PerkinElmer Lambda 25, User Manual

Page: 39 / 116

Lambda 25, 35, 45 User’s Guide
38
Optical System of the Lambda 25, 35, 45
The Lambda 25, 35, 45 UV/Vis Spectrometers features an all-reflecting optical
system. The optical components are coated with silica for durability. A holographic
grating is used in the monochromator.
The optical system is depicted schematically in Figure 6.
The monochromator is a holographic concave grating with 1053 lines/mm in
the center.
Two radiation sources, a deuterium lamp and a halogen lamp, cover the working
wavelength range of the spectrometer.
For operation in the visible (Vis) range, mirror M1 reflects the radiation from the
halogen lamp onto source mirror M2. At the same time M1 blocks the radiation
from the deuterium lamp.
NOTE: In the Lambda 45, M2 is substituted by a pre-monochromator grating, increasing
the straylight performance of the instrument.
For operation in the ultraviolet (UV) range, mirror M1 is raised to permit radiation
from the deuterium lamp to strike source mirror M2.
Source change is automatic during monochromator slewing.
Radiation from the source lamp is reflected from source mirror M2 through an
optical filter on the filter wheel assembly.
A stepping motor drives the filter wheel to be in sychronization with the
monochromator.
Depending on the wavelength being produced, the appropriate optical filter is
located in the beam path to prefilter the radiation before it enters the
monochromator.
Filter change is automatic during monochromator slewing.
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com