2. Protein Crystal Screening at SPB/SFX
A specific call for protein crystal screening (PCS) is open at the SPB/SFX instrument that combines sample characterization and injection tests in the laboratories, followed by screening beamtime at the SPB/SFX instrument.
This call predominantly aims for protein crystals, however, can also include non-protein crystals or other diffracting protein samples if in accordance with the PCS standard parameters (see table below).
Nozzles and injection support will be provided by the Sample Environment and Characterization (SEC) group. This call exclusively addresses injection by gas dynamic virtual nozzles (GDVNs) and double-flow focusing nozzles (DFFNs).
For further information, please contact Katerina Dörner (katerina.doerner@xfel.eu) prior to submission.
Standard Parameters for PCS*
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Photon energy
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9.3 keV
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Detector distance
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125 mm (approx. 1.7 Å edge resolution)
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FWHM focus size
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3.5 um
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Sample delivery
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Low viscosity liquid jet (GDVN, DFFN)
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* Minor changes to some of these parameters may occur due to logistics during the user run
PCS proposals, which are to be submitted to a specific call in the user portal UPEX, will be selected after peer review (including feasibility and safety checks).
3. Cross-instrument proposals
Highly targeted experiment proposals for a specific instrument have better chances of success. If, on the advice of our scientists, specific parts of your project should be conducted on different European XFEL instruments, the selection of two instruments is possible in the proposal form. Make sure that the proposal addresses the experiment sessions on both instruments exhaustively. For schedule reasons, the proposal will receive individual IDs on submission and will be reviewed by both instrument proposal review panels concerned. This option should not be used to submit the same experiment to two different instruments in order to increase the chances for beamtime allocation!
4. X-ray beam conditions for the allocation period
The conditions expected for this allocation period are listed below. Nevertheless, case-by-case verification of specific feasibility conditions with the instrument groups is required.
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Photon energy range
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Expected pulse energy**
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SA1
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5–9.3 keV
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2 mJ
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>9.3–14 keV
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1 mJ
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>14–24 keV
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0.5 mJ
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SA2
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5.8–9.3 keV
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2 mJ
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>9.3–12 keV
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1 mJ
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>12–24 keV
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0.5 mJ
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SA3
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0.5–1.5 keV
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5 mJ
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>1.5–2.5 keV
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2 mJ
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>2.5 keV
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0.5 mJ
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Bunch distribution: 350 X-ray pulses per instrument assume equal distribution at 2.25 MHz operation. Higher or smaller numbers for higher/smaller intra-train frequency. Max. 2250 electron bunches within 500 µs are available for distribution to the instruments (4.5 MHz)
** Pulse energy depends on bunch charge, electron energy, and photon energy.
Explanations:
- The above parameters correspond to the standard SASE operation mode.
- The following special modes are available but require more tuning and are less reliable:
- Hard X-ray self-seeding (SA2; 7–14 keV)
- Hard X-ray two-colour w. variable delay (SA2; 6–10 keV; 0–0.5 ps)
- Soft X-ray two-colour w. variable delay (SA3; 500–3000 eV; 0–1 ps)
- Short bunches (< 10 fs FWHM); requires coordinated scheduling as other instruments and available number of bunches might be affected; time-diagnostics is only partially available
- Full trains at instruments with << 10 Hz rep. rates (~ 2250 pulses)
Experiments requesting these special modes should address the development of new techniques and fields and are expected to involve large communities and facility staff. If included in the final schedule, continuous (24 hr) beam delivery would be planned in this case. Since there is a vast range of detailed specifications for these special modes, proposers are requested to contact the corresponding instrument staff in order to clarify requirements.
5. Experiment reports about previous beamtime
Experiment reports are mandatory and must be submitted 3 to 6 months after the end of each experiment. However, Main Proposers and/or Principal Investigators who have received beamtime in the past and who submit new proposals or continuation proposals must provide the experiment reports related to previous proposal(s) via the User Portal to the European XFEL (UPEX) by Friday 24 June 2022. Missing experiment reports may result in withdrawal of new proposals from the review process. Please refer to further instructions on our homepage.
6. Operation during COVID-19 pandemic
At present, it cannot be excluded that the travel restrictions that affected previous user runs and the specific hygiene measures applying to user operation at our facility this year will also influence operational aspects in the first part of 2023.
In the proposal form, you are requested to detail to what degree your proposal would be affected by the persistence of pandemic conditions and what measures could be taken in order to mitigate these consequences, still preserving good chances of success.
In case of doubt, please contact the instrument groups for advice.
7. User pages and funding options
More practical information for users can be found here:
https://www.xfel.eu/users
Travel funding and living subsistence are available for a number of users affiliated with organizations based in the member countries of European XFEL.
Further details are available here:
https://www.xfel.eu/users/user_guide/funded_user_travel
Specific shipping funding options for organizations based in the member countries of European XFEL are available in order to mitigate the impact of COVID-19 travel restrictions.
European XFEL User Office
Email: useroffice@xfel.eu
Phone: +49 (0)40 8998-6937 or -6767