The mechanism of Pt films to suppress the electron emission of grid in TWTs

Pt films were deposited onto molybdenum grids by ion‐beam‐assisted deposition (IBAD) method. Electron‐emission characteristics of molybdenum, with and without Pt films, contaminated by active electron‐emission substances (Ba and BaO) were measured by analogous diode method. X‐ray diffraction (XRD) and combined thermogravimetry/differential thermal analysis/mass spectrometry (TG‐DTA‐MS) were used to study the reaction between Pt and BaO in simulation experiments. The results showed that the emission current from an Mo grid coated with a Pt film is much less than that from Mo grid without a film, and the mechanism for electron emission suppression of the molybdenum grid coated with Pt films was discussed (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)