters occurring under highly intense beams using a variety of spectroscopy techniques. Scientific areas of application are atomic and molecular physics, chemical dynamics, optical phenomena and matter under extreme conditions.
Samples are typically prepared in gaseous form, in jets or beams, or by trapping. While in the TDR-2006 two major different applications (high-resolution spectroscopy & high-flux applications) were described, leading to the request of two SQS instruments, the startup scenario allows for one instrument only. The major difference lies in the usage of a high-resolution monochromator. The current planning foresees to build the instrument without monochromator suitable for high-field applications, non-linear processes and time-resolved pump-probe investigations. Another consequence of the startup scenario is that funds have been limited to providing basic infrastructure for this instrument only.
Reports
Other working group reports on soft X-ray instruments you find on the SCS page.
SQS Workshop 2008
The first SQS workshop took place in Aarhus in November 2008. Visit the workshop page to get more information including the slides of the given presentations.
Mailing list
To subscribe to the mailing list of this experiment station, please use the form at information for the scientific community.
Instrument design
Initial design, TDR-2006 & startup configuration:
- Utilization of particle detection (electrons, ions) and possibly X-ray spectroscopy are prime techniques. Coherent diffraction experiments need prior verification of achievable resolution and signal strength.
- For investigation of non-linear processes in general the maximum obtainable number of photons/pulse and strong focusing (1 µm and smaller) is required.
- X-ray beam will be focused to focal spots of << 1 µm up to 1 µm, 10–20 µm and ∼100 µm.
- It is assumed that the natural bandwidth of FEL radiation (0.2–0.4%) is sufficient for this instrument. The contribution by higher harmonic radiation requires further consideration.
- The X-ray beam requires pulse-by-pulse diagnostics of intensity, position, (spot size), spectrum and pulse arrival. Regular measurement of X-ray wavefront is wishful. This task might be achieved using the beam-fraction transmitted through the sample chamber.
- The startup scenario foresees currently only the installation of basic infrastructure (hutches, gases, liquids, cabling), final beam shaping and some diagnostics for this instrument.
- It is assumed that users will want to bring their own sample chambers and scientific collaborations might plan to permanently install such equipment.
- Samples will be gases, jets, clusters, ion beams or trapped particles. Experiments are done under UHV vacuum conditions (at least background pressure).
- Specific sample preparation schemes can be envisaged, but are outside the scope of the instrument. Additional resources for the development of ion beam or trap instruments, particularly interesting for the SQS station, had been planned initially, but are not included in the startup scenario.
- Pump-probe experiments using optical lasers (few 10 fs, mJ, MHz) are foreseen, but only one laser system will be build. This laser has to serve instruments in the opposite ends of the hall.
- Construction of one X-ray hutch is foreseen for this instrument. In addition a control hutch will be built for operation of the instrument.
Beamline design considerations
- Instrument is located at SASE 3 beamline (designed for <∼500 eV up to 3 keV, providing horizontal linear polarization).
- Instrument is ∼400 m from source point.
- Beamline will be designed for optimized transport of full intensity, time-stabilized X-ray beam. No wavefront distortions that would influence the creation of very small focal spots shall occur.
- Beamline will not feature a high-resolution monochromator, however suppression of higher harmonics needs to be considered.
