In modern particle accelerators with ultra-low emittance,
the vacuum chambers are designed based on Non-Evaporable Getter
(NEG)-coated vacuum chambers. The thickness of the NEG coating plays
a critical role in the dynamic beam effects. So, in this paper, the
longitudinal and transverse impedance of a copper chamber coated
with a NEG are investigated, and the effects of the NEG thickness
over a wide range of frequencies have been studied. A good selection
of NEG layer thickness could minimize the coating effects on the
longitudinal and transverse beam impedance. The numerical results in
this work show that the beam dynamic effects could be minimal with
selecting a NEG coating thickness of about 1 μm.