The Image Dissector

Author: J.B. Hoag

A different form of pickup tube for television is known as an image dissector and is shown in Fig. 21 N.

Fig. 21 N. An image dissector with an electron multiplier. Used as a television pick-up tube

An image of a distant object is projected on a photo-surface. Electrons emitted from different small areas of this surface are brought in succession to an opening in a multiplier tube by means of deflecting coils (not shown in the figure). In the multiplier, they strike a first-stage sensitive surface where they cause the emission of, say, two or three secondary electrons per incident primary. These pass either to the collecting ring (see Fig. 21 N) or to the back side of the "scanning aperture" to produce an additional number of electrons by the secondary process.