Understanding Dynode Multiplication in Scintillation Detectors

[m-i-t-o]

Hi all,my question is on dynodes. For ex: in scintillation detector we ususally say that a visible photon when incident on photocathode,undergoes photoelectric effect.But what the process occurring on dynodes when this photoelectron incident on it.
Electrons are multiplying successively as moving from one dynode to other.What you called such a process,this is not photo electric effect! as instead of photon electron is incidenting on material.
Please help

 

[malawi_glenn]

The photoelectric effect is just creating the first electrons, then these electrons are accelerated towards metal plates and will blast out electrons from it, and these will be accelerated to another metal piece etc.

The electrons are IONIZING the atoms in the metal, ionization due to collisions you might call it. (c.f collision ionization in hot and dense astrophysical gases etc.)