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last update 15/02/2010
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 Micro-XPS operation mode 

Operating procedures
Sample transfer
Microscope Alignment Procedure
LEEM operation mode
XPEEM operation mode
Diffraction operation mode
Dispersive plane mode 		  Maintenance
Venting
Pump down
Preparing a bake-out
Outgassing after bake-out
Channelplate HV ramping
SPELEEM analyser HV ramping
Prep chamber manipultor wiring

MICRO XPS OR DISPERSIVE PLANE OPERATION

The last two projectors of the imaging column, P2 and P3, are used to image the dispersive plane of the analyser. The dispersive plane appears as a thin line, and its intensity profile represents the photoemission spectrum. The probed area is selected by the field limiting aperture inserted in the image plane after the objective lens. This operation mode allows imaging an energy window of about 12 eV. It is used to acquire local XPS spectra from an area of 2 µm diameter.

micro-XPS
SPELEEM operation: micro-XPS mode

OPERATIVE INSTRUCTIONS

In dispersive plane operation mode one has to be very careful not to burn the detector with the intense secondary electron emission at very low energy. All the intensity is focused in a small portion of the detector (a line!).

NEVER SATURATE THE DETECTOR!
BE CAREFUL NOT TO PUT TOO MUCH INTENSITY!
Do not use more than 10% of the full camera range at exposure of 0.02 ms. In emergency, turn off the 18 kV high voltage, and check all the settings.
  1. The microscope has to be aligned in the imaging mode: please follow the instructions for XPEEM. Select the probed region of interest by moving the manipulator and inserting the smallest field limiting area.

  2. Before switching to dispersive plane mode, make sure of the following:
    • START VOLTAGE IS HIGHER THAN 30 eV, i.e. ENERGY IS SET FAR AWAY FROM THE SECONDARIES!
    • The analyser energy slit is not inserted. To remove the energy slit, retract it using the linear feedthrough until the large opening is reached. Keep retracting until the end of the opening. From that point, move back in 1 1/4 turns to center the opening.
    • The contrast aperture (30 or 100 microns) is inserted.
    • The grabber preview is running to detect immediately if the intensity is too high.

  3. Simply click on DP button in UMeasure (same in LEEM2000).

  4. Set the desired kinetic energy of the photoelectrons by changing the start voltage. Again make sure that this is not close to the secondary peak at low energy!

  5. At the end of the dispersive plane measurements, acquire an image of the e-gun spot! This gives the reference point for calculating the energies along the dispersion line. In order to do this, close the beamline. Slightly open the Wehnelt (until you see some intensity). Record an image, and save it to be later used in the analysis.

  6. Never leave the instrument in dispersive plane mode: it's dangerous! Remember to go to imaging mode after finishing.