Electron Gun Filament

Introduction

A small amount of tungsten is used as heating material for high-temperature furnace, the heaters of electron tubes and rib reinforcement of composites. Most of them are used as the filament for incandescent lamps and halogen lamps and gas discharge lamp electrodes. As a gas discharge lamp electrodes, in order to reduce work function of electron, tungsten or tungsten rods shall be added 0.5% to 3% of thorium which called thorium tungsten wire. The properties of electron gun filament include its small size, non-sagging, good breaking resistance. On the one hand, it has a nice corrosion resistance. On the other hand, the electron gun filament has a long life for plating as well as the high thermal conductivity.

Classifications of Electron Gun Filament

Electron gun filament mainly consists of filament, cathode and grid configuration which can be divided into six types: mosquito coils, pull-type, U-shaped, U-shaped with folding tails, half-moon and straight shape.

Classifications	Specifications	Pictures
Mosquito Coil: this shape of the electron gun filament is similar to the shape of mosquito coil, therefore, it can be named as Mosquito Coil. And the Mosquito Coil can be divided into the following specifications.	0.55mm
	0.65mm
	0.80mm
Pull-type: Pull-type is also known as the cavity type of Mosquito Coil.	0.80mm
U-shaped: this kind of electron gun filament is similar to the shape of the letter U.	0.80mm
U-shaped with folding tails: the tails of the electron gun has a curved.	0.80mm
Half Moon: the shape of this type is the shape of a half moon.	0.80mm
Straight shape	0.80mm

Applications of Electron Gun Filament

1. Electron gun filament can be used for filament cathode tube emission. The electron gun filament can be applied to the filament cathode tube emission, under bombardment on kV high voltage conditions, electron gun filament can emitting a large number of electron by heating the filament and the cathode.

2. Electron gun filament can be applied in vacuum coating. A vacuum coating is a kind of technology, which can produce the thin film material by physical method. The electron beam heating has a higher flux density than that of the electric heating. What’s more, the electron beam can evaporate the high melting point materials. The kinetic energy of evaporating particles of the electron beam tungsten filament is large, and it benefits to obtain the membranous layer with a good bonding densification.

Actually, electron gun tungsten filament has extensive application in many fields. But people should know the correct way to use it, or its properties would be decreased.

Electron Gun Filament and Cathode

The cathode is the most important part of the electron gun filament whose quality directly determine on the quality of the electron gun filament. Cathode of electron gun filament means refers to the pole that gains electrons which would produce reduction reactions. Under the same emission intensity conditions, if the work function of materials is lower, then it can greatly reduce the temperature of the electron gun filament, so that it would be better to maintain the use of the electron gun filament. If you want to extend the life time of the electron gun filament, you need a higher melting point and a smaller evaporation rate cathode materials.