An evacuated metal tube in which electrons pass through a series of small gaps (usually)
in the form of cavity resonators in the high frequency range) so arranged and spaced
that, at a specific excitation frequency, the stream of electrons on passing through
successive gaps gains additional energy from the electric field in each gap.
PAC, 1982, 54, 1533
(Glossary of terms used in nuclear analytical chemistry (Provisional))
on page 1545
IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by
A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997).
XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic,
J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8. https://doi.org/10.1351/goldbook