A photosensor includes a vacuum tube having an inner space in which a photoelectron moves, a photocathode unit positioned at an upper portion of the vacuum tube to convert incident light incident from an outside into a photoelectron, a scintillator unit to react with the photoelectron to generate scintillation light, and a photomultiplier to convert the scintillation light into a photoelectron, and multiply the converted photoelectron to generate an electrical signal.

A photosensor includes a vacuum tube having an inner space in which a photoelectron moves, a photocathode unit positioned at an upper portion of the vacuum tube to convert incident light incident from an outside into a photoelectron, a scintillator unit to react with the photoelectron to generate scintillation light, and a photomultiplier to convert the scintillation light into a photoelectron, and multiply the converted photoelectron to generate an electrical signal.