MCS260B
CORNERSTONE 260B MONOCHROMATORS
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8 GETTING LIGHT INTO A MONOCHROMATOR
8.1 ACCEPTANCE PYRAMID
The figure below shows the optical path of the light input to the instrument. The monochromator
has an acceptance pyramid, often described by an F/#. The position and dimensions of the
internal optics determines the pyramid. The optical equivalent is a grating image located behind
the slit as shown below (Fig 23). Only light that passes through the slit in the direction of this
grating image is useful.
Always fill the acceptance pyramid of the instrument with light.
Figure 23: Acceptance Pyramid of Monochromator.
Figure 24:
Grating Correctly “Filled” with Light.
