Dynode (source code)
= Dynode
A <dynode> is an electrode that emits <secondary electrons> when struck by an incoming <electron>. A <photomultiplier> arranges successive dynodes at increasing potentials so that photoelectrons are accelerated and multiplied through a cascade.
If the mean multiplication factor per stage is $\delta$ and there are $n$ comparable stages, the idealized mean gain is $\delta^n$. Fluctuations in secondary emission contribute to output noise. Excessive current can disturb the electrode voltages or create space-charge effects, so gain <calibration> and linearity need experimental checks.
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