Achievements

• Work on laser to improve the beam profile and reduce pointing. Apertured the beam upstream of focusing lens and changed to f=750 mm. Significant improvement.
• Characterized beam size, found positions of photodiode, antenna
• Check coarse timing with reference
• Aligned FEL beam to sample

Problems

• Problems with smaract stages
  • Fixed with the help of DOC (Loic) by power cycling controller after long debugging.
• Beam down just before attempting coarse timing.

achievements

• aligned the beam through up to the XOX imager
• prepared FFT for reflectivity measurement
• tested new DSSC gain files for Tb M5 edge

problems

• in-vacuum piezo motor for the THz parabola stopped working, venting XOX required for troubleshooting, not using the X-ray beam this night

achievements

• try pumping STE membrane with FEL and detect THz emission with single shot EOS. No success.
• tried cross-polarization for a short time, no success either.
• reduced the PPL chirp to record single shot transient reflectivity data versus BAM for the night.

issues

• FEL on STE on sapphire show strong glowing so it's probably not the right regime to get THz
• we don't have a self referencing scheme to observe THz emission from PPL pump

achievements

• checked coarse timing between FEL and PPL at XOX. It had shifted significantly
• determined that light coming out of sapphire from FEL was not heating but fluorescence
• observed for the first time THz emission from STE from FEL pump on sapphire substrate and mesured with single shot EOS

issues

• FEL down for 3h

Achievements

• Optimized THz EOS, managed to observe single shot EOS trace with good SNR
• Characterized chirp with different glass lengths
• Ran SiN spectral encoding in parallel

Issues

• No major issue

achievements:

• hooked up sample cooling and reached 20K at sample at typical low consumption rate
• we archieved targeted resolving power of ~10,000 or 86meV @ 857eV at low temp 20K after indications that heating broadens the elastic line of CoO
• we observe sample damage at 30% and higher transmissions using 350pulses at 1.13MHz, while 20% or less seems fine and elastic line width and intensity remains stable
• we optimise focus condition == 10microns with focus downstream of sample position. KB VFM = 2.04  (beam size vs KB VFM was measured via knife edge scans) dE ~80-85meV
• transfer new sample holder with test sample

plan for tonight and tomorrow morning

• the exit arm may still improve the resolving power, less may be expected from the grating pitch. this can be explored but has lower priority as we reached slightly above E/dE = 10,000 already.
• take RIXS and XAS data on test sample, find optimum settings (damage threshold, camera readout etc) 
• late shift will start with 800nm timing.

problems:

• nothing to report

Achievements

• Two color mode established with 11.5 GeV, 1.335 keV col1, 1.27 keV col2
• Beam size characterized using Viking + online tool
• Jet found by scanning and looking at transmitted signal on Viking

Problems

• Issue with train Id of Chem motors --> fixed by setting proper trigger
• Beam loss around 19:30 induced instability in the two color mode, slow degradation of intensity and stability until 23:00 when it was not possible to use the beam
  • Called PRC, decided to tune to single color, 1.3 keV for the night
• Jet froze

Achievements

• Beam transport
• Coarse and fine timing
• XAS on Co
• Aligned HSLIT, pinhole, camera beamstop
• Characterize FEL beam size and position on curved grating
• PPL Power measurement
• Fluence scan on sample of optical laser and FEL to determine good conditions
• Prepared for night shift time-resolved measurements

Problems

• No major issue

achievements:

1. found new M2 bender position for focusing using blank
2. tried to use unfocused beam for ESLITS calibration, but could not see it at SCSPopin, only at M5 Popin
3. we moved the XRD chamber laterally, closer to hRIXS, to be able to cut the beam using the sample at grazing incidence
4. seen FEL on antenna, measured FEL spectrum at navitar

problems:

• general slowness of SA3 motors whenever the whatchdogs were active, switching them off seems at least to mitigate (solve) the problem
• navitar camera in unknown state
• scs daq control in unknown state (problem caused by FADC not instantiated)
• SCS_XTD10_TPI/CAM/SHUTTER was in the UNKNOWN state: the camera cannot be pinged, probably it is disconnected. WE NEED TO FOLLOW UP WITH THIS
• HSLITS blades were in error and could not be moved, Leandro fixed this problem, the issue was at the PLC level and related to the encoder
• ESLITS imager and SCS POPin could not be moved, DOC (Dave) fixed this problem
• we could not propagate the unfocused beam to the SCS Popin, only up to M5 popin

plan:

• look for signal at the hRXIS
• optimize resolution by changing LEPM angle
• measure XAS using MCP
• look for signal at APD after moving the APD on the side of the sample that is not blocked by the L shaped knife edge

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

Dear all,

last evening Suren Karabekyan and myself did a short notice ZZ access to XTD1. The reason is that machine operators detected the lack of response on the Cell 17 Phase Shifter. The intervention was successful and around 20:30 we left the tunnel.

Regards,

R.

Attachment 1: Beam in SPB hutch with Si500

Attachment 2: Beam without Si500

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.

Dear all,

the closing report on this issue can be found in the following Alfresco link:

https://docs.xfel.eu/share/s/GzxORQOGToe_tiug7LIHhQ 

Regards,

R.

BKR changed the beam energy from 15 keV to 12.4 keV

Energy 12.4 keV

Repeatation rate 1.1 MHz

Average pulse energy 1.8 mJ

The late shift on the 13th fixed remaining problems with the DLD and the calibration pipeline.

The night shift was then able to collect data on O2 using the two-color mode. Systematic studies were done at different photon energies for both colors. This was done for full FEL intensity and 10%.

The day shift started to investigate if we see an effect changing the delay between the two colors. This turned out to be difficult because we lost the second color when changing the delay. BKR retuned for us with a delay.

Afterward, we asked BKR (Mathias and Mark) to re-tune the two color setup for short pulses.

Upcoming late and night shift should collect more data using the short pulses. Keep in mind to check and record the single pulse FEL spectrum upon each change on the undulator settings.

PBLM checked:  https://in.xfel.eu/elog/XRO+Beam+Commissioning/203

Solid attenuators checked: https://in.xfel.eu/elog/XRO+Beam+Commissioning/194

04 Apr 2023, 07:44 we realize that the SetpointsHED Macro lost all values, probably during the Karabo Crash. Since it is a macro, the values arent stored anywhere. DOC tries to recover. Meanwhile, we found the values for 3mrad, 2.5mrad and 2mrad in old screenshots and update the macro values from that. Saving those now locally in nextcloud/user/Alex.

04 Apr 2023, 08:17 Solution by DOC: Apparently the macro CAN save the values, and that was also done during the bringupdays, but they are only saved on the GUI Server which the macro was started on, in this case GUI2. However, when Karabo was restarted, the macro was started on GUI1, so the local save files could not be retrieved. DOC copied the old save files to GUI1 now as well so we could reload the old positions for all setpoints.

- Pulse intensity decreases drastically at XTD2 across the train

- the visualisation of our beam therfore needs to be compensated adjusting transmission

- beam shape and uniformity is different than previous days and it is unclear how much of this is related to real changes in the beam or an effect of the slope in the train. We are therefore spending more time than usual to investigate and align becuse we cannot correct the slope.

>50 pulses was requested for alignment explicitly as this is needed to setup the instrument for measurment.