It was possible to align to HED in parasitic mode to seeding tests

mirror horizontal position (coating stripes) was optimized as far as possible under parasitic conditions

vertical motors calibration and EulerMDL calibration still to be done - collimated beam needed for that.

Vertical motors of M3 now calibrated in first iteration and gemetrical neutral calibrated to 0 in motor settings!!!

New HED positions saved in XRO setpoints 'C'

euler calibration not completed for M3

beam: 30 keV / 30 uJ
reduce to single bunch for insertion
put FEL imager in
put DD into beam at X=178 mm
we found the signal
centering the DD by minimising the diffrence signal

Bias voltage = 40 V

when moving Y there seems to be some mechanical bending of the detector holder. The position reached the negative end of the range (approx. -9 mm).
When moving out and in again we could find the beam at:
X= 178.629 (centred)
Y= -3.48 (close to center)
see screenshot

run 29 with DD and IMGFEL
 

The aperture was opened by moving the slits from 2x2 to 4x4 mm

switch to 2 bunches

screenshot

try to center Y position

stop run 29

run 30: approx. 5 min at this position

change FEL-imager ND filter to 0.9 to avoid saturation
run31

take IMGFEL out and switch to 50 bunches
actual X center = 178.44

move left until we loose the signal and scan x from 176.5 to 179.9
y signal changes -> mechanical coupling
run 32

in order to center the Y position we had to move 2 mm down to -5.53

run 33:
move left until we loose the signal and scan x from 176.5 to 179.9
y signal changes

Now the center of y seems to be at -2.88 mm

Image was observed with FEL YAG imager, x movement does not result in a horizontal motion but it is some sort of a diagonal motion

After some movements the y center is now at -5.23 mm

After a new try the y center is at -3.37 mm

Due to the mechanical problem with the Y-position we do the scan with the K-mono chamber X-motor

-----
see elogs from Jan and Tuba

-----

Sascha made an orbit kick with 150 bunches
due to some numerical problem the kick is disturbed (see screenshot)
DD can reproduce the kick trace
take run 40

Sascha altered the orbit again 150 bunches
https://ttfinfo.desy.de/XFELelog/show.jsp?dir=/2022/47/26.11_a&pos=2022-11-26T17:20:00
(see attached graph)
take run 41

set bias from 40 V to 100 V

run 42

Bias set to 40 V again

beam changed to 27 keV

x-calibration scan from 8.3 to 11.7 (K-mono X)
run 43

Bias -> 100 V
run 44 (as before)

Bias -> 20 V
run 45

Suspicion: beam is touching K-mono setup
move K-mono chamber to X=4.6 mm and move DDM X to 173.55
Y again has to be adjusted, is now -3.18

bias set to 40 V

scan K-mono X from 3.1 to 6.1
run 46

bias runs: see Tuba's elog

I started the upstream XGMs in XTD2, XTD1, and XTD10.

Goal: Analyze and quantify the mispositioning of the new 4mm-aperture behind the undulator

Positions in tunnel:

• ABSP4.2422.SA2 = ABSP4.CELL37.SA2 L_z position 2422.558m
• Last closed undulator for this test is cell16 at 2294m (at end of segment) = SR radiation source point
• IMGTR = 2576m (BT=181.1m, PD=582.0m).
• IMGSR = 2586m (BT=191.6m, PD=591.5m).
• IMGFEL = 2637m (BT=242.0m, PD=642,8m).
• Sequence: end-of-cell16 -- ABSP4 -

Measurements:

• IMGTR : dX=15.15-8.25=6.9mm. dY=17-9.8=7.2mm. Aperture shadow mean diameter = 7.1mm
• IMGSR : Aperture shadow mean diameter = ca. 8.5 mm
• IMGFEL : Aperture shadow mean diameter = 9.0 mm.
  The handover cross is at dy = +1.0mm (up) and dx = -2.6mm (left) relative to the apparent center of the aperture shadow.

