Activities:

• Investigated SAXS scattering instability and found it to come from the pointing variation of the PPL
• Recorded microscope images of the PPL spot of the pBN to quantify the pointing for different spot sizes
• Enlarged the beam and measured pumped SAXS. Results seem better than before.

Problems:

• PPL pointing is not stable enough for consistent pumping effect in the probed area.
• Sample scanner x motor went into error due to interaction with the magnet and had to be coaxed back into operation.
• FEL down with cryo problem.

Activities:

• correctly positioned magnet
• moved detector upstream and found small beamstop
• Recorded SAXS
• Started tr-SAXS

Problems:

• The SAXS images from laser-excited samples showed unexpected variation between different size rings, central point (ie not a ring) and no scattering. 

Shift Summary

1. Collected optical laser-induced dynamics in HfN and STO/SRO samples.
2. Jungfrau detector transferred data without data dropping issue. 

X-ray delivery

• 12.0 keV, 1.3 mJ, 1-168 pulses @ 564 kHz.
• Stable delivery.

Optical laser delivery

• 1030 nm compressed, THG.
• Stable delivery.

Achievements/Observations

• Collected static and TR-SFX data.

Achieved

1. Brought the 800 nm of optical pump laser to the hutch after the intervention. 
2. Found the rough spatial and temporal overlap between the X-ray and pump laser with MID X-ray eye. 
3. Found the sufficient photo-induced effect on the user sample (HfN) with one unpumped X-ray pulse and 12 pumped X-ray pulses. 
4. Installed the lambda/2 wave plate and controlled the optical laser polarisation at the sample surface.
5. Bragg peak analysis via Extrafoam provides an intuitive and prompt result during the measurement, which is very useful for deciding the following procedure of measurement. 
6. A measurement scan for 3D reciprocal mapping has been collected using the Karabacon macro for varying the time delays and omega angles.

Issues

1. The Jungfrau detector dropped approximately 60% of trains in the saved data.

Report

1. The optical pump laser was not able to be brought to the first X-ray pulse. The first unpumped X-ray pulse data is used as a reference, which is useful to this experiment. 

Achievements

• found larger beamstop
• found center of pinhole and bender settings for beam size
• checked jitter of beam on grating, looks like jittering is large, to be further investigated offline
• checked that patterns are working for the night, to be continued by night crew

Problems

• Major problems with scanner Y, as during the previous runs. Reset axis, Reset and adjust the target position to actual position + move to get out of error.
• Problem with bunch pattern (see separate entry in Operations elog)
•  

We report on an issue regarding the bunch pattern: The bunch pattern read by SCS_RR_UTC/MDL/BUNCH_DECODER shows 48 pulses, but we instead use 50 pulses.

Currently, we have a separate RF window and our 1st pulse Id is 2604. We operate at 2.2 MHz, and as required, 50 pulses. See attachment 1.

This means that the last two pulse Ids are 2700 and 2702. However, these values exceed the number of pulses allowed, and the way the bunch pattern is read (SCS_RR_UTC/TSYS/TIMESERVER:outputBunchPattern,
and the middle layer SCS_RR_UTC/MDL/BUNCH_DECODER) cast the array to 2700 values, so that the number of pulses read is 48 instead of actual 50.

We confirm that we indeed have 50 pulses, as seen by the XGM and by photodiode traces showing 50 peaks.

Since our data analysis strongly relies on the bunchpattern table, this is a critical issue.

For now, the users agreed to use 48 pulses instead of 50 pulses to facilitate the data analysis, but this issue should be investigated.

DOC was called, ITDM is aware and helped finding the reason.

edit 20 Apr 2023, 16:26 : redmine ticket https://redmine.xfel.eu/issues/151949

X-ray delivery

• 12.0 keV, 1.3 mJ, 1-168 pulses @ 564 kHz
• Decaying intensity between 1:20 and 2:40, otherwise stable delivery.

