What component in an image intensifier tube determines the amount of magnification in the virtual image?

The component in an image intensifier tube that determines the amount of magnification in the virtual image is the electrostatic lens. This component plays a crucial role in manipulating the path of the electrons that have been emitted from the photocathode when exposed to light. By adjusting the strength and configuration of the electrostatic fields created by the lenses, the system is able to focus and magnify the image formed from the incoming light.

Electrostatic lenses work by generating an electric potential that influences the trajectory of charged particles, allowing for precise control over the image size and quality. When the electrostatic lens strength is varied, it can effectively increase or decrease the magnification of the virtual image on the output screen.

In contrast, the other components mentioned do not directly influence image magnification in the same manner. The focusing cup is involved in directing electrons but does not affect magnification; the magnifying lens would be associated with the output display rather than the intensification process; and the accelerating anode primarily serves to speed up the electrons towards the output phosphor, contributing to image brightness but not directly to the magnification. Thus, the electrostatic lens is pivotal in determining how significantly the image is magnified within the intensifier tube.