Used with a [[scintillation]] crystal to make up a [[scintillation counter]]. The flash of light produced in the phosphor of a [[radiation]] [[detector]] strikes the sensitive surface of a photocathode in the photomultiplier, causing the emission of a number of primary electrons. These electrons are drawn to an anode maintained at a higher [[potential]], and a number of secondary electrons are emitted for each impinging electron. The secondary electrons are drawn to a second anode maintained at a higher potential than the first. whereupon additional multiplication occurs. This process is repeated in about ten stages until the initial current has been multiplied about a millionfold. The amplitude of the output of the photomultiplier is proportional to the intensity of the scintillation in the phosphor. See also [[scintillation counter]].

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