Amplification factor in IOTs with island building

In a triode type electron gun the amplification factor, mu, determines how the beam current varies with time for any given gun geometry and applied voltages. A simple triode low-mu formula has regularly been used to predict IOT behaviour however, it is incapable of addressing non-uniform cathode emission resulting from modern grid geometry and small cathode-grid distances. Consequently it is incapable of detailing meaningful emission behaviour or accurate prediction. A literature search identified few mu formulae suitable for IOT-type geometry. Results show excellent agreement between them but a significant departure from the often-used Maxwell or ldquolow-murdquo triode formula . The formulae should offer the ability to more accurately predict IOT performance characteristics.