Reciprocal Space Mapping (RSM)

Asymmetric RSM Procedure

Load Sample

• Remove sample stage and its holder by pushing the back tab in

• Center your sample on the stage and carefully tape the corners to the stage

• Replace the stage and turn to lock

• Put in the adequate slot size (e.g. 10mm)

Run Sample Alignment

• Select MER Asymmetric RSM high resolution PB-Ge(220)x2

• Button 2 - Sample Alignment:

  • Execute as normal (should be 0.5 thickness, 20 width, 20 height)

Put in Ge(220)x2 Monochromater

• Unplug the Soller slit from "RPS"

• Remove the Soller slit it using the allen key

• Carefully replace it with the Ge(220)x2 monochromoter (in plastic bin in filing cabinet)

  • BE VERY CAREFUL, DO NOT DROP IT OR TOUCH THE WINDOWS

• Install the monochromoter with the allen key

  • Plug it in to "ROD"

Analyzer Alignment

• Button 1 - Analyzer Alignment

• Ensure analyzer mode is Ge(220)x2

• Ensure align is set to 2theta=0

• Execute

Rocking Curves

• Process > pick your substrate

• Process > Diffraction Space > 004 > "Select" > "Move gonio"

• Button 3 - Rocking Curve Pre-Measurement

  • Make a folder for your RSM scan and save each next alignment step data for debugging as needed!

  • Run Recommended Sequence (not "move origin")

  • Execute

• At this point, be sure to watch the curves carefully and ensure the max values are being saved where they should!

• Make your layer stack

  • Choose substrate and add layer in "edit crystal"

  • Choose lattice constants, pick which atoms are in it, add elastic coefficients in "elastic stiffnesss"

  • "renew" to save

  • add layer --> choose new crystal

  • normal + incident for all layers

• Process --> diffraction space

  • Click 224 and select "move gonio" --> X-ray arm (left) should go up and receiving arm (right) should be grazing parallel

  • if the opposite happens, choose -2 -2 4 instead.

• Button 4 - Rocking Curve Pre-Measurement

  • optimizing angle phi

  • select customize conditions

  • If this fails, and the output is flat, change the range from -45-45 deg to something wider (-60 - 60 deg perhaps)

    • Then set the new value: control --> manual control --> phi --> check manual

• Buttons 5-8 - Rocking Curve Pre-Measurement, can be run together

  • Hit big EXECUTE button from step 5 (after choosing save locations for each step and hitting "OK")

  • unlikely to fail

• Return to Process --> diffraction space

  • Size pink block to set up scan area

  • Hit Apply, do NOT move gonio

• Button 10 - Set up the RSM

  • save it properly (w/224)

  • ISL (incident slit length), set to the slit size you used

  • Detector type: D/tex ultra

  • mode: omega step/2-theta/omega scan

  • use with 0 alignment

  • Check "set RSM origin" then "read current position" then uncheck

  • Click "Set DSS range"

  • EXECUTE

RSM Analysis

• Open 3d explore software

• Open your file (it is a 2D .ras)

• Set the coordinates

  • Process > Coordinate Conversion

  • Select Qx, Qy, Qz

• File > Export > Data as .txt

• Siff has Matlab code to plot this data nicely

  • Simply run the Matlab code and follow the directions, use the saved .txt file

  • You can adjust the axis ticks as needed in the code, otherwise it doesn't need to be changed

  • Click the color scale to select a new color scheme

After Scan

• Remove PB-Ge(220)x2 and reinstall the Soller slit with the same procedure

  • Remember to be very careful!

• Replace the sample stage with the alignment stage (inside the XRD "floor")

• Run a high resolution PB-Ge(220)x2 optics alignment

• Put the sample stage back in

• Shut down the XRD as needed