tecan infinite 200 - Light Source System Fluorescence Intensity

5. Optical System
2008-07 Instructions for Use for infinite® 200 No. 30017581 Rev. No. 1.4 67
5.1.1 Light Source System Fluorescence Intensity
Fluorescence applications usually require a specific range of excitation
wavelengths. Additionally, pulsed excitation light may be required (Time Resolved
Fluorescence [TRF]).
The
infinite
®
M200 light source system is built from the following components:
• Flash Lamp
• Condensing Optics
• Filter Wheel
• Excitation Double Monochromator
• Fiber Optic Bundle
• Flash lamp Monitor
Flash Lamp
The infinite
®
M200 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 a few
microseconds. The flash frequency is 40 Hz.
The
infinite
®
M200 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 from fused silica focus the flash light onto the entrance slit
of the excitation monochromator.
Filter Wheel
A filter wheel is located between the condenser and the excitation
monochromator. The filter wheel contains wavelength specific optical filters,
which are necessary to block undesired diffraction orders produced by the optical
gratings. The filters are set automatically.
Excitation Double Monochromator
In both fluorescence and absorbance applications, the Excitation Double
Monochromator is used to select any desired wavelengths from the flash lamp
spectrum in the range from 230 nm to 600 nm (standard version) or
230 to 850 nm (spectrally enhanced version) for fluorescence intensity and from
230 nm to 1000 nm for absorbance applications.
Fluorescence emission spectra in many cases do not depend on the exact
excitation wavelength. For a maximum total fluorescence signal; therefore, rather
broad excitation bandwidth may be used. The bandwidth of the
infinite
®
M200
monochromator system is < 9 nm for wavelengths > 315 nm and < 5 nm for
wavelengths ≤ 315 nm.
For a more detailed description of how a monochromator works see below.