Selector™ Diffuse Reflectance Accessory
3
1. Introduction
Thank you for purchasing a Specac product.
Infrared radiant light when reflected from a solid surface can be either
diffuse, specular or both (total reflectance) in nature.
Diffuse reflectance is based upon the collection of radiation that has
been
diffusely scattered
from the sample. From illumination by
infrared radiation of a solid sample surface that can deemed non linear
or irregular (e.g. powdered, granular or fabric/textile type samples),
although there will be components of some specularly reflected light
from the surface, the majority of light to collect for measurement will be
diffusely scattered.
The Selector™ accessory P/N GS19000 uses an optimized off-axis
optics configuration which selectively collects and maximizes the
diffusely reflected components of light, whilst minimizing the specular
component. The off-axis design also allows for the expansion of use of
the Selector optics with alternative specialized baseplates such as the
Environmental Chamber (P/N GS19930).
The Selector™ accessory is provided with a range of sampling cups
for appropriate sample study which include a standard 11mm diameter
cup, a micro 4mm diameter cup and a tilted cup. The tilted cup can be
used for the collection of
total reflectance
(diffuse and specular
components of light) spectra, if desired. In addition, there are also
abrasive sample mounts for use with 12mm diabraze pads. The
diabraze material is rubbed against the surface of an intractable solid
to deposit a small amount of the solid on the abrasive pad surface. The
diabraze pad, on the sample mount, is then placed into the sampling
position post of the Selector™ accessory.
The design of Selector™ accessory for the arrangement and infrared
light beam passage sequence for its optical mirror components means
that it is a
beam direction dependant accessory
for correct
installation into a spectrometer system. A left to right or right to left
beam direction (source to detector) as it passes through the
