84
85-102113-00:1
Variable slit
The slit is located on a wheel that is controlled by the Star or
Galaxie Workstation. Slit widths corresponding to 1, 2, 4, 8 and
16 nm can be set. Use the narrower slits for measurement of
compounds with fine structure in the UV. Alternatively, the slit
can be opened to 8 or 16 nm when the maximum amount of light
is needed on each diode to minimize noise.
The slit setting is independent of the wavelength sampling setting
in the Workstation drivers. You can set the slit to a large number
but then take every 2
nd
, 4
th
8
th
or 16
th
wavelength.
Grating
A grating is used to disperse the light of incidence into a
continuous spectrum. It provides an approximate linear
dispersion and resolution across the entire UV-Vis spectrum.
Diffraction grating details
Grating size:
25 x 25 mm
Blaze angle:
2.1° (UV)
Blaze wavelength:
250 nm (UV-Vis)
Reciprocal dispersion: 30 nm/mm (UV-Vis)
Lines per mm:
300 lines/mm (UV-Vis)
Photodiode array
The photodiode array is a 1024 element array with a stray light
rejection filter on its window. The light from mirrors N4 and N5 is
reflected onto the array and signals are created on each of the
elements. Depending on the sampling interval, the array is
sampled and the data is stored in the instrument. The array is
aligned at the factory and any calibration must be performed by a
qualified Varian Customer Service Representative.
