baking

"Baking" is to heat vacuum chambers under a vacuum state, such as the FEG chamber, the inside walls of the microscope column and the specimen stage, to obtain a high vacuum in a TEM. Baking accelerates degas from the vacuum chambers and decreases subsequent outgas. When a TEM equipped with an FEG is used, baking of the FEG chamber is performed for more than 40 h at a high temperature of ～300 ℃ so that stable operation and long lifetime (operating time) of the FEG are achieved and also discharge damage to the FEG is decreased. When the column and stage which use O-rings are baked, the baking is carried out for about 3 days at ～60 ℃ because these parts cannot be baked at a high temperature.