Device description and operating principle
SPECORD
®
Design of subassemblies
4.2.2 Spectrometer system and photometer section
Sample compartment
Concave grating
Filter wheel
Plane mirror
Beam splitter
Quartz-coated
toric mirrors
Entrance
slit
Exit
slit
D E lamp
2
Halogen lamp
Swivel mirror
Detector
Detector
Cavity for
Cavity for
turbid samples
turbid samples
Cell
Cell
Toric illuminating mirror on SPECORD 200/205/210
or premonochromator grating on SPECORD 250
Fig. 4-4
Optical diagram of SPECORD
®
The spectrometer system with the optical elements illustrated above – filter wheel,
concave grating and slit assembly – works as monochromator.
The filter wheel contains the following filters:
4 color glass filters
Used to suppress unwanted radiation in the monochromator.
Holmium filter
Standard for the automatic recalibration of wavelengths.
2 blank positions
For the passage of non-dispersed light.
Block position
Needed for the generation of measured data.
The entrance and exit slits of the spectrometer system are mounted to the slit carrier.
Depending on the device model, the slits allow the following spectral slit widths:
SPECORD
®
200
1, 2, 4 nm
SPECORD
®
205
1.4 nm
SPECORD
®
210 / 250
0.5, 1, 2, 4 nm.
The imaging grating disperses the incident light and spreads it out into a spectrum.
Computer-controlled stepper motors drive the filter wheel, the slit carrier and the linear
actuator for moving the grating. Because of the little number of moving parts used in the
spectrometer system, the SPECORD
®
ensures a high reliability of its optical parameters.
In the photometer section, the mirror system divides the beam coming from the
monochromator into sample and reference beam. The imaging mirrors shape the beam
to the cross-sections needed in the sample compartment.
Spectrometer system and photometer section are protected against dust and reagents
by a cover. However, corrosive reagents or strongly evaporating liquids should be
inserted in the sample compartment only in stoppered cells.
Page 16
SPECORD
®
200/205/210/250 User's Manual – Edition 04/2005
Analytik Jena AG
