Cold Cathode Ionization Vacuum Gauge

The televac 7b cold cathode gauge also called a penning ionization gauge or cold cathode ionization gauge has a measurement range from 10 7 torr up to 10 3 torr.

Cold cathode ionization vacuum gauge.

This vacuum gauge makes indirect absolute pressure measurements by ionizing gas in the presence of a magnetic field. In the cold cathode gauge ccg ionization is caused by a circulating electron plasma trapped in crossed electric and magnetic fields. The gauge is based on a triode configuration similar to that of a conventional hot cathode ionization gauge but instead uses a cold emission source based on cnts. This causes the electron with a charge e to acquire a kinetic energy ve.

A cathode may be considered cold if it emits more electrons than can be supplied by thermionic emission alone. It is often heated to its operating. They used a screen printing method to produce the cathode and found that the ratio of the ionization current to the cnt cathode current changes according to the pressure in the chamber. A cold cathode pressure gauge ionizes the rest gas in the system and uses the ion current as a measure of the pressure.

All ion gauge measurements are seriously affected by gas composition. In the hot cathode type a column of gas is introduced into which a potential difference v is applied with free electron in the space. All these problems can be nullified by vacuum measurement using cold cathode ionization gauge. The cold cathode type ionization gauge is used to replace the hot cathode type as it produces errors at very high temperatures of the cathode.

To overcome this problem the electrodes must be roperly treated before use. Pressure measurement part 5f cold cathode onization hot cathode ionization gauge https youtu be 4uoipuopfii. A cold cathode does not necessarily operate at a low temperature. Cold cathode ionization gauge ionization gauges which operate with a cold cathode discharge are called cold cathode or penning vacuum gauges.

Ionization gauge is a device that is used to measure vacuum. In both cases the electrical current resulting from the collection of the positive ions created inside the gauge is used as an indirect measure of gas density and pressure. It is used in gas discharge lamps such as neon lamps discharge tubes and some types of vacuum tube. A cold cathode is a cathode that is not electrically heated by a filament.

The other type of cathode is a hot cathode which is heated by electric current passing through a filament.