X-ray delivery

• 1.3-1.7 mJ, 10.7 keV, 1-100 pulses, stable delivery

Optical laser delivery

• None

Achievements/Observations

• Aligned beam trajectory for 10.7 keV direct beam
• Installation of imaging optics

Issues

• No major issue today.

X-ray delivery

• 1.3-1.7 mJ, 10.7 keV, 1-100 pulses, stable delivery

Optical laser delivery

• None

Achievements/Observations

• Aligned beam trajectory for 10.7 keV direct beam
• Installation of imaging optics

Issues

• Intensity flucutations when SA3 changing number of pulses, it is related to automatic kicker adaptation.
• AGIPD chiller was not working

X-ray delivery

• 1.3-1.7 mJ, 10.7 keV, 1-100 pulses, stable delivery

Optical laser delivery

• None

Achievements/Observations

• Aligned beam trajectory for 10.7 keV direct beam
• Optimized the microscopy table position and references
• Alingment of spectrometer and first and second crystal

Issues

• Intensity flucutations when SA3 changing number of pulses, it is related to automatic kicker adaptation.
• AGIPD preview update speed was slow

X-ray delivery

• 1.3-1.7 mJ, 1-30 pulses, stable delivery

Optical laser delivery

• None

Achievements/Observations

• Aligned beam trajectory for 10.7 keV direct beam
• Optimized the microscopy table position and references
• Initial alignment and test of test of spectrometer crystal

# Shift Summary

Achievements
 - Measured elastic line with 3000 l/mm and 1000 l/mm grating on NiO sample

Problems
- only 50% of trains with jungfrau data in burst mode are saved in the DAQ. Likely an issue with DAQ configuration.
- we couldn't achieve a good focus on the sample and in the spectrometer. Reason unclear.

# Shift Summary

Achievements
 - Found RIXS signal from CuO as well as off-resonant elastic line signals from NiO and CoO
 - Found a potentially optimal exit arm setting and checked theta angle of sample
 - Determined energy calibration

Problems
 - Overall signal levels were quite low of CoO and NiO samples. This meant we had to work with open exit slits. Long scans would be required for optimization at HR conditions
- Interpolation procedure was giving lower signal as compared to direct integration. Algorithm needs to be checked. Analysis with no interpolation and curve correction is available in Software folder LLG/elastic_line_analysis.ipynb

Plan for next shift
- continue with optimization of hRIXS resolution

End of 30 keV study

The machine finished their attemps for 30 keV tuning while using NEPAL injector laser, unfortunately unsuccessful.
They could not obtain lasing, and all the pulse energy shown during the day on the level of about 20 uJ was only background, no lasing (as confirmed with FEL imager).

The machine has now switched to 24 keV, HIREX was extracted, XGMs adapted accordingly. Preabsorber was inserted, and CRL1 lenses all retracted.
SA2 beamline is in a safe state for machine tuning.

The Euler MDL was updated, so that velocities are restored to standard values also after the stop button was hit before motion was finished.

Please be aware that due to the synchronized motion, which is neccessary to keep the beam on the screen, some motors may move for a longer time with very slow speed (main reason - backlash compensation). We are working on a solution with a minimum speed.

!!! Euler calibration values are NOT connected to motor velocities and it is crucial for the functionality of the MDL that these stay as they are !!!

There was a leak in the Solid Attenuator that increased on Saturday morning when SPB moved the arm number 4 (see last entry ID 236).

We were lucky that a balance developed between the leak and the pumping of the ion pumps, so by setting the setpoints of the three most affected ionpumps to 5x10-5 mbar we could survive the weekend and save the beamtime. 

On Monday Maik and I then entered the tunnel to fix the leak. The need of breaking the interlock to bring a dewar and a pumpcart was already discussed on Saturday/Sunday with the PRC (Jan Grünert) and BKR. So Maik and I could enter on Monday afternoon at around 13:20. We found out that the bellow of the arm number 4 is the leaky one which we removed then and put a blind flange. So the XTD 2 solid attenuator has two removed arms now (see photo).

After about half an hour of pumping both ion pumps on the Solid Attenuator were already in the good 10-6 mbar range. We also set back the setpoint of the three pumps P10160I, P10170I and P10180I to the default value 5x10-6 mbar and put the bridge for the end switch on the connector (see picture). The whole work including cleanup in the tunnel could be finished around 19:15 and the tunnel search crew could then set the interlock back.

So the acute problem with the leak could be solved for first now, but there was no time for the activation of the NEC pump. This should be kept in mind for the next shutdown, when we hopefully have spare parts and can anyway replace the arms number 4 and 5. 

We packed the removed actuator and diamond plate in foil and they are next to the radiation protection release box now and waiting for release (see photo). Email was sent to radiation protection officer.

Thanks to Maik for help and a nice working time yesterday and to Michaela for helping us to bring all the things to the XHE3 shaft building! Thanks also to Raul for talking to BKR as PRC and arranging the final tunnel access appointment!

Finally, we're completely back in operation,
and the performance is recovered in all beamlines.

See also ttfinfo, e.g. https://ttfinfo.desy.de/XFELelog/show.jsp?dir=/2023/44/05.11_a&pos=2023-11-05T16:01:25

North branch down : another e-beam magnets problem

RC informs 12h45 that the linac and the south branch are back in operation and performance is as before the issues with the A21 quadrupole.
However, during the access to XTL, additional manget problems occurred in the T4 and SA3 section.
Several magnet power supplies failed several times, MPS is working on this issue.
Additionally the SA3 burn-through radiation safety monitor was triggered which requires an onsite intervention by D3.
The downtime for SA1/SA3 is expected to last at least one hour.

