Optical Attenuators For Use With Optional Ingaas Detector - PerkinElmer SPECTRUM TWO N User Manual

Getting Started with Spectrum Software . 57
Optical Attenuators for Use with Optional
InGaAs Detector
The high detectivity of InGaAs (indium gallium arsenide) detectors makes them prone to
saturation, a condition that results in non-linear detector responses. Limiting the optical
throughput to the detector is used to prevent detector saturation and can be accomplished
through the use of optical attenuators. For spectrometers equipped with the temperature-
stabilized, high-performance InGaAs detector, four optical attenuators are supplied having
nominal percent transmittance values of 0.5%, 1%, 2%, and 4% T. For information
Appendix 5: Calibration Procedure for Optical
regarding calibration of optical attenuator see
Attenuators
. The 1% beam attenuator is the default attenuator, all final factory tests are
performed with this attenuator in place. The optical attenuators are inserted into a slot
located on the detector side sample compartment window, as shown in Figure 34.
Figure 34 Positioning of optical attenuator in sample compartment of Spectrum
Two N FT-NIR spectrometer.
In the event of detector saturation a warning message will appear in the Spectrum 10
software on the bottom right-hand corner as shown in Figure 35.
Figure 35 Warning message displayed in Spectrum 10 software under conditions
of detector overload