An attenuation apparatus, comprising: a grating, for receiving a radiation beam (Ba) and for directing at least a portion of the radiation beam (Ba) in a first direction in the form of a first reflected radiation beam and one or more first actuators operable to rotate the grating about a first axis to adjust a first grazing angle between the radiation beam (Ba) and a surface of the grating so as to vary an intensity of the first reflected radiation beam, the apparatus further comprising a reflective optic operable to receive the first reflected radiation beam and to direct at least a portion of the first reflected radiation beam in a second direction in a second reflected radiation beam (Ba0'); and one or more second actuators arranged to rotate the reflective optic about a second axis to adjust a second grazing angle between the first reflected radiation beam and a surface of the reflective optic so as to vary an intensity of the second reflected radiation beam (Ba0'), wherein the one or more first actuators are operable to translate the grating such that an attenuated radiation beam is directed from the attenuation apparatus in a fixed position and direction, or wherein the one or more second actuators are operable to translate the reflective optic such that an attenuated radiation beam is directed from the attenuation apparatus in a fixed position and direction, and wherein the rotation of the grating about the first axis and the rotation of the reflective optic about the second axis both cause an increase of the first grazing angle and the second grazing angle or both cause a decrease of the first grazing angle and the second grazing angle. a grating, for receiving a radiation beam (Ba) and for directing at least a portion of the radiation beam (Ba) in a first direction in the form of a first reflected radiation beam and one or more first actuators operable to rotate the grating about a first axis to adjust a first grazing angle between the radiation beam (Ba) and a surface of the grating so as to vary an intensity of the first reflected radiation beam, the apparatus further comprising a reflective optic operable to receive the first reflected radiation beam and to direct at least a portion of the first reflected radiation beam in a second direction in a second reflected radiation beam (Ba0'); and one or more second actuators arranged to rotate the reflective optic about a second axis to adjust a second grazing angle between the first reflected radiation beam and a surface of the reflective optic so as to vary an intensity of the second reflected radiation beam (Ba0'), wherein the one or more first actuators are operable to translate the grating such that an attenuated radiation beam is directed from the attenuation apparatus in a fixed position and direction, or wherein the one or more second actuators are operable to translate the reflective optic such that an attenuated radiation beam is directed from the attenuation apparatus in a fixed position and direction, and wherein the rotation of the grating about the first axis and the rotation of the reflective optic about the second axis both cause an increase of the first grazing angle and the second grazing angle or both cause a decrease of the first grazing angle and the second grazing angle.