LEED

LEED is available in the large preparation chamber (Omicron SpectaLEED) and the small ‘top’ chamber above the analysis chamber (OCI BDL600IR).

The camera is shared between the two - a USB connected Blackfly BFLY-U3-13S2C. Connect it to the nearby desktop PC with the long blue micro USB-3 cable. The camera viewing software is launched from the desktop via the ‘LeedView’ shortcut.

Main preparation chamber

This LEED uses an analog controller found in a movable rack next to the chamber. Ensure that both the connectors are firmly plugged into the LEED unit.

Filament current	1.95 A (=0.01mA I_emission, 3.3uA I_o)
Wehnhelt	-6 V
L1/3 @ 50eV	22 V
L2 @ 50eV	11 V
L1/3 @ 250eV	89 V
L2 @ 250eV	28 V
Screen HV	6-7kV

With any luck the L1/3 and L2 offset/gain knobs will be something sensible already, but example values are listed above in case you get totally lost and need to start again. Expect to need to slightly adjust L1/3 and L2 to optimize focus.
There is no shutter on this LEED
You will need to approach the LEED as far as it will go in order to get a decent image. Don’t forget to retract it before moving the manipulator away!

‘Prep top’

This LEED uses a digital LPS300-D controller found inside the glass-cabinet racks.

Filament current	2.5-2.6 A
Wehnhelt	0 V
Focus @ 120eV	144 V
Grid 2&3 @ 120eV	84 V
Screen HV	3.5kV

There a shutter on this LEED. It must be closed before you fully retract the LEED
You will need to approach the LEED as far as it will go in order to get a decent image. Don’t forget to retract it before moving the manipulator away!
Power supply operation: Push power on, then push in the beam energy knob. It will go to standby. Press the ‘press for menu’ button and select ‘STANDARD’ mode from this list. To make the filament and screen voltages ramp up, press the corresponding red ‘on/off’ buttons.