electron multiplier

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun An electronic component used in photomultipliers, particle detectors, and electron microscopes, in which single electrons may produce a large current by inducing secondary emission of electrons when they strike an anode.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a vacuum tube that amplifies a flow of electrons