Beamline and analyzer slits

Analyzer slit

Before starting the measurement select a proper analyzer slit (black knob on the analyzer).

Back side of the analyzer and black knob for slit selection. Current reading is 100.

Narrow slit: + better k-resolution perpendicular to the slit - more difficult to focus and less counts. Curved slit: + flat Fermi level and constant energy surfaces - makes a curved cut in k-space Straight slit: + makes a straight cut in k-space - curved Fermi level (energies need to be corrected programmatically).

We usually start with 400.

Table can be also found on the wall behind the monitors

850 = Fully open, only for pumping down!

Beamline exit slit

Beamline (BL) exit slit vertical width is controlled manually with a knob behind the electronics rack.

The BL slit knob. Reading is 13.95.

With a smaller slit you improve energy resolution, but get less counts.

Plateau area (~140um) is a good starting point.

BL exit slit calibration curve. Plateau area is around 12+-1.

Beamline resolution for a given BL exit slit and photon energy can be estimated using an Igor script provided below (beamline parameters correspond to 1^2):

Change only the 2 parameters on top.

39KB

Calculate_BL_Resolution_v1.pxp