Energy Dispersive X-Ray Spectroscopy (EDS/EDXS)

From LPDwiki

Shortcuts

1. ESC → Abort key if anything goes wrong

2. To go Live → F6

3.To restart → Stop UI (top command window)


Starting the Software and the Instrument

1. Login into Badger to activate the instrument (the desktop screen on the left).


2. Login into the instrument itself using the desktop screen on the right.

  • The login information changes on a monthly basis and is written out on the Post-It notes attached at the bottom of the screen.
  • Note: After logging in, Application Status will come out. If only Errors are displayed, that is normal → Clear it all.
  • If some Operational errors show, call CNM2 Support.


3. On the middle desktop screen check: Sample Exchange Window → Vacuum → Make sure five green boxes are on, otherwise call CNM2 Support.


4. Vent. Close out all windows while it is venting.


5. Once pressure is ⅘ down or the slight hissing sound starts, pull out the chamber and load the sample. Close carefully.


6. Start Pump even if the instrument is still running (venting).


7. While pumping, warm EDS up → Aztec software (the middle computer):


8. Name the project (it is saved in My Documents).


9. Control EDS detector xMax50 (lower right) → Operate.


10. Blue light on the machine should be solid (thermal indicator).


11. Position should be In on Detector Control.


12. Point & ID should be selected instead of Map.


13. Go to CCD camera (lower right screen) and check that it is 45 mm stage rise at the z-axis (Navigation tab). Bring the stage manually to 7 mm.


14. Detector:

14a. ETD → Secondary Electrons → 250V.

14b. Contrast 1, Brightness 0, Gamma 1.

14c. Check that there is a diagonal line displayed.


15. Fill out the recording sheet with the following information:

15a. HVG under the vacuum (Sample Exchange Window).

15b. Chamber pressure (IGP1, IGP2).

15c. Put system to sleep to cool off if ion beam is in µA (emissions current).


Sample Analysis

1. Electron Beam → Beam ON.


2. Pause CCD after the sample is moved up, so that the light doesn’t interfere with the data.


3. Dwell time should be around 50 ns (the time el. beam stays on each pixel).


4. Resolution should be around 1536 x 1024.


5. In Beam Screen , start with 10 kV, 13 nA and find the sample.


6. Dead time is the ratio of beam being on/off. Ideal is 30% - 70%.

  • Change the dead time by changing the spot size ( e.g. 13 nA to 3 nA) OR
  • Next to the Ratemeter → Settings → Process time longer for new samples .


7. Resolve at x1 000 magnification and increase incrementally to x3 000.

7a. Magnification → Focus (fine, coarse)


8. Adjust Stigmator (move the pointer on the Beam window).


9. Adjust Lens Alignment (right click to change to coarse for easier stabilization).


10. Zoom in and find the plain sample.


11. Make sure specimen geometry is unchecked.


12. Predefined elements → Au, Ag, Cr → Include.


13. Using middle screen start measurements.


14. Make new site for new images.


15. Scan Image:

15a. Settings (Image Scan: 2048, Dwell time 5 µs) → Start.


16. Acquire Spectra:

16a. Settings (In order: Auto, Auto, 5, Auto, Input → Start

16b. Peak labels can be deleted in Auto ID → Click on peak → Exclude


17. Calculate Composition (atomic %) → Acquire Spectra

  • Note: There is a fast scan option for one point measurement, but is overall less accurate measurement.


18. Save the generated data: Report Results (drop down menu) → Site Report → Goes to a folder.


19. Copy the report: Shared Data → Copy the Report.


After Data Acquisition

1. Middle Screen → Position OUT (lower right tab) → Thermal → Standby → Light on the machine should switch to yellow.

2. Beam screen → Beam off (wait for hissing sound to start).

3. Vent.

4. File → Save Project

5. Unload the sample → Pump → Stage (tab at the top of the screen) → Home Stage.

6. Once pressure starts decreasing → File → Log off.