Staff: PV, TS, JK + external collaborators 

X-ray delivery:

10 keV, ~ 800 uJ, 128 pulses, tuning was needed for 10 min. 

Optical Laser:

No PP-laser for this week

Achievements / Observations:

Finalized alignment of X-ray setup

Issues:

No major issue today.

**X-ray delivery:**
* 16 keV, ~upto 1 mJ, 160 pulses
**Optical Laser:**
* None
**Achievements / Observations:**
* Alignement
* Recorded first explosions

The image intensifier in the SQS Exit Slit imager had been exchanged on request of SQS, Thomas Baumann.
Model: Hamamatsu MCP C9546-03-Y001 against C9546-01.
The position of the YAG screen on the camera is slightly shifted which may slightly affect the spectral axis, a few pixels vertically, and approximately 15 pixels horizontally.
The image scale by zoom had not been changed, as before 13 µm/pixel.

The SA3 FEL imager is now protected via the Big Brother server, which creates a beam limit on the bunch pattern server if necessary.
contact Andreas Koch, Lars Fröhlich for more details or consult the imager manual, section 2.9:
https://docs.xfel.eu/share/page/site/xfelwp74/document-details?nodeRef=workspace://SpacesStore/1766b430-7c48-4c46-bb2d-1774d69e1246
demonstration 27.1.2025 to Jan Grünert, Harald Sinn, Andreas Galler.

Function: The Big Brother limits the number of pulses in SA3 via a beam limit in case of danger, individually for each screen of the FEL imager, AND only if an imager screen is inserted. The EPS is valid as before.
This means that if the EPS interlock for the FEL imager is enabled (default setting, 2 pulses maximum), the intervention by the Big Brother could reduce pulses to 1 or 0.
The potential limit of the number of pulses for each screen is shown in the FEL imager scene, as before.

Best practice: Use the GATT to limit the pulse energy. Avoid to operate with a strongly saturated image. Use low absorbing ND filters.

eLogs posts to: eLog Operation-2025,  Zulip SASE3_INSTRUMENT_COMMISSIONING, ttfinfo

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

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.

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

7:20 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. 

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. 

1) BKR calls SUN11h20 and informs about issues with the SA1 SRA. Motors in ERROR.

2) Additionally, there was this morning a fire alarm, where in one rack (SASE1 rack 1.1 in XTD2) the gas extinguishing system was triggered, see also https://ttfinfo.desy.de/XFELelog/show.jsp?dir=/2025/03/19.01_M&pos=2025-01-19T10:22:14

PRC investigating.

BEAM STATUS: SA1 is still lasing at 1100 uJ at 9 keV, IMGFEL is inserted and beam visible. XGM and imagers operational.

• All SA1-SRA MOTORS (SA1_XTD2_PSLIT/MOTOR/) in sa1_beckhoff_mov are in ERROR and cannot be reset.
• Same for SA1_XTD2_FLT/MOTOR/TARGET (in ERROR and cannot be reset)
• SA1_XTD2_SRA_SLIT/MDL/MAIN in ERROR
• Same for SA1_XTD9_IMGPII45/MOTOR/NAVITAR_FOCUS and _ZOOM, but these karabo devices can be RESET, however Hardware State remains ERROR. Hardware interlocked.
• Same for SA1_XTD2_PES/SWITCH/G1_OK and G2_OK, but these karabo devices can be RESET, and the Hardware State here is then OFF. Hardware REGION is normal.
• SA1_XTD2_PES/SERIAL/V101256D and SA1_XTD2_PES/VALVE/V101256D in ERROR, can be reset. the STATE = NORMAL.
• Also found in ERROR: SA1_XTD2_WATCHDOG/MDL/STOP2_BKG_IMGFEL (but can be reset, is stopped).
• BeckhoffPlcMonitor SA1_BR_SYS/PLC/MOV_PLCMON in ERROR, can be reset, Hardware state NORMAL.
• SA1_XTD9_MIRR/ACTRL/RZ in ERROR (not the other related motors)
• SA1_XTD2_PSLIT/LVDT/BLADE... all in ERROR, can be reset, then hardware state ON. Hardware error description: "PLC Error: Terminal is not operational"
• SA1_XTD9_MIRR/ASESN/RY and RZ in ERROR, can be reset, then hardware state ON. Hardware error description: "0xc009"
• SA1_BR_SYS/PLC/XFELO_PLCMON in ERROR, can be reset, Hardware state NORMAL.
• SA1_XTD2_DOOCS/CAM/OTRC_2615_T9 (DOOCS-to-karabo bridge for transmissive imager) not instantiated. I instantiate it, there are no issues, works fine.
• Everything OK with SA1 vacuum devices.

Actions for BKR to continue SASE tuning:

1. The IMGFEL image is oversaturated. Changing to BN. The beam is at (13.5mm / 4mm), while the handover cross is at (12.75, 5.22mm). Beam is clipping at the top SRA blade.
2. inserting transmissive imager (YAG). Beam is fully visible and centered at X=1045,Y=1140. Instruction to BKR to use this imager to shift the beam center, and then continue on IMGFEL.

Further actions:

1. Information to DRC (Bruno)
2. He will inform EEE-OCD to look into the issue and see what they might be able to fix without an access. 
3. If they find out an access is required to fix hardware in XTD2, we will request an access (probably not today but MON or TUE). 
4. A redmine ticket of DOC will collect the infos from DRC and EEE-OCD.

A similar issue at SA1 XTD2 rack 1.1 had occurred in November 2024, see https://in.xfel.eu/elog/OPERATION-2024/205

Updates MON morning:

• EEE made the access request and it was scheduled for MON 10am: #215916 - Suspected blown fuse replacement in Rack 1.1
   

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.

Damage on FEL imager was also seen by our morning shift around 7:50am.

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)

The status of the FXE shutter in the Public status display DOOCS panel is incorrect. Here appears as opened, when it is actually closed.

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.

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.