Achievments:

- Align DPS to remove clipping of X-rays

- Get better focusing of PPL in the chamber

-Coarse timing with SIGNAl of OPA

-Switch back to 3 um PPL settings

Problems

-It was hard to work with DPS without motorized stages

Achievements:

1. Performed knife-edge scan. The beam size is currently at 5 um x 120 um.

2. Aligned the spectrometer at O K edge (2.8 pixel FWHM, 110 meV resolution, 4800 resolving power)

3. Performed energy calibration at O K edge (39.3 meV / pixel)

4. Setup the liquid jet environment for water.

Problems:

1. The elastic signal at CoO sample is very weak, so the alignment was done on the multilayer sample.

2. The motor of the ice crusher has some movement problem.

achievements:

• knife edge scans of OL to find lens position corresponding to the smallest beam size
• knife edge scans of FEL to determine the position to proceed for spatial overlap
• liquid jet was set up and it's running since afternoon
• measured x-ray absortion via the diode in the CHEM-DIAG

problems:

• difficult to perform knife edge using 3 um after finding rough spatial overlap useing the green laser. The issue is the following: becasue the diode does not see the direct OL beam but rather we see scattered light at the diode, even when the direct beam is blocked by the sample holder
• since spatial ovelap cannot be found we siwtch program
• APD voltage device goes into error above 310 V and at 310 V after some minutes it goes also into error ->
• the APD signal shows strong fluctations in the background

achievements:

• change the optical laser to 2 um
• found focus of 2 um beam
• found saptial overlap
• course timing was checked
• looking for fine timing using SiN

problems:

• fine timing signal not seen yet

Achievements:

- Improved the vacuum of the chamber slightly

- Found the spatial overlap between FEL and jet

- Found the spatial overlap between FEL and PP laser on pBN (but may not be the same on liquid jet)

Problems:

- Beam loss for 6+ hours, from 23.00h to 5.15h due to fuse tripping in the laser system of the electron gun

- While fixing the beam loss, the machine seemed to have trouble with timing. So if fine timing can't be found, perhaps it's worth it to check rough timing again.

- The rough pumps in the room are full of water. We solved this by taking 2 rough pumps and connecting them directly to the chamber.

- The antenna cable is too bulky. So the sample plate should only be rotated to -90 deg (-358.65 actual), as rotating the other way will severely tilt the sample plate.

Achievements:

- we replaced broken SMA cable, and added an angle-connector at sample holder to aid the sample rotation when moving diagnostics to the flat jet

- we double-checked coarse timing and x-ray beam size

- we found t0 on SiN

- setting up RIXS with time delay steps for the night shift program

Achievments

-RIXS scans at different delay times and x-ray energies

-Cross check fine timing

Problems

-Nozzle was frozen. Pump was in error state.

Achievements:

1. Continued measuring time-resolved and static RIXS on water (run table in elog entry #103)

2. Periodically checked spatial overlap and BAM compensator in-between measurements.

3. Refilled and changed cold traps when necessary.

Problems:

1. Some icing issue, solved by changing the nozzle.

Achievements

• Found RIXS signal from liquid jet
• Measured static RIXS and PFY-XAS spectrum of Co(cp)(CO)2

Problems

• hRIXS detector has a data latency issue and images were not being recorded in the DAQ. This required ~2-3 hours to solve plus time lost during night shift.

Plan for Next Shift

• find temporal overlap between X-ray and laser

Activities:

• Found coarse and fine timing between FEL and PPL at 266nm
• Set up for tr-RIXS during the night

Problems:

• 2 fastADC channels appear to be dead.
• Optical locking of the PPL syncronisation system took a very long time (> 30 minutes)

Activities:

• continued tr-RIXS scans
• tried to find ways to mitigate the energy drifts of the mono (see below)
• confirmed in user data that the FEL-PPL timing was not changing (see below)
• setting up for tr-RIXS at beginning of night shift

Problems:

• the mono energy has been drifting, presumably due to warming of the grating.
• automatic correction of the elastic line in the RIXS data was not working reliably
• we suspected a timing drift, but it seems that the monitor (photodiode + oscilloscope) itself is drifting. That's a new one.

