How to perform XPS measurements with VSW

IN BRIEF: Remote PreAmp of IS OFF and disconnected.
Ground the sample: Ground cable connected.


0. Set the Entrance slit and Exit slit opening with the MAIN PANEL.VI (or for expert users from Motor Control.VI) to set the required Energy Resolution.
Press =>. Select the Element (Entrance Slit), the Action (Opening). Set the value (absolute) between 10 and 50 and press MOVE. Select the Element (Exit Slit), the Action (Opening). Set the value (absolute) between 10 and 50 and press MOVE.

1. XPS onoff.VI has to be ON. (Select ON, Press inside the circle until a point appears, Press=>). Then Press OK in the Popup window and wait until the green buttom gets red).

2. Switch OFF the Remote PreAmp of IS (if it was connected)

3. Disconnect the Remote PreAmp of IS from the BNC of the manipulator.

4. Connect the Ground cable to the BNC of the manipulator in order to ground the sample.

Note that for XPS the Keithley is not a good ground. Therefore also in this case disconnect the Remote PreAmp from the BNC, after having pressed OFF (on the main panel under the blue light, the blue light will get off) and connect a ground cable to the BNC.

5. Counter Setting.VI. Check that only I0 is selected (ON) in the Counter Setting.VI (while XPS, IS and IREL must be OFF).

Note: all the scanning VI (Scan energy, scan motor, scan XPS, scan resonant XPS,..) have to be STOPPED before using Counter setting.VI

6. Align the beam on the sample using the TV screen, by moving X and Z with Y=25 and theta=180&deg. Some reference XYZtheta positions (center of the VG sample holder) of the manipulator are:

x=23.2; y=26.7; z=9.45; theta=180° -NORMAL INCIDENCE (SG3 grating)

x=25.9; y=29.72; z=9.45; theta=240° -NORMAL EMISSION (SG3 grating)

7.Set Energy and Undulator.VI. Use First harmonic when possible (at 2.0 GeV up to about 720 eV, at 2.4 GeV up to about 800-900 eV) or third harmonic for higher energies.

8.Scan XPS 2008.VI. Make a wide scan. Pass Energy can be selected from 5 to 90 eV. Typical time is 1000 (1 sec per point). The delta will be automatically chosen by the program (the value closest to the step set by the user compatible with the selected pass energy). Minimum Kinetic energy is 30 eV (default operation mode). On special request the operational mode of the analyser can be changed (by changing the CAEN connections-hardware) to measure kinetic energies between 0 eV and 100 eV (Low Energy Mode).

9.XPS Survey.VI. Optimize the Y and or change the angle. Set maximum kinetic energy, pass energy and time=500 to select a core level that you want to follow, the VI will show you in real time a window with the core level (the energy window will be proportional to the pass energy). For flat samples Y is around 25. You can then rotate to normal emission (theta=240°) while following the chosen core level count rate. You will need to adjust X and Y if the sample is not mounted at the horizontal center of the sample holder).

Last Updated on Friday, 20 April 2012 11:35