Damage on YAG screen of SA1_XTD2_IMGFEL

A damage spot was detected during the restart of SA1 beam operation at 14h30.

To confirm that it is not something in the beam itself or a damage on another component (graphite filter, attenuators, ...), the scintillator is moved from YAG to another scintillator.

ATT#1: shows the damage spot on the YAG (lower left dark spot, the upper right dark spot is the actual beam). Several attenuators are inserted.
ATT#2: shows the YAG when it is just moved away a bit (while moving to another scintillator, but beam still on YAG): only the beam spot is now seen. Attenuators unchanged.
ATT#3: shows the situation with BN scintillator (and all attenuators removed).

XPD expert will be informed about this new detected damage in order to take care.

SA1 Beckhoff issue

SA1 blocked to max. 2 bunches and SA3 limited to max 29 bunches
At 9h46, SA1 goes down to single bunch. PRC is called because SA3 (SCS) cannot get the required >300 bunches anymore. (at 9h36 SA3 was limited to 29 bunches/train)

FXE, SCS, DOC are informed, DOC and PRC identify that this is a SA1 Beckhoff problem.
Many MDLs in SA1 are red across the board, e.g. SRA, FLT, Mirror motors. Actual hardware state cannot be known and no movement possible.
Therefore, EEE-OCD is called in. They check and identify out-of-order PLC crates of the SASE1 EPS and MOV loops.
Vacuum and VAC PLC seems unaffected. 

EEE-OCD needs access to tunnel XTD2. It could be a fast access if it is only a blown fuse in an EPS crate.
This will however require to decouple the North branch, stop entire beam operation for SA1 and SA3.
Anyhow, SCS confirms to PRC that 29 bunches are not enough for them and FXE also cannot go on with only 1 bunch, effectively it is a downtime for both instruments.

Additional oddity: there is still one pulse per train delivered to SA1 / FXE, but there is no pulse energy in it ! XGM detects one bunch but with <10uJ.
Unclear why, PRC, FXE, and BKR looking into it until EEE will go into the tunnel.

In order not to ground the magnets in XTD2, a person from MPC / DESY has to accompany the EEE-OCD person.
This is organized and they will meet at XHE3 to enter XTD2 from there.

VAC-OCD is also aware and checking their systems and on standby to accompany to the tunnel if required.
For the moment it looks that the SA1 vacuum system and its Beckhoff controls are ok and not affected.

11h22: SA3 beam delivery is stopped.
In preparation of the access the North branch is decoupled. SA2 is not affected, normal operation.

11h45 : Details on SA1 control status. Following (Beckhoff-related) devices are in ERROR:

• SA1_XTD2_VAC/SWITCH/SA1_PNACT_CLOSE and SA1_XTD2_VAC/SWITCH/SA1_PNACT_OPEN (this limits bunch numbers in SA1 and SA3 by EPS interlock)
• SA1_XTD2_MIRR-1/MOTOR/HMTX and HMTY and HMRY, but not HMRX and HMRZ
• SA1_XTD2_MIRR-2/MOTOR/* (all of them)
• SA1_XTD2_FLT/MOTOR/
• SA1_XTD2_IMGTR/SWITCH/*
• SA1_XTD2_PSLIT/TSENS/* but not SA1_XTD2_PSLIT/MOTOR/*
• more ...

12h03 Actual physical access to XTD2 has begun (team entering).

12h25: the EPS loop errors are resolved, FLT, SRA, IMGTR, PNACT all ok. Motors still in error.

12h27: the MOTORs are now also ok.

The root causes and failures will be described in detail by the EEE experts, here only in brief:
Two PLC crates lost communication to the PLC system. Fuses were ok. These crates had to be power cycled locally.
Now the communication is re-established, and the devices on EPS as well as MOV loop have recovered and are out of ERROR.

12h35: PRC and DOC checked the previously affected SA1 devices and all looks good, team is leaving the tunnel.

13h00: Another / still a problem: FLT motor issues (related to EPS). This component is now blocking EPS. EEE and device experts working on it in the control system. They find that they again need to go to the tunnel.

13h40 EEE-OCD is at the SA1 XTD2 rack 1.01 and it smells burnt. Checking fuses and power supplies of the Beckhoff crates.

14h: The SRA motors and FLT are both depending on this Beckhoff control.
EEE decides to remove the defective Beckhoff motor terminal because voltage is still delivered and there is the danger that it will start burning.

We proceed with the help of the colleagues in the tunnel and the device expert to manually move the FLT manipulator to the graphite position,
and looking at the operation plan photon energies it can stay there until the WMP.

