SASE3 Summary of Maintenance Period and Ramp up activities

Maintenance

- Soft Mono motions (grating horizontal and grating pitch) were cleaned and lubricated

- Vertical slit encoders were double checked (without moving them) to exclude that Karabo errors are coming from them.

- Motors of Mirrors were inspected (without dismounting) to check if some strange noise is created during motion. The SA3 M2 Tx motor was very noisy at 0.035 speed and not anymore at 0.03. 

- Settings of acceleration and velocity was optimised together with EEE (Bernard). The noise at SA3 M2 Tx was disappearing even with 0.035 speed.

- M1 and M2 chillers had service (water filling) and were then set on again before closing the tunnel. For M5 and M6, cooling is off.

- Piezo controller for M1 was disconnected and removed. Therefore, the M1 piezos are unavailable at the moment. This was agreed with the experiments after it was found some instabilities in the beam position (beam was moving by itself sometime). 

- PBLMs were checked: https://in.xfel.eu/elog/XRO+Beam+Commissioning/76

Inst Dept Ramp up

- SA3 M2 RY was not moving. This took several hours to be solved. Temprary explanation: stepcounter value changed without any physical movement of the motor and later on, encoder was thought to be wrongly calibrated and thus adjusted. As a result, the motor position is lost and needs to be fiducialised again in the alignment.

- The performance of "Closed loop" and "Backlash Correction" was tested. The result is that the TY motors need to remain in open loop and with 'Backlash Correction' activated (value 2 microns). This is increasing the reproducibility of the positioning. The other motors could be used in closed loop if required, but then the Backlash Correction has to be deactivated.

- SA3 M6 RY encoder has an incorrect calibration at the moment. Please refer to the motor position only. We will work on a solution asap.

- The vertical slits (SCS, SQS, SXP) were checked and they move correctly.

- Several positions were fiducialised, that could be used as a starting point for Instruments fine alignment:
SXP 9mrad (8.9mrad) mono he premirror 937eV 
SXP 9mrad (8.9mrad) unfocused
SCS 9mrad (8.9 mrad) unfocused
SCS 9 mrad (8.3mrad) unfocused
SQS 9mrad (8.7mrad) unfocused
SQS 20mrad (18.5mrad) unfocused

- SEPS interlock was succefully tested: https://in.xfel.eu/elog/XRO+Beam+Commissioning/112


 

SASE1 Summary of Maintenance Period and Ramp up activities

Maintenance

- MC2 library update was deployed by EEE and most of the motors were tested afterwards
- Some motors were acting strangely: https://in.xfel.eu/elog/XRO+Beam+Commissioning/82
- As a rule, the Closed Loop and the Backlash Correction are atm incompatible and therefore you have to choose one of them. When a strong reproducibility is needed, the motor should remain in Open Loop and with Backlash Correction activated (2 microns for TY and 50 microns for TX, tipically): https://in.xfel.eu/elog/XRO+Beam+Commissioning/83|
- FXE mono1 bottom crystal was exchanged, realigned parallel to the beam. Recommissioning due WK5 together with FXE
- M1 and M2 chillers had service (water filling) and were then set on again before closing the tunnel. M3 is currently with cooling off.

Inst Dept Ramp up

- Several positions were fiducialised:
SPB alignment 2.41mrad 9keV
FXE alignment 2.4 mrad 9 keV

SASE2 Summary of Maintenance Period and Ramp up activities

Maintenance

- Many vibration tests were done.

- M1 chiller had service (water filling) and was then set on again before closing the tunnel. M2, M3 cooling is off.
 

Inst Dept Ramp up

- Positions reached:
MID 2.2 mrad at 9 keV 
HED - 9keV - 2.7mrad - B4C stripe

- checks for the stripes were done:
M3 verification of coating positions and horizontality or the mirror
MID alignment Pt stripe - vertical motion of mirrors with Euler

- for the stripes, we have now a watchdog telling if the mirrors are on the B4C or the Pt stripe (see image below)

Update of the damage tests at SQS.

Yesterday (15.04) SQS staff created a focused beam on our sample using a small YAG fragment we have placed on the holder.

Due to the unusual position, the beam is full of aberrations but it looked small enough for our purpose. Estimattion of the size is difficult atm but it is our intention to measure it with imprints.

We managed to align the sample 1 (silicon, uncoated) in grazing incidence at 19 mrad and found the damage threshold at current focusing conditions at around 100 uJoule (looking on the SQS XGM).

We managed to align also on sample 2 (silicon, B$C coated) at the same grazing angle and we found a threshold at around 200 uJoule.

We started to do systematic spots at various energies, using the GATT

One difficulty is that the manipulator is not enough precise to scan several mms in grazing incidence, the sample has to be realigned along the scan and we cannot find a clear centering on the sample due to the lack of reproducibility.

In the late shift we started to do imprints to characterise the beam spot.

Overall the experiment is on a very good status. Until now, we explored only single pulse damage. Today (16.04) we will try multipulse damage and single pulse damage at 9 mrad.

