Metadata of measurement_1.h5 

Experimental method: time-resolved electron diffraction experiment on MoS2 crystals
Location of the experiment: Fritz Haber Institute, Faradayweg 4-6, 14195 Berlin, Department of Physical Chemistry, Research Group Structural and Electronic Surface Dynamics  
Date of the experiment: May 5th, 2019 
Related publication / description of the experiment: http://arxiv.org/abs/2503.03363

Sample parameters  

material: MoS2 
sample provider: HQ Graphene
sample thickness: (35 +/-5) [nm] 
absorbed photons per unit volume: around 1.29-1.69x10^14 [1/cm^2]
sample temperature: 300  [K] 


Optical pump pulse parameters  

pump pulse repetition rate: 4 [kHz] 
pump pulse duration: ca. 50 [fs]  
pump pulse center wavelength: 590 [nm]  
pump pulse spot size at sample: ca. 150 [um] 
pump pulse incident fluence:  4.41 [mJ/cm^2] 
pump pulse angle of incidence: 10° off-normal  


Electron probe pulse parameters 
 
electron probe pulse repetition rate: 4 kHz 
electron energy: 70 [keV]  
electron spot size at sample: ca. 100 [um]  
electron probe pulse angle of incidence: normal  
diffraction geometry: in transmission  


Estimated time resolution of the experiment: ca. 150 fs 


Electron detector parameters: 
 
detector manufacturer: TVIPS GmbH, Germany 
detector model: TemCam F-416 
detector pixel size: 15.6 x 15.6 [um^2]  
detector binning: none 
integration time: 5 [s] 


Pump-probe scan parameters: 

97 discrete pump-probe delays are sampled between -10 ps and +50 ps (dataset "delays [ps]" in group "Measurement").
The pump-probe range is scanned 22 times in alternating direction.
At each delay point, the diffraction signal is measured for 25 s (5 burst acquisitions at 5 s), 
resulting in 2134 images. 

In addition, a background image (no electron probe pulse; with optical pump pulse) was recorded 
with the same acquisition parameters. This image contains the dark counts and optical pump laser 
light background. 

The raw diffraction images were processed in the following way:  

- The background image was subtracted. 
- The images were flat-field corrected to account for slightly different sensitivities of different pixels of the electron detector.  

Following these operations, an average image over all 22 scans is then obtained for each delay point, yielding 97 images.
These are given in the group "Measurement" in "images". In addition to the operations mentioned above, the following operations were performed on the averaged data:

- Each image was normalized by the average electron flux at the corresponding delay  
- Each image (2048 x 2048 pixels) was cropped to a region of interest (1300 x 1300) centered on the diffraction pattern so as to save space.

Difference images are also provided for each pump-probe delay in "Measurement" in "difference images": these are obtained by taking the difference between the diffraction pattern at some time delay and the equilibrium pattern (before t0)


The group "analysis" contains relative intensities of the inelastic signals close to Gamma, at Lambda, M, and K points ("data"). These were extracted using the procedure described in http://arxiv.org/abs/2503.03363.
Error bars obtained by averaging over the multiple scans are also provided as "error". Fits to the traces are provided as "fit".
The corresponding delay points are given in "Measurement" under "delay [ps]".