Mirror Assemblies M1 And M2; Grating Assembly; Beam Splitter Assembly; Photo Diodes Assemblies - Agilent Technologies InfinityLab LC Series User Manual

1 Introduction to the Variable Wavelength Detector
Optical System Overview

Mirror Assemblies M1 and M2

The instrument contains two spherical mirrors (M1 and M2). The beam
adjustable is vertically and horizontally. Both mirrors are identical.

Grating Assembly

The grating separates the light beam into all its component wavelengths and
reflects the light onto mirror #2.
The stepper motor reference position is determined by a plate fitted onto the
motor shaft, interrupting the beam of a photo sensor. The wavelength calibration
of the grating is done at the zero order light position and at 656 nm, which is the
emission line of the deuterium lamp.

Beam Splitter Assembly

The beam splitter splits the light beam. One part goes directly to the sample
diode. The other part of the light beam goes to the reference diode.

Photo Diodes Assemblies

Two photo diode assemblies are installed in the optical unit. The sample diode
assembly is located on the left side of the optical unit. The reference diode
assembly is located in the front of the optical unit.

Photo Diode ADC (analog-to-digital converter)

The photo diode current is directly converted to digital data direct photo current
digitalization. The data is transferred to the detector main board . The photo
diode ADC boards are located close to the photo diodes.
Agilent InfinityLab LC Series VWD User Manual 17