achievements

• optimized EOS signal from FEL-induced THz emission from STE on Sa of PAM
• reduced chirp to increase timing sensitivity to 9fs / pixel of PAM
• STE-based PAM measurements at fixed delay and delay scans. 
• after FEL down at 6am, continue with PAM measurements without BAM fast feedback mode (stopped after FEL back)

issues

• none

# Shift Summary

Achievements
 - Found RIXS signal from CuO as well as off-resonant elastic line signals from NiO and CoO
 - Found a potentially optimal exit arm setting and checked theta angle of sample
 - Determined energy calibration

Problems
 - Overall signal levels were quite low of CoO and NiO samples. This meant we had to work with open exit slits. Long scans would be required for optimization at HR conditions
- Interpolation procedure was giving lower signal as compared to direct integration. Algorithm needs to be checked. Analysis with no interpolation and curve correction is available in Software folder LLG/elastic_line_analysis.ipynb

Plan for next shift
- continue with optimization of hRIXS resolution

Achievements

• Used scanning of liquid jet to improve S/N
• Measured x-ray PP XAS as a function of the delay between the two X-ray colors
• Scan energy of probe pulse with fixed pump energy

Problems

• No clear signature of ionized states observed in XAS yet

Achievements:

1. Replaced focusing lens of PP laser and measured focus with knife edge, focus is about 720 micron vert. & 600 horizontal. Horizontal x-ray spot size is 220 micron
2. Adapted fluence calibration for the new spot sizes
3. Optimized spatial and temporal overlap with new lens
4. Performed optical and x-ray intensity & sample damage tests. We found that up to 15% GATT and up to 50% laser power are okay to use, without altering the sample.
5. We started to collect hRIXS data at positive (1ps) and negative (-2ps) delays.

Problems:

1. Few beam dumps.
2. BAM scene not working
3. The new (?) centroiding function produces spectra with different intensity for acquisitions with the same settings. The old algorithm seems to work well.

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

• Located flat jet and attempted measurement of XAS at several incident energies 1300, 1305, 1315 eV

Problems

•  We have difficulty locating the beam on the sample
  • We have not found a signal on eith of the diodes in the Chem chamber.
  • Knife edges with the viking are daoable but require more extended analysis
• Jet froze due to a leakage from the side of the chip. The ice crusher has been avoided to solve
• The filter in the hRIXS was broken and had to be relplaced.

Achievements

• Measured self-refreenced XAS spectra with single color baem at the Mg K-edge

Problems

• Liquid jet required some mantanence during the shift
• Some newton detector images filled with NANs

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.

achievements:

• FEL beam realignment because pointing was off since we had 0 pulses during the night
• coarse timing was found
• knife edge scans of FEL to achieve twice the PPL beam size

problems:

• several machine interruptions, partially due to corss-talk with sa2 and 4.5 MHz oparation
• gate valve before KB XOX/GV3 goes into interlock and then stays closed, probably due to pressure spikes

# Morning shift summary

Giuseppe, Martin

* achievements
- continued tr-RIXS measurements
- good beam conditions
- added new alarms to give warning if parameters are wrong for certain measurement type
- created new karabo device to calculate the fluence and train-averaged pulse energy in nJ from pulse-resolved HAMP values (see new scene in Main)

* problems
- none

achievements:

• calibration of exit slits
• measurement of Cu L3 edge
• moved hRIXS to nominal settings for Cu L3 edge

problems:

• hRIXS motors could not be moved remotely, the problem was finally understood: GTZ had been moved manually into an interlock condition, going then to remote operation bring the motors to error state, it is then impossible to go out of error state from remote operation if there is also an interlocked state. In this case, the solution is to move the motor away from interlock state manually and then move to remote operation.
• vavle with filters in front of grating chamber cannot be moved: problem unsolved, please Martin have a look at it.
• DA online analysis tool for XAS was not working, DAC contacted Oleksey from DA and problem was fixed

plan:

• optimize beam dimension for hRIXS
• find rixs signal and optimize resolution

Achievements:

1. Performed tr-RIXS on peak A, B, and C at 2.4 mJ/cm^2
2. Performed tr-XAS on peak A at 3 fluences
3. Performed tr-RIXS on peak A at 4 mJ/cm^2

Problems:

1. BAM delay line compensator was not working due to incorrect macro. DOC and LM fixed the issue.
2. Delay line scan of hRIXS camera was not working as it was still configured for Viking. MT fixed the issue.
3. The new centroiding algorithm (provided natively by the 4137 kernel) is not consistent with integration mode. For the time being, we use an older, manually configured centroiding algorithm developed for a previous user beamtime.
4. tR-XAS results show large changes, but these large changes were not reflected in tr-RIXS.

Achievements

1. Start cooling down the sample
2. Align the beamline and deliver the beam into the sample
3. Performed knife edge scans and enlarge the beam horizontal size to 350 um
4. Tuned the VHM bending by checking the hRIXS resolution
5. Performed energy calibration on the 1000 l/mm grating
6. Check XAS and RIXS of the NdNiO3 sample at 20 K, normal incidence, and peak A

Problems:

1. Nothing of note

Shift Plan:

1. Check static RIXS at a few different configuration
2. Check damage threshold with x-ray and laser
3. Find spatial and temporal overlap between laser and x-ray
4. Performed pump-probe XAS and RIXS

Achievements

• Moved spectrometer to 1000 ln/mm and began alignment

Plan for next shift

• Continue optimization of spectrometer with 1000 ln/mm grating

Problems

• At some point we lost signal from the spectrometer and it took some time to find it
• There were several beam lossed between 12 and 13h

Achievements

• Tested MCPs and APD for XAS
  • Both MCPs give a good XAS spectrum with no amplification, but small MCP requires higher bias voltage
  • No fluorescence signal observed on the APD
• Measured XAS of both samples
• Measured static RIXS of under-doped sample

Problems

• None

Plan for next shift

• Sample alignment (half clip+diffraction)
• Switch AFS laser to burst mode and find timing

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)

Activities:

• correctly positioned magnet
• moved detector upstream and found small beamstop
• Recorded SAXS
• Started tr-SAXS

Problems:

• The SAXS images from laser-excited samples showed unexpected variation between different size rings, central point (ie not a ring) and no scattering.