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Spectroscopy Applications

Absorbance, Transmittance and Reflectance

A generic absorbance/transmittance or reflectance measurement system consists of (see the Fig.):

  • A broadband light source
  • Filter wheel
  • Monochromator
  • Sample chamber or system (such as a fiber optic probe)
  • Detection system

A dual-beam configuration is recommended wherever possible for high-quality reproducible quantitative analysis. The following are some guidelines for absorbance, transmittance, and reflectance measurements:

1. Most chemical and filter applications require smaller monochromators, such as the Acton SpectraPro-150 or Acton SpectraPro-300i. Some applications with samples containing narrow features may require larger monochromators, such as the Acton SpectraPro-500i with 500 mm focal length.

2.
Consider the following when choosing a detector:

  • Total wavelength region required for the sample measurements
  • Expected level of sample absorption
  • Light source intensity over the entire wavelength region for the sample measurements

 
PMT's are normally required for UV measurements, while silicon detectors typically work well over the 400-1100nm range. InGaAs and other appropriate detectors are recommended for measurements above 800nm.




Choose from the following for more detailed application descriptions:


Recommended Products:

Acton Series Monochromators & Spectrographs
-  Positrak™ grating stabilization offers simple calibration
-  Optimized coatings for higher throughput
-  Interchangeable grating turrets with a wide selection of gratings


PIXIS CCD Cameras
-  Lifetime vacuum guarantee for worry-free operation
-  Deep cooling without the need for liquid circulators
-  Up to 1000 spectra/sec data acquisition

SPEC-10 CCD Cameras
-  Exclusive dual amplifier design offers high SNR or high dynamic range
-  Superior low light sensitivity through deeper cooling

PI-MAX ICCD Cameras
-  5MHz digitization provides up to 15 frames per second
-  500ps gating for ultra fast time resolution
-  Exclusive UNIGEN photocathode for highest sensitivity from deep UV to NIR

OMA V InGaAs Array Cameras
-  Excellent NIR sensitivity for demanding spectroscopy applications
-  Electronic shutter allows intergration times down to 20 µsec
-  1MHz digitization provides up to 1800 spectra/sec