Abstract
Indication of an ionization gauge is frequently fluctuated abnormal due to the deposit of oil vapour.
In this report I treated the effect of constructive material and of the temperature of envelope.The clean-up of the surface of constructive material depends merely on the temperature of material and is prominent at about 330°C, and if the temperature of envelope is kept about at 100°C, the abnormal out-gassing phenomenon will decrease.
