Connerning the phase shifter adjustment after undulator gap scan via karabo:

At 19:30 FXE tested the scan change via Karabo with BKR. When the energy was changed with step size of 100 eV, the intensity of X-ray stays unchanged. This means the phase shifter adjusment is corrrected and it is working now.

Many thanks for your help.

X-ray delivery

• 7 keV, 2.1 mJ, stable delivery

Optical laser delivery

• None

Achievements/Observations

• M1, M2 pre alignment for this weeks beamtime
• Checked the beam trajectory through MKB mirrors after stripe change

Issues

• It seems that with wider funnel for the catcher, the YAG is not reaching the X-ray beam

Note: At 7 keV with 100 pulses, and full beam we were at 2.2 W average power.

Concerning SASE1:

Please note that for this week the "remote power limit" was set to 5 Watt in order to protect CRL1.
The photon energies this week are 5.5 keV (FXE, day) and up to 7keV (SPB/SFX, night).
Daytime SASE1 operation by FXE will not come close to any damage limits (16 pulses at low rep rate).
However, SPB/SFX will operate at 1.1 MHz and up to 356 pulses/train. If there would be a sequence
procedural error during the shift handover switching of parameters, delivery of 5.5 keV at this rate could damage the CRLs.

If this limit would at any point limit the experiment, please get in contact with the PRC.

• We found that the x-ray pulse energy dropped a lot when we changed the undulator from 5.5 keV to 5.45 keV. We called BKR to optimise it (attachment 1)
  => There is a problem with the phase shifter of the undulator. It stacks sometime. If the x-ray intensity drops, we need to ask BKR to optimise it.
  => We were suggested not to change the undulator value by 100 eV. 5 - 10 eV step should be fine.

On the other hand, we had a user experiment 3435 Feb 2023, and we could perform photon energy scan from 5.7 keV to 6.1 keV without problem. (attachment 2)

Vacuum issue at XTD2 tunnel which might be triggered by SA1_XTD2_ATT Arm5 (1.2mm thick CVD diamond)

It happened once again at around 3pm.

X-ray delivery

• 1.1 mj, 564 kHz, 93 pulses, stable delivery

Optical laser delivery

• 50 fs, 860 nm as fundamental wavelength, 188 kHz
• ns for illumination,

Achievements/Observations

• Lots of data collection for TR-SFX

Issues

• Sample was accumulated on catcher and strong diffraction was observed, need to vent chamber and clean it, but it happned end of beamtime, we decided to finish experiment 

The late shift on the 13th fixed remaining problems with the DLD and the calibration pipeline.

The night shift was then able to collect data on O2 using the two-color mode. Systematic studies were done at different photon energies for both colors. This was done for full FEL intensity and 10%.

The day shift started to investigate if we see an effect changing the delay between the two colors. This turned out to be difficult because we lost the second color when changing the delay. BKR retuned for us with a delay.

Afterward, we asked BKR (Mathias and Mark) to re-tune the two color setup for short pulses.

Upcoming late and night shift should collect more data using the short pulses. Keep in mind to check and record the single pulse FEL spectrum upon each change on the undulator settings.

X-ray delivery

• 1.1 mj, 564 kHz, 93 pulses, stable delivery

Optical laser delivery

• 50 fs, 860 nm as fundamental wavelength, 188 kHz
• ns for illumination,

Achievements/Observations

• Lots of data collection for TR-SFX
• Tried many samples and optimazation

Issues

• Beam fluctuation aorund 23 : 00
• Low hit rate. tried to improve, better than before.

X-ray delivery

• 0.5 mj, improved to 1.1 mj xray energy in the evening

Optical laser delivery

• 50 fs, 860 nm as fundamental wavelength, 188 kHz
• ns for illumination,

Achievements/Observations

• Aligned the instrument to 9.3 keV
• Aligned the PPL laser
• Time zero PPL
• Measured sample, dark runs, including testing different sample conditions (filtered vs not filtered or lower cutoff)
• Measured TR-SFX

Issues

• Low xray energy, BKR improved it afternoon, from 0.5 to 1.1 mj, hopefully we could still get better the following days
• PP-laser AMPHOS issues
• The focus at IRU in the evening had issues, we had to redo the alignment partially. We also had to ask BKR to improve the beam alignment at FEL imager.

Info from Machine RC (Lars):

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Author: Froehlich

One of the cold compressors has stopped working around 2:00 on Saturday morning due to a problem with the new motor (with magnet bearing). Since no beam operation is possible anyhow, the cryo team and machine coordination have decided to start necessary work on cryo plant stages 3&4 already on the weekend, in parallel to troubleshooting the motor problem.

All XFEL shifts up to Monday 7:00 are canceled. The morning shift on Monday will supervise the already scheduled access for the repair of A16 and, if possible, the restart of the linac.

