Phosphor screens are used as readout devices for Open MCP detectors when imaging of the output signal is required.

They convert the cascade of electrons from the MCP detector into photons.

A phosphor screen is typically a glass window coated with a layer of an inorganic luminescent compound, also called "phosphor". The phosphor can be coated with an aluminum layer to further reflect the photons in the proper direction and thus increase the photon emission of the screen.