Method and apparatus for preventing energy leakage from electrical transmission lines

A method for preventing energy leakage from a partially closed electrical transmission line connected to an energy source and located in an ambient environment, comprising:

• (a) injecting gas with a gas pressure into the transmission line;
• (b) connecting a conduit to the transmission line to allow gas to pass between the transmission line and the ambient environment with a flow rate;
• and
• (c) shutting down the energy source when the flow rate falls outside a predetermined flow rate threshold.

Apparatus for preventing energy leakage from a partially closed microwave waveguide connecting a microwave source to a probe in a nuclear magnetic resonance measuring system and located in an ambient environment, comprising:

• a coupler inserted into the waveguide between the microwave source and the probe;
• a gas source that injects gas with a gas pressure into the waveguide via the coupler;
• a conduit exhaust connected to the interior of the waveguide via the coupler that allows gas to pass between the waveguide and the ambient environment with a flow rate;
• and
• a first monitor that shuts down the microwave source when the flow rate falls outside a predetermined flow rate threshold.