What is the required potential difference to accelerate the electron stream in an image intensifier?

In an image intensifier, the required potential difference to effectively accelerate the electron stream is typically around 25 kilovolts. This voltage provides sufficient energy for the electrons generated from the photocathode to travel through the device and reach the anode, resulting in the amplification of the image.

The significance of using a potential difference in the kilovolt range is tied to the need for high energy levels to ensure that the electrons can overcome any potential barriers, such as space charge effects, and maintain a sufficient speed to contribute effectively to image formation. A potential difference of 25 kilovolts allows for a robust electron flow, maximizing the amount of light produced at the output phosphor of the image intensifier, ultimately leading to a clearer and more detailed image for the observer.

The other options present potential differences that are either insufficient or more commonly associated with other imaging modalities but do not align with the operational requirements of an image intensifier in fluoroscopy.