Accelerator down 9h23 - 12h

RC / BKR informs (10am), that due to a quadrupole power supply failure in A21 a tunnel access to XTL is required.
After the XTL intervention finished, BKR started beam in SA2 at 12h09.

However, when sending beam to SA1/3 a new problem occurred with magnets in that branch, which at the moment makes it impossible to deliver beam to SA1/SA3.
The experts are on their way, we will update when there is new information.

• stable SASE beam delivery with 1mJ pulse energy
• we took data for different optical laser excitation fluences and delays
• we changed from the optical lock to the electronic lock to measure also longer delays.

(Temporary) solution for the vacuum incident in SA1

This morning at 7h18 the vacuum interlock of SA1 closed the beamline valves and thus stopped the XFEL beam delivery for SA1 and SA3.
The reason was a real vacuum problem, with vacuum pressure critically rising in the SA1_XTD2_ATT solid attenuator.
Thanks to VAC-OCD and a workaround it was possible to re-establish beam operation SA1/SA3 already by 8h50, but the problem is not fixed !

History data shows that movements of ATT progressively deteriorated the vacuum since FRI 3.11.2023 morning.
At the moment it is stabilized at a high level, but any further significant deterioration of the vacuum level in ATT would make a tunnel intervention unavoidable.

A vacuum work intervention in the tunnel will cause a beam delivery downtime for SA1/SA3 of at least 5 hours
as we know from a similar previous cases(*). This including an extensive XTD2 undulator tunnel search,
which is required because this cannot happen as ZZ but interlock must be broken.

In order to protect the user beamtimes in SA1 (SPB/SFX) and SA3 (SQS),
the following is necessary and agreed by the coordinators (PRC+RC) and VAC:

1) It is not allowed to move ATT until VAC has repaired the leak (PRC has locked the device)
2) VAC group will enter XTD2 after the user beamtimes end on monday, and will work on removing the vacuum leak. This will affect the FD studies scheduled for monday.
3) SPB confirms that they can work in the current (OUT) state of the XTD2 attenuator
4) If FXE (in-house beamtime) cannot work with these same conditions as SPB/SFX (ATT out), then the FXE beamtime is cancelled
5) FXE is requested to contact PRC by phone

Beam down for SASE1/3: SASE1 XTD2 vacuum issue

Vacuum interlock of the SA1 / XTD2 solid attenuator area triggered closing beamline gatevalves.
VAC-OCD is investigating. No beam possible for SA1/SA3 since 7h18.

The vacuum interlock trip is a real vacuum problem. It could be temporarily circumvented to re-establish beam operation in SA1/SA3, BUT IT IS NOT FIXED.
Beam re-established at 8h50.

Currently all attenuators arms are OUT. The vacuum pressure is still high, returned below critical, but any attenuator movement can increase the vacuum pressure from the leak.
Further assessment by VAC in the next hour(s) will decide if a tunnel intervention must happen today or can be delayed until after the weekend.

• Stable delivery of SASE at 18 keV. The intensity dropped slightly from 1mJ to 0.88mJ during the evening, but everything good.
• fixed the laser pulse-on-demand + FSSS scanning macro
• We take some images series of the laser drilling process for different laser fluences
• We started to take first time resolved data

• stable 18 keV SASE delivery
• measurement of siemens star in the morning
• alignment of phase plate for the nano focussing lenses
• testing and debugging of the pulse on demand macro
• holography test measurements and optimization of online analysis
• alignment of user samples

Problems:

• FSSS ScannerX had to be shutdown and initiated quite often
• We lost the output of the pp laser at 22:30. Laser OCD could solve the problem and the laser was back at 23:45.

X-ray delivery

• 19 keV, ~0.9 mJ/pulse, stable delivery

Optical laser delivery

•  no

Achievements/Observations

• Tried many possibilities to fix the jitter issue. We covered everything we could think of, but in the end it was not possible as we could not avoid restricting ourselves from the 0.4s delay required for the ultrasound, making us then suffer from the inter-train jitter.
• Returned to operational experiment setup, eventhough suffering from the jitter issue.

Issues

• High jitter from output of transducer (Ch 2in oscilloscope) could not be solved.
• Turbopumps went off, then we realized multiple power sockets were powerless (F7,8,9,10,11). We connected the turbos to another socket to resume operation, after which the previous sockets were also fixed. We must reconnect the turbos to the typical sockets sometime soon, best expectation to be comming Monday.

Typical delivery status during daytime during the week:

• SA1 at 19 keV : 841 uJ +/- 41 uJ
• SA2 at 18 keV : 990 uJ +/- 80 uJ
• SA3 at 3.0 keV : 2900 uJ +/- 138 uJ

SD for a stable 2 hours long interval, fast XGM train average (INTENSITY.RAW.TRAIN)

• stable delivery of 1mJ SASE at 18keV
• NAFO lens characterization with caustic scan
• successful detector calibration of AGIPD with LaB6 and alignment of Jungfrau to diffraction signal with LaB6
• test of ptychography with 18keV (not successful)
• successful setup of online holography analysis with test measurements