Achievements:

• measured the new sample, Silane, with different time delays

Problems

• Tuning of SASE2 led to a 50% decrease in the SCS XGM intensity without affecting the SASE3 intensity. It also caused a jump in the BAM value

Activities:

• Measured tr-RIXS spectra on user sample in silane solvent

Problems:

• Sometimes the PPL shutter cannot be opened from the control room after searching the hutch.

Achievements

• Found coarse timing between XFEL and optical laser

Problems

• Did not see a observe fine timing signal from silicon nitride measurement

Plan for night shift

• Continue with liquid jet optimization and static measurements

Achievements

• Optimized BOZ for Co and Fe
• Estabilished Stable liquid jet flow with 30 mM Fe(bpy)3

Problems

• Jet froze several times
• Chamber warmed up earlier in the day. This led to a "dusting" of CNCbl on many surfaces and in the large turbo. We cleaned the turbo with ethanol.

Plan for Night Shift

• Continue measuring stitic XAS with BOZ scheme.

Achievement

• Measured tXAS at the Fe L-edge of Fe(bpy)3 using both delay and energy scans. 

Issues

• The cold traps ran empty on the chamber resulting in a pressure spike that interlocked the DSSC
• The rough vacuum of the chem DPS degraded causing TP5 to go into error. This resulted in valve closing and stopping the measurements
• Jet froze twice

Achievements:

Collected more scans on cyanocobalamin, both delays scans and dynamic XAS

Issues with bad signal in beginning but good signal in the last hours

Overall successful beamtime, demonstrating new transmission/absorption setup with liquid jet and DSSC

Problems:

None

Achievements

• knife edge scans of FEL beam, 30 um x 30 um beam size
• aligned beam stop in front of camera
• triggering pattern tested and works, still need to test with laser and XGM

Problems

• Y motor of beam stop doesn't reach the desired up position
  • had to move the entire camera instead
• Once or twice scanner Y got into error during knife edge scan, resetting the target position to the actual position and pressing move helps.
•  

We report on an issue regarding the bunch pattern: The bunch pattern read by SCS_RR_UTC/MDL/BUNCH_DECODER shows 48 pulses, but we instead use 50 pulses.

Currently, we have a separate RF window and our 1st pulse Id is 2604. We operate at 2.2 MHz, and as required, 50 pulses. See attachment 1.

This means that the last two pulse Ids are 2700 and 2702. However, these values exceed the number of pulses allowed, and the way the bunch pattern is read (SCS_RR_UTC/TSYS/TIMESERVER:outputBunchPattern,
and the middle layer SCS_RR_UTC/MDL/BUNCH_DECODER) cast the array to 2700 values, so that the number of pulses read is 48 instead of actual 50.

We confirm that we indeed have 50 pulses, as seen by the XGM and by photodiode traces showing 50 peaks.

Since our data analysis strongly relies on the bunchpattern table, this is a critical issue.

For now, the users agreed to use 48 pulses instead of 50 pulses to facilitate the data analysis, but this issue should be investigated.

DOC was called, ITDM is aware and helped finding the reason.

edit 20 Apr 2023, 16:26 : redmine ticket https://redmine.xfel.eu/issues/151949

Achievements

• found larger beamstop
• found center of pinhole and bender settings for beam size
• checked jitter of beam on grating, looks like jittering is large, to be further investigated offline
• checked that patterns are working for the night, to be continued by night crew

Problems

• Major problems with scanner Y, as during the previous runs. Reset axis, Reset and adjust the target position to actual position + move to get out of error.
• Problem with bunch pattern (see separate entry in Operations elog)
•