Sodion S-13 tube detector

Sodium tube triode detectors designed by the American radio engineer Harold Donle are considered. An analysis of the operating principle of the sodium detector has been made. Donle's patent for the design of a sodium detector is presented. The first design of a sodium detector lamp, in which a container of liquid metal sodium was used as the anode, is presented in detail. The reasons for refusing further use of this detector lamp design are indicated. Attention is paid to the second improved version of the Sodion S-13 lamp detector using a small drop of sodium the size of a match head.