Agilent Technologies 1220 Infinity II LC User Manual page 121

8
Detector Description
Agilent 1220 Infinity II LC Diode Array Detector (DAD)
deuterium lamp by means of a special rear-access lamp design which allows
both light sources to be optically combined and share a common axis to the
source lens. The achromat (source lens) forms a single, focused beam of light
through the flow cell. Each cell room and lamp are separated by a quartz
window which can be cleaned or replaced. In the spectrograph, light is being
dispersed onto the diode array by a holographic grating. This allows
simultaneous access to all wavelength information.
Figure 36 Optical System of the Detector
Lamps
The light source for the UV-wavelength range is a deuterium lamp with a
shine-through aperture. As a result of plasma discharge in low-pressure
deuterium gas, the lamp emits light over the 190 nm to approximately 800 nm
wavelength range. The light source for the visible and SWNIR wavelength
range is a low noise tungsten lamp. This lamp emits light over the wavelength
range 470 – 950 nm.
Achromat
The achromat receives the light from both lamps and focuses it so that the
(Source Lens)
beam passes through the flow cell.
Holmium Oxide
The holmium oxide filter is electromechanically actuated. During the holmium
Filter
filter test it moves into the light path.
1220 Infinity II LC System User Manual 121