Optical laser delivery

• 1030 nm compressed, THG
• Stable delivery

Achievements/Observations

• Optimised PP laser THG conversion efficiency.
• PP laser spatial and temporal overlap with water jet.
• Collected lysozyme diffraction for detector geometry.

Achieved

1. Brought the X-ray to the end of the beamline. 
2. Aligned the goneometer with a pin. 
3. Found the timing of AGIPD at the detector distance of about 3.4 m from the sample.
4. Found the timing of Jungfrau detector in burst mode.
5. Measured the X-ray beam size at the sample position with the X-ray eye for two combinations of CRL 2 (e.g., CRL2 3,4,7 : 14 um x 19 um, CRL2 3,7: 28 um x 34 um ).
6. Collected some x-ray scattering data from the thin film HfN on the Sapphire substrate.
7. Bragg peak analysis via Extraform is running with 16 X-ray pulses per train.
8. The HIREX gave the energy bandwidth of the self-seeding spectrum about 0.71 pixels. 

Issues

1. The rotation motor of MID spectrometer is frequently stuck. The ticket number is #151832
2. The data calibration pipeline of AGIPD sometimes goes into an error state. It could be related to the XGM data. The ticket number is #151837
3. XTD1 attenuator controller and the watchdog device didn’t behave correctly and died in a few minutes. After that, it removed the attenuator itself without any notice. It could have damaged anything very seriously. 
4. The optical pump laser has had some issues with hardware failure (piezo mirror) since 11:25 today.  The laser group fixed the issues, but the system requires some time to be stabilized until tomorrow morning. It might need more time based on the measurement result tomorrow morning. 

Achievements

• knife edge scans of FEL beam, 30 um x 30 um beam size
• aligned beam stop in front of camera
• triggering pattern tested and works, still need to test with laser and XGM

Problems

• Y motor of beam stop doesn't reach the desired up position
  • had to move the entire camera instead
• Once or twice scanner Y got into error during knife edge scan, resetting the target position to the actual position and pressing move helps.
•  

First four pictures: beam line status at beginning of shift - Beam aligned to MID

Idea is to check M2 parasitic motions again on M3 popin. therefore bringing M2 close to 0 with all vertical motors and Tx as much as possible without using beam on the popin.

Adjusting M1 pitch with it

Approch - drive roll and correct rz offest to stay in at the same horizontal position - adjust also ROLL Offset to show 0 in middle position

When ROLL IS DONE continuE with rx and then ty

offset calibration needs iteration. We started the second iteration but could not finish.

Other pictures: documentation of calibration process

shift summary from Saturday 15.04.2023:

Tasks:

- Calibration of Euler MDL

- Vibrometer measurements at M3 using the RY piezo

Beam was aligned to MID popin

we used values stored in MID setpoints 'B' but went there manually, using the EulerMDL

M1 - X value was corrected, as we found the center of the beam/mirror to be at 6.4mm - calculated beam angle after M1 is 2.14mrad

M2 - values slightly differ from saved setpoints but were quite well met using EulerMDL to reach the same beam position

M3 - we had to remove it a bit further from the beam, as it seemed to intercept it, when we first tried to get the beam through. This might in the end not have been necessary

End of shift:

beam aligned to MID

preabsorber in

SRA fully open

Update of the damage tests at SQS.

Yesterday (15.04) SQS staff created a focused beam on our sample using a small YAG fragment we have placed on the holder.

Due to the unusual position, the beam is full of aberrations but it looked small enough for our purpose. Estimattion of the size is difficult atm but it is our intention to measure it with imprints.

We managed to align the sample 1 (silicon, uncoated) in grazing incidence at 19 mrad and found the damage threshold at current focusing conditions at around 100 uJoule (looking on the SQS XGM).

We managed to align also on sample 2 (silicon, B$C coated) at the same grazing angle and we found a threshold at around 200 uJoule.

We started to do systematic spots at various energies, using the GATT

One difficulty is that the manipulator is not enough precise to scan several mms in grazing incidence, the sample has to be realigned along the scan and we cannot find a clear centering on the sample due to the lack of reproducibility.

