5. Optical System
2008-07 Instructions for Use for infinite® 200 No. 30017581 Rev. No. 1.4 73
5.2.1 Light Source System
Flash light enters the optical system by being focused through an orifice
containing the filter. This opening acts as a color specific light source.
The
infinite
®
F200 light source system is built from the following components:
• Flash lamp
• Condensing Optics
• Excitation Filters
• Flash lamp Monitor
Flash lamp
The infinite
®
F200 utilizes a high energy Xenon arc discharge lamp (Flash lamp).
The flash sparks across a small gap between two electrodes. The lamp bulb
contains a high pressure Xenon atmosphere. The flash decays within some
microseconds.
The flash frequency is 40 Hz.
The
infinite
®
F200 uses the Flash lamp for fluorescence and for absorbance
measurements, although pulsed illumination is a must only for TRF. The main
benefits of this singular kind of lamp are:
1. High intensity from the deep UV to the near IR
2. Very long lifetime
3. Many applications - only one kind of lamp
4. No warm up time required
Condenser
Condenser type optics focuses the light through the entrance orifice to the
fluorescence optical system.
Band Pass Filter
In both fluorescence and absorbance applications, optical filters of band pass
type are necessary to select the useful wavelengths from the Flash lamp
spectrum. Filters are mounted in removable slides.
Excitation Filter
In many cases, fluorescence emission spectra do not depend on the exact
excitation wavelength. Therefore, for a maximum total fluorescence signal,
relatively broad excitation band pass filters (10 – 40 nm) may be used.
The spot diameter for the
infinite
®
F200 is about 2 mm for the top optics and
2 mm for the bottom optics.
Flash Monitor
The light energy of single flashes may fluctuate slightly. To take these variations
into account, a silicon photodiode monitors the energy of every single flash.
Fluorescence measurement results are compensated correspondingly.
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