SwissFEL Alvra Experimental Station
Alvra specializes in measuring the ultrafast dynamics of photochemical and photobiological systems in solution, suspension, or crystals, using a variety of X-ray scattering and spectroscopic techniques. Alvra consists of two instruments: Alvra Prime and Alvra Flex. Prime is a helium/low vacuum atmosphere chamber designed to perform a range of techniques, including serial femtosecond crystallography (SFX), X-ray scattering (XDS), and X-ray absorption and emission spectroscopy (XAS, XES, and RIXS) over the full SwissFEL hard X-ray photon energy range of 2-13 keV. Flex is a versatile instrument designed to accommodate user experiments with an X-ray spectrometer that can be used for many different types of measurements, including inelastic X-ray scattering (IXS) and high energy resolution off-resonant spectroscopy (HEROS), as well as host user-provided setups. An overview of the Alvra design parameters can be found here and on the SwissFEL facility here. A user laboratory, to support chemistry and biology experiments is also available on-site. The summary of the lab infrastructure and equipment can be found here.
Alvra is currently in full-user operation mode, with both the Prime and Flex instruments commissioned at 100 Hz. A summary of the experimental station parameters follows
Photon energy range | 2 – 13 keV (full SwissFEL Aramis photon energy range) |
Beam profile | Measured focus 20 µm (FWHM) at 2 and 4.5 keV (defocussed beam also possible) |
Measured focus 1.5 µm (FWHM) at 12 keV (defocussed beam also possible) | |
Unfocused beam: 500 µm to 1 mm (FWHM) energy dependent | |
Flexible KB mirrors can also provide an asymmetric focus | |
Bandwidth | SASE 0.25% (pink beam), large bandwith availabe upon request (up to 2%) |
Monochromatic: Si(111), Si(311) and InSb(111) | |
Sample Environment | From vacuum (5 x 10-4 mbar) up to 800 mbar pressure (He or N2) |
Sample delivery systems | Liquid jet for chemistry: |
- Flat jet (100, 200 and 300 µm) with peristaltic pump | |
- Round jet (25-200 µm) with HPLC or syringe pump | |
LCP viscous injector (50-100 µm) | |
GDVN injectors tested in chamber (user provided) | |
Solid samples upon request | |
Detectors and Spectrometers | 16M Jungfrau forward scattering detector at 10 cm distance (<1 Å resolution at 12.4 keV) |
4M Jungfrau forward scattering detector at 10 cm distance (1.5 Å resolution at 12.4 keV) | |
2 x 2 crystal von Hamos dispersive X-ray emission spectrometer (1-12.4 keV) | |
APD and PIPS diodes for x-ray absorption measurements |
Photon energy range | 6 – 13 keV |
Beam profile | Flexible focus from 10 to >100 µm (FWHM) |
Unfocused beam: ~1 x 1 mm2 (FWHM) energy dependent | |
Bandwidth | SASE 0.5% (pink beam) |
Monochromatic: Si(111), Si(311) and InSb(111) | |
Sample Environment | Atmospheric conditions (in-air setup) |
Sample delivery systems | Liquid jet for chemistry: |
- Flat jet (100, 200 and 300 µm) with gear or peristaltic pump | |
- Round jet (20-100 µm) with HPLC pump | |
LCP viscous injector (50-100 µm) | |
Solid samples | |
Detectors and Spectrometers | 3 crystal von Hamos dispersive X-ray emission spectrometer with 1M Jungfrau detector |
Diodes for x-ray absorption measurements |
Primary pump source | 800 nm, 35 fs FWHM, 10 mJ (Ti:Sapphire) |
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Secondary pump sources | 240 nm – 2.5 micron (OPA with additional nonlinear conversion options). At present pulse energies at the sample location for 240-400 nm have been measured in the range of 10-30 µJ. We expect pulse energies of 150-500 µJ between 400 nm and 780 nm; 150-500 µJ between 1 µm and 2.5 µm. Pulse durations are expected to be approximately 50 fs fwhm. |
Timing diagnostics | Alvra currently has two spectral encoding time-tools available, one pre and one post-interaction region. This approach has been demonstrated at several other facilities and works well for experiments that use the full SASE pulses at the full X-ray range of the endstation (2-12 keV) and for monochromatic experiments at the higher x-ray energies (>6 keV). |
News & Scientific Highlights
Repairing genetic damage with sunlight
An international research team at SwissFEL of PSI has discovered how an enzyme repairs DNA damage with the help of sunlight.
Tender X-rays show how one of nature’s strongest bonds breaks
Short flashes of an unusual kind of X-ray light at SwissFEL and SLS bring scientists closer to developing better catalysts to transform the greenhouse gas methane into a less harmful chemical.
Using light to switch drugs on and off
PSI researchers record a molecular film of a cancer drug fitted with a photoswitch. This opens new insights for drug developers.
Contact
Group Leader and Beamline Scientist at Alvra