Shift summary 2024-02-23 07:00 - 2024-02-24 10:00

We got self-seeding at 8.5 keV very quickly after changeover from 10.5 keV operation finished at 2024-02-23 07:00.
Pulse energy ~ 600 uJ. 

Progress is in general good. Most of planned tasks for the day are done.
We called BKR whether we can get a bit more energy/pulse this morning, but it appears difficult. Otherwise, having a bit more energy would be helpful to have enough signal-to-noise ratio for X-ray imaging. 

Achievements: 

• Insert nanofocus lens, pump IC1 sample chamber into vacuum
• Establish X-ray axis, measure source point and divergence
• Set up the CRL scheme overfilling CRL4b nanofocus (the settings used in Feb at 8.2 keV were CRL1 arm 3,5 and CRL2 arm 1)
• Bring the imaging systems to the X-ray axis
• Focus and calibrate the x-ray spectrometers
• Laser-xray timing verified on YAG
• DAMNIT setup 
• Nanofocus imaging optimization (Z-scans) with Cu 25um wire and Siemens star
  • Best focus was identified
• Sample alignment 

X-ray delivery:

stable and flat over 190 pulses per train. 1.1 MHz with ~200 uJ

Optical laser delivery:

NA

Achievements/Observations:

Beam optimization and characterization
Sample injection and data collection for ~10 hours

reasonable hit rates observed but highly fluctuating, making alignment optimisation slow

Issues:
DAQ - restarts needed throughout the shift
Sample injection - copper samples dont give high hit rate and increaseing sample concentration led to clogging
Focus drift - focus was tuned at around 3:30 pm ( from 4 um back to 1.5 um)
-again at 19:30 when we checked again focus was >2microns FWHM returned to 1.5

X-ray delivery: stable and flat over 190 pulses per train. 1.1 MHz with 200 uJ short intervention needed to improve intensity after it dropped

Optical laser delivery: NA

Achievements/Observations:

• Beam optimization and characterization
  - Short pulses tuned and number of spikes reduced
• X-ray focus FWHM calculation found to have a bug in pixel size used
  - rest to 0.2 FWHM of focused beam now better than 1.5 microns
• Laser illumination installed to enable particle visualization to aid alignment and feedback
• Sample injection and data collection for several hours
  - Hits seen from Silver cubes
  - very low hit rate from copper
  - cubes, and spheres

Issues:

• DAQ - multiple crashes and restarts needed throughout the shift
• Proc pipeline - some runs fail to processwhile adjacent runs collected with same conditions (run repeater) process without errors
• Sample injection - copper samples continue to be difficult to inject
  - very low hit rates (few hits seen per run)
  - clogging issues
• Focus drift - focus was tuned at around 3 pm, by 9 when we could check again focus was >3 microns FWHM
• Beam intensity reduced during the shift and BKR needed to tune it back
  - returned intensity to 200 uJ - they asked if we wanted to continue but did not as this could have resulted in more SASE spikes

Beam conditions:

• Used photon energies between 6 and 7 keV, including short undulator scans
• Continuously got 1 mJ despite the short pulse mode that's running
• Bandwidth was found to be 18 eV FWHM at 6.07 keV (0.3%) by monochromator scan against fixed undulator setpoint

Achievements:

• Cr foil scan for energy calibration of the FXE mono
• Prepared setpoints for XAS scans during next week's user expts. at: Ce L3 (5.72 keV), Ce L2 (6.16 keV) and Mn K (6.54 keV)
• IPM calibration against XGMD

Issues:

• ATT MDL (class JJAttenuator) got stuck in INIT state and then did not show that absorber was inserted in the beam path (ticket to be submitted to Ctrls)
• DA3 of FXE DAQ (FXE_DAQ_DATA/DA/3) got stuck in changing state (it got too many parameters inserted). The restart by shutting down the server and waiting for the device to come back up took around 20 mins, see 22.2.2024, 4:24 am to 4:43 am.

X-ray delivery: stable and flat over 250 pulses per train. 1.1 MHz with 400 uJ

Optical laser delivery: NA

Achievements/Observations:

• Beam optimization and characterization
  - Short pulses tuned
  - HIREX setup and used to characterize the number of SASE SPIKES per pulse (~10)

Issues

• 10 SASE spikes per pulse is more than desired
  - discussion with BKR and AccRC regarding possibilities for optimization (feedback in the morning)
  -HIREX data proc is not correct as dark processing fails

  - DOC informed and working on it
  - one issue was gothard II appeard to have timed out - does the number of triggers need increasing?
  -sample jetting setup

  - electrospray working but saw exactly 1 hit in run 32
  - tried to alighn with silver nano-cubes but had to switch to sucrose to increase hit rate to aid alignment
  - no hits with sucrose seen with scanning X +- 1mm

The cross on the FEL imager, which we use as a reference for BKR crew, is not centred on the GATT aperture. when was this changed, and why?

att. 1 and 2 show the current position (the saturated image aids the positioning of the GATT aperture).

att. 3 is from two weeks ago. then, the cross was centred on the GATT aperture.

