|
The OEM Division routinely
adapts its spectrographs to solid state and other detectors chosen by
the customer, as well as to customers' interface requirements.
Alternatively, we can supply the entire assembly, including the
detector, accessories, and electronics that best suits the
application. JY is a leading manufacturer of detector assemblies for
use in spectroscopy.
The OEM Division
specialises in sales to original equipment manufacturers and
government-funded projects. For one off spectroscopy detectors you
should visit the JY Optical Spectroscopy Pages.
CCDs (charge coupled devices)
These are two-dimensional
detector arrays built onto a silicon chip. The pixels are read out
sequentially. The device acts like an electronic reusable
photographic film - the pixels accumulate light intensity information
until they are read out. They are then ready for a new "exposure."
The main difference
between CCDs used in sensitive measurement applications, such as
spectroscopy, and those used in cameras and camcorders, is the
quality of the CCD required for the job. The most demanding
spectroscopic applications require CCDs that have very low pixel
noise, excellent uniformity of response, and high quantum efficiency
-- in some detectors down into the ultraviolet region. The available
response range is from 200 nm (with UV enhancement) to 1000 nm. Lower
cost, camera-quality CCDs can sometimes be used in less demanding applications.
In spectroscopy, the
two-dimensional capability is suited to multiple fiber optic inputs
as well as 2-dimensional solid state array detectors. The fibre
positions form one dimension and spectral wavelength the other
dimension; so that multiple spectra are obtained simultaneously. A
wide variety of detector sizes and pixel sizes are available.
For best signal-to-noise
ratios (SNR), detector cooling is recommended, which may be either TE
(thermoelectric) or LN (liquid nitrogen) cooling.
PDAs (photodiode arrays)
These are linear arrays of
photodiode detectors on a single strip of silicon. Frequently used in
moderate to high light level applications, PDAs are available as
single or double arrays. Double arrays are convenient for two-channel
instruments. PDAs may be used uncooled, or cooled to achieve lower
detector noise. They typically cost less than CCDs and have similar
spectral sensitivity in the range 200 nm to 1000 nm.
Infra-red (IR) detector arrays
For spectra in the NIR
region, from 1 to 2.5 microns wavelength, InGaAs detectors are
usually employed. We also offer spectrographs, monochromators, and
diffraction gratings for use in the NIR region.
|
•