NanoESCA beamline description

Monochromator

The beamline monochromator uses the Variable Line Space (VLS) plane grating architecture. This solutions allows a large energy range can be covered with a relatively small change in the resolving power. Only two gratings are used to cover the energy range from 50 eV to 1000 eV. This is achieved by coupling the rotation of the grating with preceding plain mirror. The first grating has 200 l/mm and covers the energy range from 50 to 250 eV, while the second grating (400 l/mm) covers the range from 200 to 1000 eV. The calculated resolving power for the two VLS plane gratings is reported on the left hand side of the figure below. The full line is for the 200 l/mm grating and the dotted one for the 400 l/mm grating. The graph shows the measured spectrum of the nitrogen 1s to 1π* absorption from which we deduce a resolving power of 4000 at 400.8 eV, in agreement with the calculations.

Last Updated on Tuesday, 10 January 2012 17:35