2012 Product Catalogue

Specac Product Catalogue 2012 | A-Z of IR
A-Z of IR
Selector
Specac’s versatile diffuse reflectance accessory,
featuring unique off-axis optics to fully minimize
unwanted specular reflectance, offers rapid FTIR
analysis of solids with minimal sample
preparation. The Selector can include an
Environmental Chamber, for extreme
temperature and pressure analyses, an
Autosampler, to automatically analyze up to 32
samples, and an X-Y stage, for sample mapping
of large or inhomogeneous samples.
Signal-to-Noise Ratio (SNR)
To determine the quality of a spectrum, or
spectrometer, the SNR is the ratio of the signal,
or intensity, of the spectrum to the noise at a
nearby point on the baseline.
Silicon
Element, atomic number 14, atomic weight
28.09, grayish metallic semiconductor.
A very hard, inert crystal with a refractive index of
3.42, Silicon is very useful for Far IR in the range
400 to 30cm -1 .
Single Beam Spectrum
The spectrum obtained after Fourier
Transforming an interferogram. The single beam
spectrum is a combination of the spectra of the
sample (if applicable), the instrument and the
environment.
Sirocco Gas Cell
Specac’s advanced transmission gas analysis
cell is a new concept in gas cell specification.
With an extensive array of standard features on
the base unit, personalized modifications can be
made from a range of precision engineered
options. A range of pathlength options allows
analysis at low pressures to be performed in the
longer cells, and pathlengths can be verified with
a laser alignment accessory.
Specacard
Mount for the transmission analysis, and storage,
of KBr pellets. Specacards can also be used,
with a magnetic film holder, for polymer films.
Specular Reflectance
The reflectance occurring when a beam of light
strikes a smooth, shiny surface, e.g. a mirror,
such that the angle of incidence equals the angle
of reflection. Specular reflectance can be used to
obtain Infrared spectra.
T
Transmission
A physical phenomenon where radiation passes
through a body.When producing a transmission
spectrum a proportion of the energy is absorbed
by the sample, while the remainder travels on to
the detector.
Transmission Sampling
The method of sampling whereby the Infrared
beam passes directly through the sample before
being detected, used in such accessories as the
Variable Temperature Cell holder, the Omni Cell
and the Sirocco Series Gas Cell. An appropriate
pathlength must be selected so as to avoid total
absorption of the Infrared.
Transmittance
Unit of measurement of the amount of radiation
transmitted by a sample. It is often the Y-axis of
Infrared spectra. Transmittance is not linearly
proportional to the concentration of the sample,
therefore spectra plotted with these units cannot
be used for Quantitative Analysis.
V
Variable Temperature Cell holder
Specac’s most advanced accessory for the
transmission analysis of liquids and solids at
temperatures from -190ºC to 250ºC. Choice of
window material allows this accessory to be
used in UV, Visible and Infrared regions. This
accessory can also be used for Fluorescence
and the Raman Technique.
W
Wavelength
One wavelength is the distance between two
identical points on two adjacent identical waves
in a beam.
Wavenumber
Wavenumber is defined as the reciprocal of the
wavelength expressed in cm. Units are cm -1 .
Wave numbers are normally the units along the
X-axis in Infrared spectra.
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