Farnsworth Image Dissector

[peter scott]

Originally Posted by zenith2134

Can anyone elaborate on the theory of function for an image dissector? How does it differ from a vidicon/plumbicon type sensor?

The essential difference between the image dissector and the iconoscope and all more modern designs is that the image dissector signal output is only generated for the instant that the light was hitting the target coincident with the scanning beam. In other words a very brief instant.

In the iconoscope the signal output is the accumulation of photo electric charge from light acting on the target for the full duration of one frame.

This is why Farnsworth's tube was so insensitive relative to the iconoscope.

One attempt to improve it's sensitivity is shown in the tube under discussion here in that it has an electron multipler attached to the target. (The reason for all the connection pins.)

Peter