On 29.01 evening the SA3 pre-absorber was interlocked due to M5 mirror.

With the help of Maurizio V., it was found the M5 RY motor has to be driven to 400um position to release the interlock condition and permit beam to SXP and SQS. This relates to a limit switch which was in a undesired location and about 1mm out of position.

A ZZ is organized to happen now, 31.01 at ~12:40, in order to reset a cabinet belonging to one of the Apple-X undulators.

This is agreed with North Branch instruments and RC/BKR.

**Update 13:25: ZZ was successful; SA1 and SA3 beams restored at 13:25

Saturday 01.Feb around 2AM machine went down due to problems with cold magnet at A20:

https://ttfinfo.desy.de/elog/XMLlist?file=/XFELelog/data/2025/05/31.01_n/2025-02-01T07:06:16-04.xml&xsl=/elogbook/xsl/elog.xsl&picture=true

During the early morning BKR used a diffrent trajectory at LINAC to continue lasing, altough with poor performance.

A Desy expert was found (voluntary basis) to made a second ZZ in the morning between 10:30 and 12:30 which fixed the faulty relay for the quadrupole/cold magnet quench system.

Beam was restored to FXE, HED and SQS instruments at ~14:00, including the change of photon energies in SA1 and SA2 as well as pointing corrections and necessary fine tuning.

Due to issues SCS has with pulses from SASE1 lasing in SASE3 and destroying, or at least modifying, their sample, it was decided to change the order in the RF configuration to have SASE3 pulses before SASE1. The change will be done at 12 pm, agreed with FXE.
The impact for SPB will be the loss a few pulses (5%), I contacted Richard to get confirmation that this is ok for SPB.

Best regards,
Martin (PRC week 9)

MID called and reported issue with Dachs terminals at the user labs (probably no power). TS was informed. Because the lab are currently accessible (doors are locked open), TS will take care about it on Monday.

7:20 FXE reports a problem with laser synchronisation (yellow warning light and could not change delay). BKR informs the DESY laser sync group. 

7:51 DESY sync group reported that there was a CPU failing about 6 am this morning which led to the yellow warning light. However, synchronisation was very likely all the time ok withing 5-10fs. The CPU was now reset and everything should be wokring now. 

5:49 HED called and they have problems with the Laser Sync signal. A change of laser delay is not possibe. We supsect that it is similar to earlier this week at FXE, where a crash of a sync CPU caused a similar error. BRK is informed and tries to reach somebody from sync Group via email (at 6:35, no OCD phone number available) . If this does not work, we will work with the shifts starting at 7:00 on this (DOC and new BKR crew). 

8:45 (see also DESY elog entries): After several attempts LBsync timing works, at least for now. One problem was that the crate was constantly rebooting by itself. Now it is stable, but error could happen again. In that case, BKR should activate expert via email. 

Attachements: Location of LBsync server status in DOOCS and status of XFELcpuSYNCEXP1-3 for last light

7:15 SPB reports large background from non-lasing SASE3 bunches. BKR is informed.  

7:50 BKR analysed situation. Everything concerning the orbits is OK, so the background is due to the standard spontaneous background (about < 1% level of FEL beam). With SASE3 running currently 255 lasing bunches and SASE1 single bunch the intensities will be on a similar level. Recommendation to SPB to close SRAs from 3 mm to maybe 1.5 mm to reduce background. 

SASE1 pulse energy drops slowly three times

SASE1 XGM detects three times during the morning some slow drop in puls energies from the SASE1 undulator.
The machine cannot find any correlation with any electron diagnostics.
The XGM-measured beam position indicates no beam position drift (which could then by gradual clipping explain the loss in pulse energy).

