Principle Of Operation - Hitachi CHROMASTER 5160 Instruction Manual

2.4 Principle of Operation

Aberration-free
concave grating G1
Detector S
Filter F
(O-54/UV-32)
Slit S1
Slit S2
Detector R
Flow cell
Half mirror
HM1
Condensing
mirror M2
Fig. 2-4 Optical Schematic of this UV-VIS Detector Unit
The light emitted from the light source (D
condensing mirror M1, passes through slit S1 and then is
dispersed by aberration-free concave grating G1.
Monochromatic light passing through exit slit S2 is condensed
again by condensing mirror M2.
The light beam is then divided with half-silvered mirror HM1.
One half-beam passes through the flow cell and arrives at
detector S. The other half-beam arrives at detector R.
The latter beam is used as a reference signal to compensate for
variations in the light source.
The beams arriving at detectors S and R are converted into
electrical signals and the S/R value undergoes logarithmic
conversion. The result is output as an absorbance-linear signal
to the data processor and recorder. For measurement at a
wavelength of 351 nm or longer in the D
(UV-32) is inserted in the optical path in order to cut off the
second-order diffraction light. For measurement at 601 nm or
longer in the W lamp mode, filter F (O-54) is inserted in the
optical path in order to cut off the second-order diffraction light.
2 - 5
W lamp
Condensing
mirror M1
D lamp
2
/W lamp) strikes
2
lamp mode, filter F
2
2.4