Chapter 1: Introduction 35
Figure 1-5 Dichroic filter types in octagon array
The steering optics and filters mounted on the BD LSR II instrument are listed in
Table E-1 on page 154.
See Optical Filters on page 127 for a more detailed explanation of how filters
work in the BD LSR II flow cytometer.
Detectors
Light signals are generated as particles pass through the laser beam in a fluid
stream. When these optical signals reach a detector, electrical pulses are created
that are then processed by the electronics system.
There are two types of signal detectors in the BD LSR II flow cytometer: the
photodiode and the photomultiplier tubes, or PMTs (Figure 1-6 on page 36). A
photodiode is less sensitive to light signals than the PMTs. Therefore, a
photodiode is used to detect the stronger forward scatter signal. PMTs are used
to detect the weaker signals generated by side scatter and all fluorescence
channels. These signals are amplified by applying a voltage to the PMTs. As the
voltage is increased, the detector sensitivity increases, resulting in increased
longpass dichroic mirrors
bandpass filters
LSR2.book Page 35 Tuesday, April 25, 2006 3:34 PM
To Next Page
Loading...