SASE1 XTD2 attenuator arm issue

On monday 7.4.2025, one of the SASE1 attenuator arms (SA1_XTD2_ATT/PNACT/A9) with a 2mm Silicon attenuator got stuck when inserted
EEE reports in the XO meeting today that DOC / EEE helped to unblock and remove it from the beam
(from the karabo-history, I assume this was on monday between 10h00 and 10h30).
This arm A9 is now blocked/disabled with the attenuator out of beam to prevent this to happen again until this issue is fixed.
To fix the issue for good and to re-enable operation of arm A9, an access to the tunnel XTD2 would be needed.
The group in charge of this beamline component is XRO. So far there is no access request.
CTRL (Wajid) reminds that also the karabo device needs to be blocked / unblocked.

This week, SPB/SFX receive SASE1 beam.
SPB/SFX (Chan Kim and Tomas Popelar) confirm that they can work this week without this attenuator arm,
in particular because they have their own attenuators and will not use the XTD2 attenuators.
Thus, for operations it seems that this access could wait at least until next week tuesday.

SASE3 Apple-X undulator cell 26 issue - SOLVED

During the night, an issue appeared with the SASE3 undulator cell 26 (2nd last Apple-X undulator).
This cell could not be operated and was in status open.
BKR therefore couldn't tune for linear vertical polarization as required by the SASE3 users at SXP.
A ZZ access was discussed and prepared with the experts from the undulator group.

However, they now found a way to repair the issue from remote without access (info from Mikhail Yakopov / undulator group at 10h20).
The issue is solved.

PRC will contact PES spectrometer experts at XPD to tune polarization monitoring with BKR.

• Alignment of KB mirrors: focused beam H150-200nm x V300-350nm. Characterization of focused beam with wire scan.
• Installed ePIX table and ePIX. Thorlabs server is not running, needs to be fixed by controls during the morning shift
• Aligned rotation center of SSRY and put the beam into it. Moved alignment pin down by 10mm and put protecting cover on it.
• Aligned DES spectrometer crystal (using YAG) to 9keV.
• Checked CRL2 focusing with 9keV. Smallest is 9um (with bender adjust).
• Alexey played with Mono further, second reflection not found. Problem found with actuator.
• Tested FF data. Seems to be good.
•  

self-seeding level in SA2 is currently very low (~100 uJ, about 50% in the pedestal), need more information on how to proceed - is there any chance to improve the seeding, or should we consider going to sase operation.

We observed a damage spot on the SA1 FEL imager. It moves with the target holder, but not sure if its damage on the optical mirror or on the target itself.

This issue is not critical, but can become problematic in case one wants to determine beam size or state of optics (ATT or CRLs) upstream.

Preparation for user expt #7944

X-ray delivery

• since pulses (10 Hz) at 9.3 keV, 3 mJ
• Pointing stability 55 um RMS in the horizontal plane on FXE PI, which is lower as compared to earlier values

Achievements/Observations

• Aligned xrays into FXE vacuum/cryo setup
• Performed ice depositions in-situ and characterized by Xray

Handover

• Beam transport to SPB and 11 keV recovered
• We left Hirex inserted during FXE operation, but closed the GH2 shutter. It is still closed.

Issues

• XTD2 crl lens3x motor moving in wrong direction and already past all limits. Created ticket with EEE (no DOC available) #216784. Lens3x is not needed for the ongoing experiment, but the situation is potentially dangerous.

Preparation for user expt #7944

X-ray delivery

• Since pulses (10 Hz) at 9.3 keV, 2.2 mJ
• Again similar low pointing noise

Achievements/Observations

• Confirmed amorphous ice deposition and -removal
• Optimized scattering geometry
• Calibrated detector position

Handover

• Beam transport to SPB and 11 keV recovered by BKR

Preparation for user expt #7944

X-ray delivery

• Single pulses (10 Hz) at 9.3 keV, 2.3 mJ
• Again similar low pointing noise

Achievements/Observations

• Tested different substrates for deposition of ice
• Optimized ice deposition conditions
• Recorded example data to prepare analysis scripts

Handover

• Beam transport to SPB and 11 keV requested from BKR at 6:30h