User Call

The fifth call for user proposals for the Maloja instrument at the soft X-ray branch Athos is now open until September 15th 2023. General information about the SwissFEL call can be found here: https://www.psi.ch/en/swissfel/calls. The Athos branch as well as the experimental station are still in the commissioning and build-out phase. Therefore, only a limited selection of beam parameters and instrumentation will be available for this call.

For questions and further information about Maloja contact: Dr. Kirsten Schnorr

Standard SASE:

• Photon energies and pulse energies for circular polarization (linear polarization  30-40% less) :
  • 350 - 1000eV with more than 2000μJ pulse energy
  • 1000 - 1300eV with more than 1000μJ pulse energy
  • 1300 - 1600eV with more than 250μJ pulse energy
• Typical bandwidth ≤ 1 %
• Repetition rate 100Hz
• Standard X-ray pulse duration ≤ 100fs FWHM
• Short X-ray pulses with tuneable pulse duration down to factor of x5 relative to standard SASE mode. Pulse energy directly proportional to pulse duration
• Polarization adjustable: Circular +/- (delivers highest pulse energy), linear horizontal, linear vertical
• Energy scan: feasible over +/- 10 % of fundamental energy

Please note, that advanced modes will result in overall reduced machine performance, like lower repetition rate and reduced pulse energy as compared to standard SASE operation. In case you plan to submit a proposal which requires an advanced mode, we advice to consult with the Maloja contact beforehand.

Advanced machine modes with lower operation experience are available on a best effort basis. These include:

Two colour X-ray mode: Two X-ray pulses with independently tuneable photon energies up to 1000eV, maximum delay between the pulses is 500fs and minimum delay is roughly -50fs.

Beam profile:

• Tightest focus reaching 5 μm x 5 μm (FWHM)
• Unfocused beam 3 – 7 mm, depending on photon energy
• Focus adjustable with bendable KB optics to meet experimental requirements   

Optical laser:

• Fundamental wavelength: 800 nm
• Pulse energy 10 mJ
• Pulse duration 35 fs
• Harmonics of the fundamental at 400 nm and 266 nm are available
• TOPAS to provide other wavelengths is under commissioning, if required for your experiment, please consult with the Maloja contact

For this user call, we are able to offer four different setups:

Time-resolved electron spectroscopy

A Specs Phoibos 150 EP hemispherical analyzer is installed for photo- and Auger-electron spectroscopy. A gas needle can be used to inject samples. A grating spectrometer after the interaction point (Scienta XES350) is available for single shot spectral diagnostics.

X-ray absorption spectroscopy with pink beam

A grating spectrometer (Scienta XES350) is installed after the interaction point in transmission geometry. Gaseous samples can be injected using a gas cell and solid samples can be mounted on a high-precision in-vacuum xyz-stage. For transmissive spectral characterization, an electron spectrometer prior to the sample (Specs Phoibos 150 EP) is available.

Single-shot single-particle imaging

A 4M Jungfrau forward-scattering detector is mounted with a detector-to-sample distance of 34cm. For target injection, a pulsed supersonic gas jet (room temperature) or an aerodynamic lens stack injector are available. Optionally, an ion time-of-flight spectrometer can be used in combination with the supersonic jet. Please consult with the Maloja contact in case you plan to use the aerosol injector.

Ion momentum spectroscopy

A COLTRIMS spectrometer with a short or a long ion side is available. For ion coincidence measurements, a hexagonal delay line anode is used, for ion recoil spectroscopy a quadratic delay line anode is available. Gas-phase targets are injected using a supersonic gas jet (Even-Lavie valve, room temperature to 100C heatable). Since the setup is still in the commissioning phase, please consult with Maloja contact for details.