At the same time we manually check the SRA slits, the motors are running ok. However, removing that Beckhoff terminal also disables the SRA slits.
It would require a spare controller from the labs, thus we decide in the interest of going back to operation to move on without being able to move the SRA slits.

14h22 Beam is back on. Immediately we test that SA3 can go to 100 bunches - OK. At 14h28 they go to 384 bunches. OK. Handover to SCS team.

14h30 Realignment of SA1 beam. When inserting IMGFEL to check if the SRA slits are clipping the beam or not, it is found after some tests with the beamline attenuators and the other scintillators that there is a damage spot on the YAG ! See next logbook entry and ATT#3. This is not on the graphite filter or on the attenuators or in the beam as we initially suspected.
The OCD colleagues from DESY-MPC and EEE are released.
The SRA slits are not clipping now. The beam is aligned to the handover position by RC/BKR. Beam handover to FXE team around 15h.

Broken Radiation Interlock

Beam was down for all beamlines due to a broken radiation interlock in the SPB/SFX experimental hutch.
The interlock was brocken accidently with the shutter open, see https://in.xfel.eu/elog/OPERATION-2024/203
Beam was down for 42 min (from 3h00 to 3h42) but the machine came back with same perfomrmance.

End of in-house 8496

X-ray delivery

15.13 keV 30 pulses @0.5 MHz and 64 pulses (customized pattern), 0.85-1.0 mJ stable delivery

Achievements/Observations

• We used the customized pattern and it worked well, thanks to everyone involved
• One fuse was blew, TS OCD had to come on site
• Interlock was brocken accidently with the shutter open, which tripped the beam in all SASEs

Broken Bridges

Around 21h20 the XPD group notices that several karabo-to-DOOCS bridges are broken.
The immediate effect is that in DOOCS all XGMs in all beamlines show warnings
(because they don't receive important status informations from karabo anymore, for instance the insertion status of the graphite filters nrequired at this photon energy).

PRC contacts Tim Wilksen / DESY to repair these bridges after PRC check with DOC, who confirmed that on karabo side there were no issues.
Tim finds that ALL bridges are broken down. The root cause is a failing computer that hosts all these bridges, see his logbook entry;
https://ttfinfo.desy.de/XFELelog/show.jsp?dir=/2024/47/22.11_a&pos=2024-11-22T21:47:00
That also explains that HIREX data was no longer available in DOOCS for the accelerator team tuning SA2-HXRSS.

The issue was resolved by Tim and his colleagues at 21h56 and had persisted since 20h27 when that computer crashed (thus 1.5h downtime of the bridges).
Tim will organize with BKR to put a status indicator for this important computer hosting all bridges on a BKR diagnostic panel.

20h16: beam down in all beamlines due to a gun problem
20h50: x-ray beams are back
Shortly later additional 5 min down (20h55 - 21h00) for all beamlines, then the gun issue is solved.

After that, SA1 and SA3 are about back to same performance, but SA2 HXRSS is down from 130 uJ before to 100 uJ after the downtime.
Additionally, MID informs at 21h07 that no X-rays at all arrive to their hutch anymore. Investigation with PRC.

At 21h50, all issues are mostly settled, MID has beam, normal operation continues.
Further HXRSS tuning and preparation for limited range photon energy scanning will happen in the night.

SA2 cell#5 undulator segment moved at ~09:45AM Fri to 25mm without aparent reason and undulator experts need a ZZ to exchange power supply; FEL instensity dropped from 230uJ to 60uJ s consequence.

RCs are preparing south branch for the iminent ZZ. HED is informed.

**Update: ZZ finished by 12:10; recovered performance and re-started delivery by 13:30.

- While FEL IMG with YAG screen was inserted in SA1, EPS/MPS was not limited to the expected 2 bunches, but to 30 bunches; 
- It was found the condition #3 ("SA1_XTD2_VAC/Switch/SA1_PNACT_Close") at the EPS Mode-S was disabled which should be always enabled; 
- Condition #3 has been enabled again and now SA1 is limited to 2 bunches, as expected when YAG screen is inserted. 

Further investigations will be done to find why and when it was disabled. 

