Baking and degassing in ultra-high vacuum system (1)

    In the vacuum technology, the term "baking" refers to heating the vacuum system or a part of the system to bake for a period of time during the operation of the vacuum system. During the baking stage, the gas decomposed by the material in the system is removed by a vacuum pump, and the end After baking, it is lowered to room temperature, thereby shortening the pumping time and speeding up to the specified vacuum. In addition, high-temperature baking can also remove contaminants such as grease on the surface of the parts.

    Regardless of whether it is a metal or glass system, the material in the system is not degassed. To obtain an ultra-high vacuum of 10^-6Pa or more at room temperature, it takes days or even weeks to continuously pump air to reach it. In order to shorten the operation time for obtaining ultra-high vacuum, the simplest and most effective method is to "bake" the container to degas. In addition, ion bombardment degassing, light degassing and radiation degassing can also be used to reduce the outgassing rate of materials. .

    Ion bombardment degassing is mostly used for the degassing of vacuum gauges, small vacuum vessels or workpieces. The measuring gauges in the system should also be degassed by ion bombardment before measurement to reduce the measurement error caused by the outgassing of the gauges. However, light degassing and radiation degassing are not only ineffective, but also restricted by various conditions. Except for some special devices, they are rarely used.

(Huiputech)