Comments to the screenshots:

• The handover cross on the IMGFEL cannot be seen simultaneously with the weak SR background because it has the color scaled to high intensity beam.
• The FEL beam spot is almost perfectly centered on the handover cross.

Calculations:

Conclusions:

The 4mm aperture is misplaced by 0.97mm (x) and 0.37mm (y).
It should be moved dx = -0.97mm and dy = 0.37mm, or the FEL has to be made on a different trajectory.

Bunch number control - SA3 FEL imager

As announced today in the XO meeting the SA3 FEL imager has a new feature, see screenshot, encircled:
- In case of danger for the YAG screen the bunches SA3 are set to "0" via the BunchPatternServer (SA3 Main scene).

What to do:
- Choose a different screen, BN or CBor, and again set the number of bunches needed.
- If operation with the YAG screen is wished reduce the pulse energy at the screen.

Further info:
- In general, danger to the YAG screen, even in single bunch operation, is avoided if the GATT is operated at <10% transmission. Observe the screen Watchdogs.
- This feature is installed at the SA3 FEL imager only, after new recent damages.
- Activate the device with "Start", deactivate the control with "Stop Monitoring".

In case of not-correct behaviour inform the PRC (Andreas Galler this week) or me.
This entry is copied to the ttfinfo logbook.

Update for elog 99:

Now Gotthard timing is changed to new setting for 0.5 MHz.

attached screenshot with gothard timing setting

Machine changed from 0.5 MHz to 1.1MHz new screenshot attached2

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

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.

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

SA2 photon beamline

- SRA position were 7 mm x 7 mm, MID reported they see the hallow of beam shadow at MID Popin

- I have closed the SRA to 3.5 mm x 3.5 mm

Rampdown day activities

The main focus is as usual on checking all tunnel components and to identify any potential
issues that could be fixed during the maintenance period which will be starting this wednesday.
Outline time schedule as sent around last week by Maurizio:

• 7:30-11:00: SASE3
• 11:00- end: SASE2
• 13:00-end: SASE1

During the today x-ray rampdown activities, XPD will work mainly from BKR (Jan, Naresh) and SCS hutch (Theo, Joakim).
Communication via zoom-room REMOTE1 or mobile phones.
Naresh is initially supporting Weilun / Gianluca for their study (SA1 and SA2) and will check both HIREXs.
Joakim will work in SA3 on PES + grating spectrometer with support by SCS or SQS colleagues, probably when XRO is finished with SA3 (after 11:00)
Jan will focus on the MCP detectors and imager in all SASE beamlines, in coordination with the XRO activities.

YAG screen
The damaged screen "YAG2" with Al coating had marks and had been exchanged.
The Imager Watchdog now protects the screen - operational for some months i.e. the number of bunches is shut down to zero if the intensity at the screen is too high. In this case, best then is to use the GATT.
Follow the instructions and informations given in the Imager scene.

BN screen
Also the "BN" screen had slight marks and had been exchanged. This screen suffered from accumulated dose over the years but no special protection is foreseen. The imager Watchdog will warn. BN has a high damage threshold for single pulse damage similar to diamond. In contrast to diamond it will not show spurious reflections, like optical light in the beamline or background from SA1 pulses but it has a lower spatial resolution.
Follow the instructions and informations given in the Imager scene.

An XGM has two single-shot detectors, XGMD and HAMP.

The XTD2 XGMD amplifiers are damaged, thus I operate the XTD2 XGM with HAMP, which I usually use at > 18 keV.

In summary, the XTD2 XGM is fully operational, but I do not have a spare detector any more! Thus, a ZZ is organized for Monday 16.10. around 12:00 and Joakim and I will exchange the damaged amplifiers.

End of 30 keV study

The machine finished their attemps for 30 keV tuning while using NEPAL injector laser, unfortunately unsuccessful.
They could not obtain lasing, and all the pulse energy shown during the day on the level of about 20 uJ was only background, no lasing (as confirmed with FEL imager).

