Table of Contents
Advertisement
External angle of deflection
The ratio of light on the two photodiode elements, which arises from a
positional change of an image cast onto the photodiode, is determined by the
external angle of deflection (φ), as shown in the figure below. The external
angle of deflection determines the magnitude of the shift (Δx) of a slit image
cast on the photodiode by the light beam.
The following figure illustrates the external angle of deflection and its
dependence on the difference in RIs (Δn) between the reference and sample
sides of the flow cell.
How refraction changes the external angle of deflection:
θ
Reference side
of flow cell
θ
Effect of refraction on the external angle of deflection
As the beam of light moves along the light path to the photodiode, it
encounters and is refracted by the air in the optics bench assembly, the fused
Y
n
φ
n
Y
n + Δn
Sample side
of flow cell
φ
n
October 13, 2014, 715003547 Rev. C
Operating principles
= Δx
21
Advertisement
Table of Contents