X-ray delivery

• 1 to ~332 pulses at 6 keV, 4.5 mJ
• Stable delivery
• Number of pulses limited by the Photon Beam Power local limit that is set to 16 W. Is this intentional? All other limits are set to 40 W

Achievements/Observations

• Aligned NKB trajectory
• Achieved NKB focus
• Reduced background scattering on AGIPD
• Started data collection

Issues

• Identified a couple of problems with the new DAQ that we were testing. Controls group informed and investigating

*Achievements :
- Generally rather successful with very high quality beam parameters
- We had a nearly steady 800 uJ+ HXRSS flux during the user run and ~ 4mJ SASE during the setup at HED.
- Beampointing was rather stable throughout the HXRSS operation.
- Users took several shots (>2600 FEL and FEL+ReLAX shots) on target. The beamline setup was very quick prior to that and users were able to get preliminary data to prototype parameters already a day before formal handover to them and could straight go to harvest mode on Saturday morning.  
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* Issues :
- Users still found large Bremsstrahlung fluxes on their background, but this is rather on our side, in conjunction with the users.
- On the last day, we had issues with JF calibrations due to the high run numbers in the proposal. DOC promptly helped out.  
- Initially, we observed fluctuations in the FEL flux. BKR was very prompt to correct for this and user operation was not impacted seriously. Slow drifts in pulse energy were also observed, but again, could be compensated from time to time by them.
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Like after the previous winter maintenance period, the shutter of FXE appears as opened in DOOCS panels even though it is closed (https://in.xfel.eu/elog/OPERATION-2023/58).

shift summary
Andreas, Giuseppe

• continued pumpprobe measurements
• around 5:30 we could not see any image at the MTE3 camera (after sample transfer), we tried to fix it but did not work
• we tried to remove the samples from the LLC, the LLC is vented but the lift cannot be moved, needs to be repaired during the day.

X-ray delivery

• 1-350 at 12.45 keV, 1600 uJ. Stable delivery

Optical laser delivery

• None

Achievements/Observations

• collected data at different delay times 20s and 40s
• we installed new mixing injector to allow for longer delay times; and collected complete dataset with it
• completed four different delay times for the users 14s, 18s, 20s and 40s

Issues

• spent longer times to make stable jet which cause many interruptions and hutch searches almost every 5 mins for several hours.
• it was extremely difficult to mix with delay at 20s with original setup.
• nozzles broken during the day, costing several hours to prepare new ones

X-ray delivery
1-350 at 12.45 keV, 1700 uJ. Stable delivery

Optical laser delivery

None

Achievements/Observations

- collected data at different delay times 14s and 18s with over 7 hours of data collection
- the jet was stabilized again by removing the catcher and decreasing transmission to ~30%
- removing the catcher is critical to get stable jet, that allowed us to run for over 20 runs without stop.

Issues

- The jet was extremely unstable for 1.5 shifts; we needed to stop the runs intermittently with intervals less than 10 mins. 
- It seems difficult in principle to go for longer delay times with the current setting; may be elongating the distance in Y-axis with 400 pixel if the jet stable may help to reach 20s.

Night shift summary
Andreas, Giuseppe

• we finished to measure sample 17 and 41 in CARD 06_Y2018F04
• we transferred sample Card_07_Y2018F19
• we started measuring sample 500 nm Ti #26

Problems:

• the frame could not be grabbed properly from the transfer arm, so we decide to vent and transfer manually
• we realized that FEL beam drifted horizontally, we corrected by moving M2 pitch. (The beam did not move at XGM in XTD10, so it must have been some mirror movement)

X-ray delivery

• 1-350 at 12.45 keV, 1750 uJ. Stable delivery

Optical laser delivery

Achievements/Observations

• completed Uwe and Petra data.
• the jet is almost established for <mixing experiments

Issues

X-ray delivery

• 1-350 at 12.45 keV, 1700 uJ. Stable delivery

Optical laser delivery

• None

Achievements/Observations

• collected about over 15 hours of quality data from different samples (thanks to FXE) with extremely stable jet.

Issues

• Issue with data processing in the morning and from the day before due to DAQ; only half of the detector data were calibrated; this was solved by switching to the old DAQ

X-ray delivery

• 1-350 at 12.45 keV, 1700 uJ. Stable delivery

Optical laser delivery

• None

Achievements/Observations

• fixing many issues with the cube and helium leaks
• collected many quality diffraction data for both jet with and without samples
• data on Nendu mutant (~2.5 hours of data collection) with two different conditions

Issues

• AGIPD data aggregator stopped responding and it took about 1 h to be fixed by DOC, which interrupted the data collection

• some strange streak diffraction appears on JF4M and this has to be removed by scanning X- and Y- nozzle motors carefully

Late shift 07.02.24
Laurent, Martin

Continued with laser preparation

• optimized SHG
• changed lens to f = 600 mm
• knife edge scans
• found optimum lens position (95 mm) for w0 = 70 um
• fluence characterization --> up to more than 2 J /cm^2
• Coarse timing
• Fine timing

night shift summary 07.02.24

Andreas, Giuseppe

program was to determine horizontal an vertical beam size and then create some single laser shot patterns to determine fluence settings for LIPSS.

PROBLEMS:

• knife edge insensitive to beam sizes smaller than 20um due the large beam jitter of the FEL.
• moved to the camera and curved gratings but then encountered vacuum issue with scroll pump down since noon 07.02. fixed by replacing scroll pump.
• useful camera data could not extracted as we cannot control the TPI shutter and have multiple exposures of the camera. STPulser Macro need to be fixed.
• SCS_XTD10_TPI/DCTRL/SHUTTER in the SCS topic is not found after shutting device down when tracking down device issues.

check of the optimized focussing options at 10 keV using only one arm in CRL2 - results still to be evaluated
successful check of the mirror chamber in the experiment hutch of MID - it was possible to reflect the direct beam down and use it under a shallow angle on the sample position