LEED

Both preparation chambers are equipped with Omicron SpectaLEEDs. We apologetically offer you Omicron’s LEED control software, installed on the endstation laptop, for operating them with the all-digital power supplies. There are some important quirks to be aware of:

  • The software will not run unless:

    • The control electronics are switched on

    • The USB cable from the control box was the first USB cable plugged into the computer.

    • The uEYE LEED camera is plugged into the computer

  • If the software is closed or the laptop lid is closed, the filament current is immediately dumped to zero - please avoid this.

  • Eventually it will stop accepting any keyboard entry. Values can only be changed using the mouse, or by copy-pasting in values you have written into a text editor. You can fix this by restarting the program, but it will require a slow filament ramp down and back up, see above.

  • By default the filament current is locked to 1.7A. To get the extra 50-100mA you sometimes need, switch to the higher current range.

To save an image, right click on it and choose ‘save snapshot’. It will include all metadata about the settings in the image.

When working at beam energies below 50eV it is important to bring the LEED with its mu-metal shield as close as possible to the sample. Don’t forget to retract again when you’ve finished before moving the manipulator away, or there may be a collision.

In both chambers there are saved manipulator positions which should reliably place the beam in the center of the sample plate.