Introduction . A beam vacuum chamber interacts with the beam in many ways: among these is wakefield generation. In general, the wakefield impedance of a chamber depends on the material used, its surface characteristics and the chamber geometry [ 1 ]. Non-Evaporable Getter (NEG) was first invented at CERN in the 1990s [ 2 ] and are now widely employed in many accelerators and various projects such as LHC, MAX-IV, ESRF, ELETTRA, Soleil, APS upgrade, ALS upgrade, etc. However, its impac...