The machine has now switched to 24 keV, HIREX was extracted, XGMs adapted accordingly. Preabsorber was inserted, and CRL1 lenses all retracted.
SA2 beamline is in a safe state for machine tuning.

Ramp down activities completed by XPD. References:

• SASE1
  • https://in.xfel.eu/elog/SASE1+technical+commissioning/2204
  • https://in.xfel.eu/elog/SASE1+technical+commissioning/2205
  • https://in.xfel.eu/elog/SASE1+technical+commissioning/2206
• SASE2
  • https://in.xfel.eu/elog/SASE2+technical+commissioning/1206
  • ...until...
  • https://in.xfel.eu/elog/SASE2+technical+commissioning/1209
• SASE3
  • https://in.xfel.eu/elog/SASE3+technical+commissioning/2220
  • https://in.xfel.eu/elog/SASE3+technical+commissioning/2221

The XFEL photon beam was switched off as planned at 19h00 sharp.

Machine is preparing for opening the photon tunnels tomorrow morning and to start the winter maintenance period.

Data for the Horizontal jitter at the HED Pop-In was observed during beam delivery on cw05 (03-05.Feb) and cw07 (14-16.Feb) (see attached pictures). 

We have a similar base jitter in both periods of beam delivery to HED, ranging from a minimum of 50-60um to around 80-100um in both operational weeks.

The SA3 EPS power limit at the Big brother was disabled to allow photon energy scans in SQS (due to Kr resonance at XGM, invalid power values are generated and then beam is blocked);

Action was performed by Lars F. (RC), Michaela Petrich (PRC) and F. Wolff-Fabris (XO) with Accelerator RPO.

It will be activated again on Monday 15.05.

**Update 15.05: the above mentioned rule is activated again at 08:10AM.

Dear all,

After the incidences reported yesterday and the diagnostic remotely done (where we could narrow down the root cause to the edge-welded below at the Linear stage of the arm Nr. 6 - 2.4 mm CVD diamond], we confirmed this as a fact during the schedule access today. Here is a succint summary of what happened.

1. Although planned for 9:00, we could only enter the tunnel past 10:15 due to some issues for the accurate release of the XTD1 tunnel interlock, in such way that the use of the XHE2 elevator could be used.
2. The first action was confirming the first hypothesis. The result of a direct He-leak test shown a leak rate up to 5*10-6 mbar*l/s, which was consistent with the observation from yesterday. No other leak was found.
3. After securing the vacuum integrity of the lateral sections, venting the long sector took some time.
4. We also had some issues with the vacuum connections of the affected actuator, but eventually it could be eventually removed.
5. A first evaluation of the 2.4 mm CVD diamond, no major damage is evident and the chances of reusing are high (at least at first sight).
6. Also, the repair of the leaky part (or better said, its eventual replacement) seems feasible, and would only depend on finding a similar bellow equipment. XRO is working already on this.
7. The vacuum system could be recover relatively fast to an extent where a general leak test could be performed again. No further leaks were found.
8. After the removal of the arm 6, and the reconfiguration of the pneumatic system, we tested several time (in air and in vacuum conditions) that not having the arm 6 wouldn´t block the use of the solid attenuator. Also XRO check/is checking all the possible implications for the "normal" operation of the beamline.
9. At 13:30 we communicated with BKR and later with the PRC to provide feedback on the progress.
10. At 14:15 we confirmed that we were leaving already the tunnel, so the tunnel search could be triggered.
11. Around 14:30, the SA2 vacuum OK signal was released and confirmed by BKR operators.
12. In conclusion, the time envelope  of effective work (4h) was achieved.

At this moment, the sector vacuum level is recovering positively and the average pressure is in the 5*10-8 mbar after 2,5 hours of pumping the the ion pumps, which is a good indication of the overall success.

With best regards,

R. Villanueva & B. Dickert.