A new dispenser cathode with dual-layer

The emission and surface characteristics of the dispenser cathode coated with Os-W alloy and that coated with Os-W/Re are studied and compared. The dispenser cathode coated with Os-W/Re has applied in electron gun measurement system for making measurement of higher emission current and life test. It is found that the dispenser cathode coated with Os-W/Re has higher current density than that coated only with Os-W alloy. In electron gun the dispenser cathode coated with Os-W/Re has pulse current density of 30 A/cm/sup 2/ and life of more than 800 hours.