A gas turbine for power plant; the gas turbine having an axis and comprising: - a compressor sector for compressing ambient air, - a combustor sector for mixing and combusting the compressed air with at least a fuel; the combustor sector comprises at least a liner (7, 26) defining a combustion chamber (6, 21, 23) having an axial direction and a circumferential direction; - at least a turbine sector for expanding the combusted hot gas flow leaving the combustors and performing work on a rotor; - at least a damping device arranged outside the combustion chamber (6, 21, 23) and comprising a damping volume and a perforated plate configured for fluidly connecting the combustion chamber (6, 21, 23) to the damping volume for damping pressure fluctuations generated inside the combustion chamber (6, 21, 23); wherein the perforated plate is slanted shape so that the radial thickness of the perforated plate varies along the axial combustor direction and/or along the circumferential combustor direction; wherein the perforated plate comprises an inner face, an outer face and a plurality of channels extending from the inner face to the outer face; characterized in that the inner face is arranged on the outer surface for the combustor liner; the combustor liner comprises a plurality of holes at the channels for fluidly connecting the combustion chamber (6, 21, 23) to the damping volume; wherein the inner face is flat and parallel to the axial combustor direction, the outer face is inclined with respect to the axial combustor direction and or along the circumferential combustor direction so that the radial extent of the channels varies along the axial combustor direction and/or along the circumferential combustor direction. - a compressor sector for compressing ambient air, - a combustor sector for mixing and combusting the compressed air with at least a fuel; the combustor sector comprises at least a liner (7, 26) defining a combustion chamber (6, 21, 23) having an axial direction and a circumferential direction; - at least a turbine sector for expanding the combusted hot gas flow leaving the combustors and performing work on a rotor; - at least a damping device arranged outside the combustion chamber (6, 21, 23) and comprising a damping volume and a perforated plate configured for fluidly connecting the combustion chamber (6, 21, 23) to the damping volume for damping pressure fluctuations generated inside the combustion chamber (6, 21, 23); wherein the perforated plate is slanted shape so that the radial thickness of the perforated plate varies along the axial combustor direction and/or along the circumferential combustor direction; wherein the perforated plate comprises an inner face, an outer face and a plurality of channels extending from the inner face to the outer face; characterized in that the inner face is arranged on the outer surface for the combustor liner; the combustor liner comprises a plurality of holes at the channels for fluidly connecting the combustion chamber (6, 21, 23) to the damping volume; wherein the inner face is flat and parallel to the axial combustor direction, the outer face is inclined with respect to the axial combustor direction and or along the circumferential combustor direction so that the radial extent of the channels varies along the axial combustor direction and/or along the circumferential combustor direction.