Table of Content
Calls for Proposals
- The PSI User Office invites user proposals for the first user run at SwissFEL.
- SwissFEL is being continuously developed but the proposals must be based on the parameters outlined below on this page
- After the submission deadline the proposals are evaluated in terms of safety and technical feasibility. Then they are ranked in terms of scientific criteria by the international SwissFEL Proposal Review Committee (PRC). More information about the evaluation procedure is published on Evaluation. The result of this rating is the basis for the beamtime assessment made by SwissFEL.
- The main proposers are informed by email about the result of the ranking and beamtime assessment.
- The annual calendar for the proposal evaluation is as seen below.
Schedule for Calls
In view of the COVID-19 lockdown at SwissFEL and the commissioning of the ATHOS-beamline, we will use our limited resources to run mainly experiments in the second half of 2020 which could not be performed due to the lockdown and some from the in spring selected proposals. Due to the uncertainty about travel restrictions, we are managing a longer reserve-list of proposals based on the selection of the spring call for proposals. Instead of making a selection of new proposals this autumn, the PSD management decided to process the reserve list in the following two periods July-December 2019 and January-June 2021. This gives us enough flexibility to react on the travel constrictions.
Therefore, we will not open a call for proposals for SwissFEL on August 8, 2020. Next call for SwissFEL proposals will be launched on February 8, 2021.
|SwissFEL Call schedule|
Status of SwissFEL
Current achieved parameters (February 7th , 2020)
- photon energy: 1.8-12.4 keV (12.7 keV is also possible)
- typical bandwidth: 0.25% dE/E, larger bandwidth up to 2% also feasible (photon energy dependent)
- typical pulse energies: 200-600 µJ
- repetition rate: single shot - 25Hz (50 Hz possible under certain conditions)
- X-ray pulse duration: 50 - 100 fs fwhm (shorter pulses possible but with a linear decrease in photon flux)
- X-ray-laser arrival-time jitter: ~ 200 fs fwhm
Please note, that due to the early operation phase of the SwissFEL facility, the evolution in 2020 toward advanced parameters is based on best effort. In addition, due to the concurrent buildup of the ATHOS branch, technical feasibility and resource requirements will be strong criteria in the evaluation.
For the new run the Alvra and Bernina endstations are available with the following parameters:
The Alvra end station of SwissFEL specializes in measuring the ultrafast dynamics of photochemical and photobiological systems using a variety of X-ray scattering and spectroscopic techniques. For the Alvra branch, the Alvra Prime chamber and Alvra Flex in-air instruments will be available with the following parameters.
|Photon energy range||2 keV – 12.4 keV, instrument fully commissioned over the full energy range|
|Bandwidth||Monochromatic (Si(111), InSb(111), Si(311)) and pink beam (0.25% of fundamental); larger bandwidths of up to 2% are also possible (photon energy dependent)|
|Environment||Vacuum (down to 5x10-4 mbar ) up to atmospheric pressure (He or N2)|
|Sample delivery||Liquid jet:
LCP injector (50-100 µm)
GDVN operation possible for user-supplied and operated injector
|Detectors and Spectrometers||
|Photon energy range||5 keV – 12.4 keV|
|Beam profile||Focused 100 x 100 µm2 (fwhm) from design
Unfocused beam 1 x 1 mm2 (fwhm) energy dependent
|Bandwidth||Monochromatic (Si(111), InSb(111), Si(311; commissioning 2019) and pink beam (0.25% of fundamental)|
|Sample delivery||Liquid jet:
|Detectors and Spectrometers||
|Alvra experimental laser|
|Fundamental||800 nm, 35 fs (fwhm), 10 mJ (Ti:Sapphire)|
|Harmonics||800/400/266 nm branch available in parallel to OPA|
|OPA conversion||240 nm – 2.5 µm|
|Pulse energy at the sample position||
Measured OPA pulse energies at the sample location vary with wavelength, ranging between 5 to 100 µJ. For specific pump wavelengths please inquire. Pulse durations are expected to be approximately 75 fs fwhm.
Harmonics branch allows for higher pulse energies at 800/400/266 nm with shorter pulse durations achievable. For current status please inquire.
|Focus||50 x 50 – 500 x 500 µm2 (fwhm)|
The Bernina Instrument is designed for studying condensed matter systems by selective excitation and probes, with emphasis on flexible but precise positioning hardware for diffraction on solid state samples. The instrument can interchange large endstations on rails transverse to beam direction. Two configurable endstation platforms are permanently installed, both having a single vertical axis sample rotation:
- X-ray Diffractometer (XRD), equipped with a two circle detector arm,
- General Purpose Station (GPS), with a multi-purpose horizontal 2-theta arm.
Both endstations can be completed with different sample platforms that allow a large range of of specialized sample environment being precisely positioned:
- Six degree of freedom (DOF) heavy load goniometer,
- Two-circle surface diffractometer combination plus hexapod,
- Kappa arm (6 DOF).
An additional 6 DOF robot arm can be used for flexible detector positioning.
For specific high time resolution experiments a temporarily installed timing diagnostics can potentially be combined with the setup after careful planning with the Bernina staff.
|Photon energy range||4 keV – 12.7 keV, 2 – 4 keV available at higher effort|
|Beam profile||Focused 5x5 µm2 (fwhm, measured) to unfocused 1000x1000 µm2 (fwhm, photon energy dependent).|
|Bandwidth||Monochromatic (Si(111) routinely used, InSb(111), Si(311) and pink beam (~0.2% of fundamental, transmissive spectrometer available).|
|Environment||He or ambient atmosphere, platform for user-supplied chambers, N2 and He based cryostream coolers down to ~80 K (tested).|
Solids: single crystals, powders, amorphous systems. Liquid/Gas only with user supplied equipment.
|Detectors and Spectrometer||
|Bernina optical pump laser|
|Primary pump source||800 nm, 35 fs FWHM, 20 mJ (Ti:Sapphire)|
|Secondary pump sources||Wavelength range||Pulse energy / max. Field||Pulse length||Comments|
|240 – 400 nm||10 – 30 uJ (measured)||50 fs (fwhm)|
|400 – 780 nm||150 – 500 uJ||50 fs (fwhm)|
|1 – 2.5 µm||150 – 500 uJ||50 fs (fwhm)|
|2.5 – 15 µm||5 – 30 µJ||250 fs (fwhm)||Pulse length and energy depend highly on wavelength|
|~1 THz single cycle||>300 kV/cm (measured)||—|
|0.5 – 2.5 THz||—||—||Possible but not yet tested|