Scintillation Counters and Photomultiplier Tubes
Incoming photons expel electrons from the metallic
surface of the photocathode via the photoelectric effect.
The effect was discovered by
Heinrich Hertz in 1887 and
explained by Albert Einstein
According to Einstein's theory,
light is composed of discrete
particles of energy, or quanta,
called PHOTONS. When photons with enough energy
strike the photocathode, they liberate electrons that have
a kinetic energy equal to the energy of the photons less
the “work function” (the energy required to free the
electrons from a particular material).
Einstein received the Nobel Prize for his 1905 paper
explaining the photoelectric effect. What were the other
two famous Einstein papers from 1905?
Theory of special relativity
Explanation of Brownian motion