Plasma cleaner Increasing pressure in vacuum

We have a plasma cleaner, in order for the plasma to be created there has to be around 200-300 mtorr.


As soon as we turn the plasma, the mtorr instantly goes up but the vacuum line is still active.


The question is: What is the plasma in the chamber doing to make the pressure increase?


If this is the wrong section of stacked exchange can someone redirect me to the right section?


