What component of the image intensifier is characterized as flat?

The output phosphor is characterized as flat because it is designed to provide a uniform, high-quality image output in the imaging system. The output phosphor converts the electrons released by the photocathode into light, producing the final image that is viewed or recorded. This component is typically flat to facilitate even light distribution and to optimize the capture of the electron stream from the channel electron multiplier, ensuring that the entire area of the image is utilized effectively without distortion or variation in brightness across the image.

In contrast, the input phosphor is often curved, and the photocathode follows the shape of the input phosphor to enhance the efficiency of light collection. The channel electron multiplier, which amplifies the number of electrons without altering their spatial distribution, does not have a flat surface; its design is focused on the amplification process rather than image output. This flat structure of the output phosphor is essential for maintaining image clarity and quality in fluoroscopic procedures.