This elogbook entry was sent to following experts:
Photon RC mailing list RC mailing list xfel-operation-board@desy.de

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Direct link to e-logbook entry:
https://ttfinfo.desy.de/XFELelog-sec/show.jsp?dir=/2023/36/09.09_M&pos=2023-09-09T14:51:07

------------------------------------------------------------------------
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- Due to the failure of the cryo cold compressor. The machine is down.

- Next update 9 pm today

Please do watch public display for status info.

Info from MRC (Lars)

-----------------------------------------------------------------------------

The cryo crew reports that the cold compressor that failed is, alas!,
the new one with the magnetic bearing. They have to wait for a colleague
who is not on call to help them with the problem. We expect an update on
their further plans around noon and our status panels have been updated
to reflect that.

Cheers,
Lars

-----------------------------------------------------------------------------

• Data taken from 11 to cryo failure
• Beam conditions stable
• Timing scan for different energy
• Operation stopped after cryo failure
• Cryo jet was heated up then
• Improvements of optical diagnostics (far field monitor)

• Improved the alignment procedure:
  • Using the pin to make sure of the spatial overlap
  • SAXS signal is used to make sure the pin is well centered on the X-ray beam path
  • YAG is only used in combination with ILM to fix with ~5 um precision the height of the beam (moving CRLs on laser focus) and the temporal overlap.
• Recording of the different laser foc planned to be used during the experiment: no aperture, 40 mm, 25 mm, 15 mm diameter

Note:

• Jet failed a couple of time
• We lost the Sync system for 2 hours, got it back again for 30 min, then lost it again

Shift summary 07.09.2023

Achievements:
1. found t0   on LSCO x=0.15 at pre-peak O K edge
2. fluence dependence at dt = 130fs, laser-on-off XAS => laser power at 50%
3. static XAS on the three samples x=0,.15, .4 aorund the pre-peak
4. setting for pump-probe: 1.1 MHz 520 pulses at 100% Transmission, PPL at 50%

Problems: 
10:10pm loss of optical sync on PP laser. realized before starting time-resolved experiments. coarse timing requried !

Program for the night shift:
reestablished timing
resume experimetns, i.e. time-resolved signal on sample (XAS) then start time-resolved RIXS.
 

Achievements:
- Optimized hRIXS settings for OK edge at 145 deg scattering angle, resolution of about 50 meV
- Transferred the user sample
- Prepared for delay scans on fluorescence signal from YBCO

Problems:
- There was no internet connection at XFEL and DESY for some time
- hRIXS camera goes frequently into error
- XRD motors (STY) go frequently into error

Next steps:
- Find time zero on fluoresce signal from YBCO, test the same for the samples
- Test PP laser damage threshold

Achievements

• Determined temporal overlap between the X-ray and laser
• measured Ti L-edge XAS and RIXS on samples for Asamara beamtime

Problems

• No problems

Plan for Next Shift

• Confirm spectrometer resolution at the O K-edge following spectrometer rotation
• Transfer user samples into XRD Chamber
• Check X-ray damage on user samples and begin user program

achievements:

- we found optimum hRIXS settings for 1020 eV but moving the detector arm

- we found optimum hRIXS settings for 920 eV but moving the detector arm, and then grating pitch and detect arm

- energy calbibration for 920 eV

problems:

- lost internect connection around 6 am

- PI-MTE3 camera claims an exposure of 30 sec but in reakity it"d more lik r13 sec.

- if FEL intensity goes to 0 i spikes, the jupyter notebook give errors, referring to objecests ofdifferent sie.

plans:

-

• Received the beam from day shift, aligned to beam stop (low signal due to 4m air scatter, only 700uJ upstream)
  • ZYLA5 camera was having issues, restarted without rotating to limit dropped trains.
  • 1.2mm CVD solid attenuator in SA2 seems to be damaged
• We have trouble with our SEPS interlock after changes last week
  • We are supposed to be able to close the shutter (upstream of CRL3) without removing CRL3 to break hutch interlock, but it still sets bunches to zero. This was raised with DOC, and directly with Mikako who implemented this last week
• We aligned our beam through HED's CRL3
• Establish overlap with Relax laser, and timing on YAG (RF-lock only)
  • Issues with new camera ROI's being too large limiting readout to 3.3Hz
• Start cryojet at 22:00, see if we can squeeze in some laser shots to get signal levels tonight
• Alignment/transmission scans with XFEL planned overnight.

Shift summary for 29th of Aug.

- Conducted Time-resolved Bragg CDI experiment using 3rd harmonic pump laser. 
- Collected coherent diffraction patterns from Perovskite-oxide nanocrystals for various time delay and laser fluence. 
- Checked the correlations between the XGM, diamond detector in SDL, and two Jungfrau detectors running on interleave mode.