PerkinElmer Spotlight 150, User Manual

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Overview of the Spotlight 150 . 31
IR optics in reflectance
IR optics in reflectance differs from viewing in reflectance as follows (Figure 10):
•
The toroid moves to send the beam to the Reflectance illuminator assembly dichroic
mirror, which sends it through the upper cassegrain.
• The beam is reflected off the sample and back through the other side of the cassegrain,
toward the remote aperture.
• The detector cassegrain focuses the beam on to the detector.
Figure 10 Path of the infrared beam for collecting IR spectra in reflectance
NOTE:
Figure 10, above, illustrates a Spotlight 150 with an MCT detector. Other detector
types may look different, but the optical arrangement is the same in all cases.
Dichroic mirror
Variable aperture
Reflectance
illuminator assembly
Upper cassegrain
Sample position
Lower cassegrain
Detector cassegrain
Detector
Source toroid