Welcome to CHESS <QM>2 Sample Alignment

High Dynamic Range Reciprocal Space Mapping (HDRM)

Basic Theory - HDRM

High Dynamic Range Mapping (HDRM) is primarily a method for studying single crystal samples, although it can also be effective for studying thin films. HDRM aims is to rapidly study wide regions of reciprocal space, collecting the intense Bragg peaks required to refine crystal structures along with weak features associated with superstructures, and the slowly modulated scattering associated with phonons and short-range order[1].

Single Crytal Alignment

Basic steps for single crystal sample alignment - HDRM

SPEC terminal and User Interface (UI): Data Collection is visible at the 4B computer

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Step 1: Manually stage: center the sample to the beam 
        FOURC> umvr samz 0.1 (relative motion of the sample movement up (+) and down (-)) 
        FOURC> umv phi 0
        FOURC> umv phi 180
        Move x and y to make the sample to the cursor
        FOURC> umv phi 90
        FOURC> umv phi 270
        Do it iteratively until the center of the axis match the sample position

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Carefully and slowly insert the sample in the top of the sample stage

Step 2 : Create new sample file 
  # Create newfile from the SPEC terminal, you need to provide acurate Element Name (K, Sc etc), special character does not work (.,:" etc)
  # samplename : chemical name of your sample, make sure you created folder in your directory

              FOURC>newfile <samplename>



  # Look the table in the googgle doc
  Provide all the correct informations for metadata in the server


  | Sample name | chemical formula | Crystal Structure | Space group | Space group #| Unit cell parameters | 
  | :----------:| :---------------:| :----------------:| :---------: | :-----------:| :--------------------:
  |   CeO2      |       CeO2       |       Cubic       |   Fm-3m     |    225         |a=5.41, b=5.41, c=5.41, alpha=90, beta=90, gamma=90
  | :----------:| :---------------:| :----------------:| :---------: | :-----------:| :---------------------:


  # sample_chemical_formula -- Provide chemical formula of the sample (e.g AV3Sb5): CeO2
  # crystal_system_rt -- Provide room temperature sample crystal system : cubic
  # sample_space_group -- Provide the sample space group :Fm-3m
  # sample_space_group_number -- Provide the sample space group number : 225
  # sample_unit_cell -- Unit cell dimensions  (units: angstrom) :  a = 5.41, b = 5.41, c = 5.41, alpha = 90, beta = 90, gamma = 90
  # phase_transition -- Will the sample undergo a phase transition during the experiment? If yes,what are the temperature and space group? (default: ):N.A

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Step 3: Go to the Data Collection User Interface (UI)
 # Go to User Interface : Sample Information tab and  only put the desired sample name

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check the signals

Step 3 : If you want to check the best height for the sample (finding smaller sample best position) 
  Go to heightscan tab 
  1. Click Preview
  2. Click Run Height Scan

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    a) Data will save at 'tiff' folder (Example : /nfs/chess/id4b/2026-1/sarker-0000-a/tiffs) inside the user folder at id4b
    b) Check the quality of the datasets at nexpy, DONOT Double click the image, the program will crush
    b) Go to the best position of the sample

  FOURC> umv samz <position of the sample>

Step 4 : Take a look at the height scan data

  • Step1 : Go to 'File' tab
  • Step 2 : Go to 'Import' tab
  • Step 3: Go to 'Import image stack'
  • Step 4: Go to desired file location
  • Step 5: Select the folder (it will not show any images)
  • Step 6: Select the images (mostly 50-60 images)
  • Double clicked the stack images
  • Go to the signal and click log scale
  • Go to z tab and press forward (it will go through the images)
  • Find the maximum signal in the height
  • Go to the terminal FOURC > umv samz

Quick video on 'heightscan' visualization (there is text below as well)

Step 5: Run Single Temperature scan 
  1. In the UI, insert desired temperature (eample: 300K)
  2. Desired exposure time

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    #Notes: the scan
        - It will vary chi, theta and phi angle
        - Collect data phi 0-365 with 3650 images (1 degree/frame)
        - You can the change the exposure time (if needed)

    # Data will save at raw6M in id4b folder (Example : /nfs/chess/id4b/2026-1/sarker-0000-a/raw6M )
Step 7: Check data nexpy

Please look at the Data visualization - Nexpy section

Step 2 : Take a look at the priliminary data after data collection

  • Step 1 : Go to 'File' tab
  • Step 2 : Go to 'Import' tab
  • Step 3: Go to 'Import image stack'
  • Step 4: Go to desired file location
  • Step 5: Select the folder (it will not show any images)

  • Step 6: Select the images (mostly 50-60 images)

  • Double clicked the stack images

  • Go to the signal and click log scale
  • Go to z tab and press forward (it will go through the images)

Quick video on 'collected data' visualization

Temperature modify and collect data

Change temperature from 300K and 90 K (if you are at Nitrogen atomosphere)
  • Step 1 : Set the desired Temperature on the Threextal Scan tab at UI

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  • Step 2 : Wait for temoerature to go to desired temperature
  • Step 3 : Modify Temperature and Count time (if needed)
  • Step 4 : Click Preview
  • Step 5 : Click Run Scan

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