Dear MID colleagues, Svitozar (PRC), Bolko and Shan (RCs),
This morning we faced the situation where MID was limited to 400 pulses (mode M) via the EPS signals. The current RF window set at the machine allows to the requested 450 pulses.
The limiting conditions were the inserted graphite filter (#2) and the diamon screen at the MID Pop-in (#17). After a discussion with experts (and thanking Naresh, Wolfgang and Andreas), both conditions in EPS mode F (see attached) are now disabled, as the current SA2 beam offer safe condition for both devices.
This special situation with disabled EPS signals in mode F is in place until Tuesday 05.Nov as MID will stay at ~12.28keV and with HXRSS (500-600uJ). Please note that in case of either a change in photon energy, substantial increase of photon flux, longer SA RF window or the wish to insert YAG screen at the SA2 Pop-in, these two mentioned conditions have to be enabled again at the SA2 EPS Mode F prior these actions take place.
After the beamtime ends on Tuesday 7AM, either me, Naresh or the PRC will make sure these two EPS conditions are re-enabled.
In case of questions please do not hesitate in contacting me.
Best wishes,
Frederik

**Update Mon 15:00: The beamtime delivery to MID is extended up to Tuesday 9AM. At this moment the EPS signals will be enabled again by Frederik W.-F.

X-ray delivery

12.5 keV, ~1.6 mJ

Achievements/Observations:
Collected almost 40 runs of the priority sample with 7 pulses per train using the Polypico injection system.

Issues:
Jungfrau controller issue when changing back to single cell adaptive to collect powder data with new geometry (solved together with DOC).
Pipeline issue after requesting single cell correction - still the same bug in the calibration pipeline, the pipeline has to be re-instantiated after the change.

12.389keV, HXRSS, 1-400+ bunches, 450uJ

• Seeding alignment
• Beamline alignment (Mirror + foccussing)
• Measured energy and moved it the requested value
• Cryos for sample and monochromator are prepared
• Aligned DES spectrometer
• Started with DCCM characterization (440)

This is to report some findings during operation that should be looked into (mostly to avoid in the future, because both negatively affect data quality of the user expt at FXE):

• At the moment, the 99:1 mode affects 4 to 5 pulses out of 100 in SA1, see first screenshot that shows in the top right the IPM reading with each blue point denoting the average pulse energy in a train. This was not always the case. After initial setup on thursday it did affect only a single train out of 100.
• On 27.10., the switching of SA2 between 1 and multiple bunches affected SA1 beam heavily, see the jumps in SA1 pulse energy in the second screenshot shown here:
  • The pulse energy dropped by 15% and
  • the pointing changed vertically by 150 um on the FXE PI (data not shown, but available from karabo trendlines)

Edit 8.11.: Added screenshot (grafana/ctrend) to show that the vertical displacement was permanent (not corrected by the feedback)

X-ray delivery

12.4 keV, ~1.4 mJ

Achievements/Observations

Beam was focused on a YaG, alignment finished up to JF4M

Desy Laser group has fixed the issue about the laser Synchronization.

https://ttfinfo.desy.de/XFELelog/show.jsp?dir=/2024/41/07.10_M&pos=2024-10-07T14:51:12

Naresh

PRC

wk41

14:40hr

FXE and HED reported the laser synchronization issue. Informed to Machine RC. 

LbSync team couldn't fixed this issue remotely and on there way to Schenefeld to fix this issue.

Naresh 

PRC wk 41

X-ray delivery

    6 keV, ~2.8 mJ, continuous beam drift in both direction

Optical laser delivery

    ns laser for particle visualization

Achievements/Observations

    DAta collection for CDI
    Julabo chiller (AGIPD) is still on target (-32 degree)

Issues

    Continuous beam drift in the both direction: NKB focus was optimized almost every 2 hours

01:49

Worked on the XPCS analysis packages
measured the TetraPack samples
continued with the levitation device

issues:

1. Jungfrau detector had an error - R. Shayduk restarted the device - it should be power cycled as described in the manual
2. The bunch number selctor does not work - the system didn't accepted 150 pulse but moved it back to 30 pulses - the machine switched off the user selection - should be followed up tomorrow

**X-ray delivery**

- 6 keV, ~2.8 mJ, continuous beam drift in vertical direction (both XTD2 & XTD9 XGMs)

**Optical laser delivery**
- ns laser for particle visualization

**Achievements/Observations**
- measured sample for almost whole day (about 100 runs x 5 minutes)
- Julabo chiller (AGIPD) is still on target (-32 degree)

**Issues**
- Continuous beam drift in the vertical direction: NKB focus was optimized almost every 2 hours
- Sudden intensity drop in SA1 when SA2 or SA3 changes the number of pulses.

X-ray beam is continuously drifting in the vertical direction (XTD9_XGM)
It affects our NKB focus and focused beam is also drifting continuously.