User experiment transient grating, Cris Svetina. (LTP)

• Used 7.11 keV from ACC with very good performance, above 4 mJ.
• Collected pump-probe data on user sample most of the time today
• FXE will operate in 24h mode for the rest of the delivery week

User experiment transient grating, Cris Svetina. (LTP)

• Used 7.11 keV from ACC with very good performance, above 4 mJ.
• Collected pump-probe data on user sample most of the time today, only minor interruptions due to accelerator outages
• After the outage at 21h, SASE came back with 17 eV lower photon energy, so we had to re-calibrate the undulator spectrum
• FXE will operate in 24h mode for the rest of the delivery week

X-ray delivery
- 9.3 keV, >3 mJ/pulse, beam down around 30min

Optical laser delivery
- 800nm PP laser for jet illumination, stable delivery

Achievements/Observations
- Collected a lot of data (from midnight to 6am) with different sample concentrations and mixing delays with the users

User experiment transient grating, Cris Svetina. (LTP)

• Used 7.12 keV from ACC with very good performance, above 4 mJ.
• Collected pump-probe data on user sample
• Sudden timing jump of around 20 ps. Could not find out why this happened some time between 9h today and 18h.
• Needed to add camera to DAQ. Solved this on instrument side using the DAQ assistant. Great tool!

X-ray delivery
- 9.3 keV, >3 mJ/pulse, stable delivery 

Optical laser delivery
- 800nm PP laser for jet illumination, stable delivery

Achievements/Observations
- Optimised hexapod position for SFX
- Collected granulovirus data for geometry calibration
- Started user sample delivery but clogged the nozzle a few times

Preparation for user experiment transient grating, Cris Svetina

• Used 7.12 keV from ACC with very good performance, above 4 mJ
• Got spatiotemporal overlap with transient gratings using monochromatic beam
• One issue solved by DOC: Picomotors could not be scanned in karabacon, even though this worked well two/three weeks ago

BKR called PRC around 06:10AM to inform on vacuum issues at SA1 beamline leading to a lost beam permission for the North Branch.

VAC-OCD found an ion pump in the PBLM / XTD9 XGM presented a spike in pressure that triggered valves in the section to close.

After reopening valves the beam permission was restored; further investigations and monitoring in coming days will continue. Currently all systems work normally.

https://in.xfel.eu/elog/Vacuum-OCD/252

11:15 SASE1/SPB called that they observed and issue with the SASE1 XGM/XTD2: about every 35 seconds the power reading jumps from 4 Watts to zero and back. It seems to be related to some automated re-scaling of the Keithlyes, which coincides. The fast signal and downstream XGMs do not show this behavior. The concern is that this may affect the the data collection later today. 

12:15 The XGM expert was informed via email, however, there is no regular on-call service today. If this cannot be fixed in the next few hours, the PRC advises to use in addition the reading of the downstream XGM for data normalisation. 

13:15 Theo fixed the problem by disabling auto-range. Needs follow-up on Monday, but for this weekend should be ok. 

**X-ray delivery**

- 6 keV, 3.2 mJ/pulse, stable delivery

**Optical laser delivery**

- 800nm PP laser for jet illumination, stable delivery

**Achievements/Observations**

- NKB focus checked and IUT_Slits optimized
- AGIPD quadrants position finalized
- Measured a lot of water BG runs and few runs with Au nanoparticles (sphere with ~50 nm in diameter)

**Issues**

- SideMic data not saved properly (empty array).
- Found relatively high BG when nozzle is IN since the distance in between nozzle tip & the interaction region is ~100um (even 80 um in some cases).
- DA issue (DAQ was stuck in changing) although all the DA looked healthy. DOC fixed the issue (temporarly) together with Egor, Florian, and Steffen.
- Runs callibration were not working

it is not clear why, but the beam position on BIU2 has changed over time, even more since we checked last. it is off in both directions

we see the GATT aperture projection drifting, so it is a change in the beam transport, not in the source.

see the beam, cut by the DIAG1 slit, compared to the cross it should be centred to.

the motor encoders in the beamline have not changed since the beginning, when the beam was pointing correctly.

