The phosphor screen converts accelerated electrons into photons. Typical conversion factors of the used phosphor screens are between 20 and 200 photons per electron, depending on the phosphor type and the kinetic energy of the electrons, i.e. the acceleration voltage.

What does the center of a phosphor screen represent?

What does the signal in the middle of the screen represent? The phosphor screen detects charged particles (such as alpha particles) and it glows momentarily at the positions where the particles impact the screen.

What is the function of phosphor in CRT?

CRTs are used to produce images. The phosphors in a CRT's screen are the materials that directly produce the photons generated by the CRT. These phosphors are struck by incoming electrons from the electron gun, absorb energy, and then re-emit some or all of that energy in the form of light.