4. Optical System
32
Instructions for Use for INFINITE M1000 PRO No. 30064852 Rev. No. 1.0
2011-09
4.1.1
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 M1000 PRO
light source system is built from the following
components:
1. Flash
lamp
2. Condensing
optics
3. Order sorting filter wheel
4. Excitation double monochromator
5. Fiber optic bundle
6. Flash lamp monitor
Flash Lamp
The
INFINITE M1000 PRO
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
INFINITE M1000 PRO
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:
a) High intensity from the deep UV to the near IR
b) Very long lifetime
c) Many applications - only one kind of lamp
d) No warm up time required
Condenser
Condenser type optics from fused silica focus the flashlight onto the entrance slit
of the excitation monochromator.
Order Sorting 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 monochromator
is used to select any desired wavelengths from the flash lamp spectrum in the
range from 230 nm to 850 nm for fluorescence intensity and from 230 nm to
1000 nm for absorbance applications.
In many cases, fluorescence emission spectra do not depend on the exact
excitation wavelength; therefore, for maximum total fluorescence signal, a broad
excitation bandwidth should be used.
For measurements > 300 nm, the
bandwidth can be selected continuously from 5 nm to 20 nm in 1 nm steps.
For measurements
≤
300 nm, the bandwidth can be selected continuously
from 2.5 to 10 nm in 0.5 nm steps.
For a more detailed description of how a monochromator works, see below.
