Keithley 2520INT, Quick Start Manual

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Model 2520INT Quick Start Guide Getting Started 2-5
Full beam collection
Full beam collection is important for optimum optical power measurement ( Figure 2-5 ).
The maximum acceptance angle of the sphere in the vertical direction is 45˚ half angle
(divergence) from the entrance port. The maximum acceptance angle of the sphere in the
horizontal direction is 25° half angle from the entrance port.
NOTE
Information provided is based on the sphere orientation shown in Figure 2-5.
Figure 2-5
Horizontal and vertical acceptance angle
NOTE
Distance for full acceptance at the maximum acceptance angles should not
exceed 3.1mm from input port.
Sphere
Input Port
DUT