When Methane is decomposed on the CRT Manufacturing Process

Vacuum surroundings in Cathode Ray Tubes (CRT) are very important factor for CRT lifetime, especially cathode & getter's. A getter is a very good vacuum pump; unfortunately, it cannot absorb an inert gas and hydrocarbons. There are only argon and helium in CRT after $1^{st}$ emission test because other active gases are absorbed by getter and methane is decomposed during CRT working. It is also very important to know exactly where and when methane is decomposed during the CRT manufacturing process, because methane is known to be harmful to cathode when its amount is high, and getter can't absorb the methane.