There are now two watchdogs for the XTD2 attenuator running at the same time

• SA1_XTD2_WATCHDOG/MDL/ATT1_MONITOR020
• SA1_XTD2_OPTICS_PROTECTION/MDL/ATT1

that are configured differently, which results in different pulse limits (see attachment).

X-ray delivery

6 keV, 2.4 mJ/pulse, stable delivery

Optical laser delivery

800nm PP laser, stable delivery

Achievements/Observations

NKB focus cslits optimized
Some progress with AGIPD background although we still need to improve
Catcher and injector motors (X, Z) are aligned well; with defroster, had under 5mm offset in X
Managed to get a jet and overlap with X-rays.

Issues

Beckhoff flowmeters were disconnected and we were not sure which ports to connect, maybe spent 45min to connect to the right ports and restart device.
Helium flow meter was on but not updating, had to restart it too.
Marco noted actual measured flow at beckhoff VS HPLC set flow was perhaps too low, not sure
Vacuum with injector improved, issue was related to nozzle preparation, however even after this fix the chamber pressure was just over the AGIPD interlock. After tuning gas/liquid flow managed to go under it, but possibly this can also be improved.
Often number of pulses was being changed without us requesting it.
One AGIPD module stopped working after moving quadrant.
DAQ data aggregator crashed a few times, Steffan Hauf will look into this issue after we finished the shift.
Could not move one of the AGIPD quadrant (Q4) due to interlock
Background in Q1 and Q3 needs to be optimized, and/or quadrants needs to be moved.

SASE1 bunch number was reduced to 10 pulses for no obvious reason. 

Traced it back to a malfunctioning of the watchdog for the solid attenuator (see attached error message)

Deacttivated the watchdog for SASE1 solid attenuator. Re-activated it again.

Issue: SASE1 (SPB?) was requesting 200 pulses at 6 keV with full power with all solid attenuators in the beam. This was a potentailly dangerous situation for the solid attnenuator (!)

After that the team left to go home. Nobody is available at FXE.  Set pulse number to 1.

Checked status of solid attenuator. Seems that plate 1&2 have some vertical cracks (see attached picture)

X-ray delivery

• 6 keV, 2.6 mJ/pulse, stable delivery

Optical laser delivery

• 800nm PP laser, stable delivery

Achievements/Observations

• NKB focus optimized and PSLITS optimized
• Beam going through IBS camera
• PP laser rough timing checked w.r.t. X-ray
• Catcher and injector motors (X, Z) are aligned well with about 1.5mm offset in X

Issues

• Manifold-MDL issue (reported in Issues tap)
• SPB_IRU_LIQUIDJET/CAM/1 (IRU nozzle insertion camera) is not working. Power cycle required.
• SPB_EHU_Valve closed 2-3 times due to vacuum interlock
• Space (KF50 pipes) in the super-structure was too long for the user injector (nozzle rod). After taking off small spacer, nozzle is very close to the injector valve during insertion. Please check it out whether we can find any better solution or not.

We checked the XTD2 attenuators following the intervention from XRO (compar ewith elog:37, before the intervention).

The wavefront shows similar distortions with the 75 and 150 um as earlier, which is not too surprising since the cracks are vertical.

Attachments 1-5: Beam on SPB_XTD9_SCR with XTD2 attenuator CVDs

Attachments 6-7: Beam on FEL imager with XTD2 75 and 150 um CVDs

• 10 keV beam
• Detector: JUNGFRAU in the burst mode (16 memory cells)
• Achievements:
  • multiple sfx data sets (lysozyme) with 4 and 8 pulses (at 1.1MHz) per exposure taken

The number of bunches during the last night shift kept being changed down to 24 by the device SA1_XTD2_WATCHDOG/MDL/ATT1_MONITOR020 acting on SA1_XTD2_BUNCHPATTERN/MDL/CONFIGURATOR. This was not the case during the previous shifts, even though the pulse energy was comparable. Looking at the history of SA1_XTD2_WATCHDOG/MDL/ATT1_MONITOR020, it looks like this device was started at 16:26:25 on Friday, 1st March.

-Machine status

the cold compressor failure occurred at ~16.30hr today. And it will take around 35 hr to fix it. I will update via email (local contacts for experiments) and Operation Elog tomorrow with more details.

Naresh