I said 'band disappearing phenomena during exp.' and repaired degasser in peristic pump, the plot is good. In normal, degasser works continuously but it replays run/off/run/off before repairing. so vacuum is On off on off on off...then It cannot delete injected air.
(before repair pump)
(after repair pump... oh it has drift)
I am so happy because repairing pump reduced trouble, shcu as band disappearing and peak by air.