Dear all,

we calibrated the mirror vertical motors to their geometrically neutral.

Please be aware that saved values for beamline settings may no longer be valid. This mainly applies to the vertical motor positions, but will have an impact on Tx and Ry values as well.

As starting point, use XRO Optics Setpoints 'C' - this setting was last used to bring beam to SPB

We fine tuned geometry parameters for linear effects on X motion (parallel offset) for all three mirrors.

dTz was corrected for M2 and M3 to -6.5mm (same geometry)

dTz was corrected for M1 to +6mm

for M2 we were able to do a parabola scan Y motion to check for lrTz

lrTz was then corrected to -433mm

correction in the same direction for M3 did not yield better results

Final mirror positions at HED - see picture

Beam is now aligned back to HED for hand-over to Naresh (see picture)

points achieved:

-vibometer measurements on M2 at high energy, 2,1 and 3 mrad setting

-tried again to find beam through pblm grating, but no success

this morning, ZZ was done together with Sylvia Huynh (EEE) to solve softmono pre-mirror motor issue https://redmine.xfel.eu/issues/177392

The issue was solved and also mechanical functionality of the stage was checked.

After ZZ, the beamline remained interlocked. Hutches will be searched and closed tonight to allow final checks on Tuesday

What has happened:
During euler motion calibration of M1, we were driving the vertical motors by a few mm back and forth. At some point, the Rz motor went into error, as we attempted to go further in negative direction. Resetting the axis several times did not solve the problem. The vertical motors were then moved to 0 position. DOC was called and helped to overwrite some parameters that triggered the error.
When resuming the calibration routine, the beam suddenly got lost and the vacuum interlock triggered V0 to close. Vacuum in M1 recovered quickly, but on M2 popIn, only the direct beam could be seen. At this point, the conclusion was that one of the motor connections must have come loose, which caused the vacuum event and removed M1 from the beam.

It was then decided, that we break the interlock, vent the chamber and re-connect the motor if possible.

The situation we found was the following:
-Rz connection lead-screw to bellow was detached
-mirror sitting on the mirror holder
-significant InGa spillage on chamber bottom, window flanges opposite to the mirror AND a lot of drops on the mirror surface

Pictures are attached.

Intervention:
The lead-screw and nut were exchanged. There was significant wear on the bearing plate, connecting the lead-screw to the bellow.
When trying to install the new lead-screw with a spare bearing plate, it was found that apparently the thread on the bellow side was deformed as well, and the spare part did not fit to the thread. Since the old bearing plate was the only possible way to connect the lead-screw to the bellow, it was cleaned, lubricated and re-used. The position was manually adjusted around 0 position (66,7mm protrusion) and the motor connected.

Recommendations:
- since the damaged bearing plate was re-installed, it should be avoided to move Rz. The motor should be permanently interlocked and only operated with absolute care for initial alignment.
- the mirror surface is severely contaminated with InGa, it must be checked if a position with acceptable beam can be found (only to be done by XRO as this needs Rz to be moved)
- the affected bellow has to be exchanged to facilitate replacement of the damaged bearing plate. As this requires the mirror chamber to be opened, this only makes sense in connection with replacement of the mirror + cleaning of the chamber.

EPS issue for Transmissive imager SA1 (OTRC.2615.T9) w.r.t Operation eLog #96

The motor screen positions w.r.t. the EPS switches had been realigned (last Wednesday 8th May), tested today (14th May) and the EPS is again enabled for the different beam modes. All is back to normal.

Concerning damage of the SA1 FEL imager, Operation-2024 eLog #206

The screen position of the YAG screen - when pressing the screen selection button - has been moved by 1 mm so that the damaged area is out of the field of view, see attached screenshots (damage visible under visible light exposure).
The screenshots show the cross-hair, i.e. its nominal beam position and the circular damaged area at its original position of the screen and the new position.

More information on the damage can be found in the damage report, entry #35:
https://docs.xfel.eu/share/page/site/xfelwp74/document-details?nodeRef=workspace://SpacesStore/fd862f30-c6a3-4a5e-9a65-817cbcebb2d9
Also, there is a comment in ttfinfo: https://ttfinfo.desy.de/XFELelog/show.jsp?dir=/2024/47&pos=2024-11-19T09:39:31

840 pulses not possible at SXP due to big brother settings for the EPS Power Limit rule. The minimum pulse energy was assumed to be 6 mJ while the actual pulse XGM reading is 550 uJ.
Solution: The minimum assuemd pulse energy had been lowered from 6 mJ to 2 mJ. This shall be reverted on Tuesday next week.

EPS Interlock change for Mode30:
the 3 HIREX Interlock conditions had been disabled

X-ray delivery

• 12.72 keV, 10Hz, ~1.4 mJ/pulse, some beam drift in the horizontal direction observed (probably mirror related)

Optical laser delivery

• 487 nm ns laser for pump-probe
• 800 nm PP laser for jet illumination, stable delivery

Achievements/Observations

• Collected PP (pump-probe) dataset with 5 us time delay more than 12 hours
• Jet and data collection was stable most of the time

X-ray delivery

8.951 keV, 1.6 mJ

Achievements/Observations

Beam trajectory and focusing established for 8.951 keV
HIREX inserted for energy reference for calibration tomorrow
Temporary beamstop verified position for direct beam.
Mirror tank inserted to beam path

On Shift: TS, FT, CK, AR, PS

X-ray delivery
8.951 keV, 1.6 mJ up to 200 pulses at 0.5 MHz (intesity drops off at end of train)

Achievements/Observations
Beam trajectory and focusing re-established at 8.951 keV
Temporary beamstop verified position for sweeping - confirmed by eric
Beam sweeping in synchronisation with pulse trains observed!
slit window assembly remounted and beam is going through to back of hutch in perparation for optimisation next shft

X-ray delivery
- 7.0 keV, up to 202 pulses at 564 kHz, 1.0 mJ.
- X-ray beam pointing changed at around 18:12 and it affects nano KB focus (from ~200nm to ~1um).

Optical laser delivery
- ns laser for jet illumination

Achievements/Observations
- Detector moved the most upstream position (~1.5 m sample to detector distance)
- BG measurement with water, buffer low salt
- Silver Behenate measurement for geometry file (mostly for detector distance)
- Data collection for different sample (pure) concentrations

**X-ray delivery**

• 7.0 keV, up to 202 pulses at 564 kHz, 1.0 mJ.

**Optical laser delivery**

• ns laser for jet illumination

**Achievements/Observations**

• Data collection completed for all the requested samples from user.

**Issues**

• Run repeater behave once abnormally.  Run repeater started with 30 minutes duration, but the first run (run #238) stopped after 40 seconds and next run (run #239) started.