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Imaging System Hardware
Emission filters are located in a sixteen-position filter wheel that is readily
accessible in the GenePix Autoloader 4200AL. Four positions in the filter
wheel are reserved for the standard emission filters (red, yellow, green,
blue) and are installed at the factory and are not accessible. The remaining
twelve positions are available to the user for custom filter installation (see
below). Additional filters can be obtained directly from Axon, or a custom
filter can be ordered directly through a optical filter company such as
Chroma Technology Corp. (Brattleboro, VT); Omega Optical Inc.
(Brattleboro, VT); or Semrock (Rochester, NY.) We recommend that you
use latex gloves or finger cots when handling filters to avoid getting
fingerprints on the optical surfaces.
If you decide to use different dye and/or filter combinations, it is important
to match the optical characteristics of filter, dye, and laser. The
transmission band of the filter should be centered as close as possible to the
emission peak of the chosen dye, and must be narrow enough to exclude
light from the laser, other dyes, etc., but not so narrow that too many
emission photons are excluded, otherwise sensitivity will be lost. We also
strongly recommend that a reject filter of OD 8 be employed to eliminate
laser excitation.
Installing Filters
Before installing filters, turn the scanner power off. To gain access to the
filter wheel, use the hex key to open the front access panel and gently pull
the filter wheel cassette out by the handle.
The filter wheel cassette is numbered and there is an access port on the top
of the cassette in which to install filters. There is an opening at the rear of
the cassette that allows you to rotate the filter. Choose a filter position by
moving the filter wheel so that the designed position is lined up with the
top access port. There is an arrow on the mounting ring of the filter that
indicates the propagation direction. The arrow on all filters obtained from
Axon Instruments indicate the propagation path
to the PMT detector
; thus
the arrow should be facing down (into the table) when installing a filter in
GenePix 4200AL User’s Guide, Copyright 2005 Axon Instruments / Molecular Devices Corp.