 

Today we comtinued the program, changing to 9mrad amd 15mrad and doing also multipulse. We had a short interruption at around 15 to extract some samples and to realign Sample 3.

shift summary from Saturday 15.04.2023:

Tasks:

- Calibration of Euler MDL

- Vibrometer measurements at M3 using the RY piezo

Beam was aligned to MID popin

we used values stored in MID setpoints 'B' but went there manually, using the EulerMDL

M1 - X value was corrected, as we found the center of the beam/mirror to be at 6.4mm - calculated beam angle after M1 is 2.14mrad

M2 - values slightly differ from saved setpoints but were quite well met using EulerMDL to reach the same beam position

M3 - we had to remove it a bit further from the beam, as it seemed to intercept it, when we first tried to get the beam through. This might in the end not have been necessary

End of shift:

beam aligned to MID

preabsorber in

SRA fully open

Mirror positions and beam position on the imagers for 14.8 keV SPB, 2mrad

ATTENTION: the alignment was difficult due to the strong background from SA3 with 500 pulses. For the future, maybe SA3 could reduce to single pulse during alignment of SA1. This would make the process easier.

fig1: M2 popin

fig2: M3 popin

fig3: SPB popin

fig4: beam transport overview

fig5: mirrors positions

fig6: for comparison, this is the M2 popin image when a strong background from SASE3 is coming (500 pulses, 3milliJoule, 2.1 keV)

This has several implications:

- ALL PREVIOUSLY SAVED RY POSITIONS ARE OBSOLETE!

- Ry values seem to have changed by a factor of 1000

- Accelleration and decelleration have been reduced significantly.

- MOTOR WILL STILL MOVE FOR SEVERAL SECONDS WHEN PRESSING 'STOP'

-Motor velocity has been reduced

Summary of today's activity:

• Beam handover ~ 3pm.
• SA2 mirror set tp B4C.
• SA2 Rough alignment to MID & HED @ ~ 2-2.5 mrad ==> img 1, 4, 5 & 6
• SA2 HED-Preabsorber position check with x-ray (working) ==> img 2 &3
• SA3 M6 mirror Switch check (seems to be working)
• SA1 rough alignment to SPB (M1,M2) at 2 mrad ==>img 7&8

Mirror pitch motors Ry were tested after scaling was changed to um.

Tx and Ry motor positions were calibrated to their measured physical positions.

ALL PREVIOUSLY SAVED SETTINGS FOR SASE2 MIRRORS ARE OBSOLETE!

New mirror positions for 9.3keV ; 2.2mrad ; B4C stripe are stored in MID-setpoints and HED setpoints

Please check the respective ELOG entries from July 20th

Beam aligned to SPB Pop-In https://in.xfel.eu/elog/XRO+Beam+Commissioning/185

Beam aligned to FXE Pop-In https://in.xfel.eu/elog/XRO+Beam+Commissioning/187

Vibration tests: https://in.xfel.eu/elog/XRO+Beam+Commissioning/188

Camera of M2 may not be working. Please check.

Position stored in XRO setpoints - F and HED setpoints - A

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

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

Alignment to HED: https://in.xfel.eu/elog/XRO+Beam+Commissioning/205

SA2 - divergence with various M2 bender positions  HED - https://in.xfel.eu/elog/XRO+Beam+Commissioning/200

SA2 - divergence with various M2 bender positions MID - https://in.xfel.eu/elog/XRO+Beam+Commissioning/196

Issues with HED PBLM blade in SA2: https://in.xfel.eu/elog/XRO+Beam+Commissioning/195

Vobration measurements could not be done https://in.xfel.eu/elog/XRO+Beam+Commissioning/207

End of shift:

SA2 left with preAbs in

machine wanted to increase intensity

Second iteration and sanitty test for vertical mirror motion (Y) and vertical beam alignment (ROLL)

Vertical motors were calibrated and offsets saved in Euler MDL (no calibration of motors done so far - this should be performed during ramp up after WMP)

Calibration values are

Rz=-8.7805

Ty=-4.11

Rx=-4.53

PITCH=8.58

ROLL=4.2063

Residual horizontal parasitic motion is within 2urad for M3 - for vertical beam alignment, the residual horizontal parasitic motion is even less.

With Euler MDL, mirror can now be moved and the beam will mostly stay on the experiment screen.

Setpoints for HED set in XRO setpoints 'B' (8.8keV B4C)

euler MDL was calibrated for all three mirrors.

Optics setpoints saved in XRO setpoints for MID and HED

End of Euler shift: all 3 SASE2 mirrors are now working with the Euler MDL.

We left the beamline aligned to HED, with M1,M2 on Pt for upcoming HED experiment at 18 keV.

Pre-absorber closed, CRL1 out, Solid attenuater with some diamonds.

The Euler MDL was updated, so that velocities are restored to standard values also after the stop button was hit before motion was finished.

Please be aware that due to the synchronized motion, which is neccessary to keep the beam on the screen, some motors may move for a longer time with very slow speed (main reason - backlash compensation). We are working on a solution with a minimum speed.

!!! Euler calibration values are NOT connected to motor velocities and it is crucial for the functionality of the MDL that these stay as they are !!!

We found reflection of M3 on M2 popin, but could not locate the beam on HED PBLM nor HED_XTD6_SDLBM-1

scanning both horizontally and vertically around previously saved positions on M3 popin.

managed to get beam through to sdlbm-1. No beam found downstream of that.

Saved motor positions in last picture

ATTENTION: M3 MOTORS STILL NOT CALIBRATED AFTER MECHANICAL INTERVENTION DURING WMP. EULER MDL NOT WORKING RELIABLY FOR M3