In the late shift we started to do imprints to characterise the beam spot.

Overall the experiment is on a very good status. Until now, we explored only single pulse damage. Today (16.04) we will try multipulse damage and single pulse damage at 9 mrad.

 

Today we comtinued the program, changing to 9mrad amd 15mrad and doing also multipulse. We had a short interruption at around 15 to extract some samples and to realign Sample 3.

End of Diamond Sensor Study

We leave the SASE2 beamline in the following safe state:

• Pre-Abs inserted
• Solid ATT with T=0.001
• All CRLs OUT
• All imagers OUT

Trigger issue with SXP_XTD10_IMGES - Exit Slit imager

The external trigger of the Navitar camera was not set, fixed now.
The single pulse trigger of the imager: MCP + camera is tested and correctly working.
The pre-settings are stored in Karabo and should come up again, also after Karabo updates.

REPAIRED / FIXED

Problem: The imager SPB_XTD9_IMGPII45 insertion motor lost steps and kept the machine to maximum 2 bunches per train.
Mitigation by DOC/EEE/PRC on 8 April 2023: made sure that screen seems actually out of beam and took imager out of interlock condition.
Repair by XPD on 10 April 2023 02h15: 
a) recalibrated OUT position.
b) verified that EPS-OUT switch shows green when moving to OUT position in MDL.
c) put back the imager into the interlock conditions.
d) communication with BKR before and after the intervention (SPB and FXE didn't use the beam).
Repair instruction see: https://in.xfel.eu/elog/SASE1+technical+commissioning/2065

REPAIRED / FIXED

Problem: The imager SPB_XTD9_IMGPII45 insertion motor lost steps and kept the machine to maximum 2 bunches per train.
Mitigation by DOC/EEE/PRC on 8 April 2023: made sure that screen seems actually out of beam and took imager out of interlock condition.
"Repair" by XPD on 10 April 2023 02h15:
a) recalibrated OUT position.
b) verified that EPS-OUT switch shows green when moving to OUT position in MDL.
c) put back the imager into the interlock conditions.
d) communication with BKR before and after the intervention (SPB and FXE didn't use the beam).
Repair instruction see: https://in.xfel.eu/elog/SASE1+technical+commissioning/2065

9.752 keV, self-seeding, 700-800 uJ.  Intensity is very stable, ponting is also much stable than usual. very good beam.

Beamtime #3326 - Axion search.

Successfully aligned two Ge crystals to Laue conditions (Rocking curve width ~0.002 deg) . Found Laue reflections after 2 crystals on Jungfrau detector.

We realized that the Xeryon rotation stages used for rotation of stage was wrongly calibrated (1 deg was not 1 deg), which caused some confusion. But we found a workaround solution. Still, we doubt about the repeatability and stability of the stage.

The biggest issue was that we lost the Laue reflection very quickly when we put a full intensity onto the crystal. The beam size is about 500 um FWHM. The Bragg angle at the heated sample fluctuate (does not go toward a single value).

We tested several different x-ray intensities to find the optimum flux where the Bragg condition stays. It seems, if we go to 0.1% transmission, the decay time is about 20 - 30min, which may be good enough for data.

We also discussed on swiching back to SASE. As the fluctuation of the Bragg angle seems to be  < 0.02 deg, which would be covered by  the SASE bandwidth. But, that means the photon energy goes to the second crystal fluctuate, then we lose the Laue reflection from the second crystal - probably going to SASE doesn't solve the  issue. This is the current situation.

We called DOC - Optics hutch attenuation stopped working - solved. Jungfrau2 data cannot be taken by DAQ - we decided not to solve this issue as JF2 is not necessary for this beamtime any more.

We notice that 0.5 mm Silicon ATT in SASE1 causes holo beam profile in FEL imager. Maybe this silicon att has been damaged.

Beam delivery for proposal 3378

Achievements/Observations

• Collected large amounts of data for the user program on water crystallisation and angular correlations

To do for next shift:

Continue taking data