= Electron multiplier
{tag=Electronic amplifier}
{wiki}
An <electron multiplier> amplifies a signal by accelerating incoming <electrons> into surfaces that emit additional <secondary electrons>. Repeating this process at successive stages produces a measurable charge packet from a small initial signal.
A <photomultiplier> adds a photosensitive input that converts incident light into a <photoelectron>; its <dynodes> then perform multiplication. In a simple equal-stage model with mean secondary yield $\delta$, $m$ stages give mean gain $\delta^m$. The output fluctuates because emission is stochastic, and saturation can invalidate constant gain. Multiplication increases the signal scale but cannot recreate input events that were never detected.
Back to article page
