A system comprising: - a radiation body comprising a radiation exit window , wherein the radiation body is configured to receive radiation that at least comprises UV radiation, and wherein the radiation exit window is capable of allowing at least part of the radiation to pass to the exterior of the radiation body ; - a radiation arrangement configured to provide the radiation, comprising at least one radiation source including at least one UV radiation source configured to emit UV radiation , wherein at least one radiation source of the radiation arrangement is configured to emit polarized radiation ; - a detector arrangement configured to detect at least one of intensity of polarized radiation of the same polarization orientation as the polarized radiation emitted by the at least one radiation source and intensity of polarized radiation of orthogonal polarization orientation; and - a controller arrangement , functionally coupled to the radiation arrangement and the detector arrangement , configured to set a normal state of the at least one UV radiation source in which the at least one UV radiation source provides the UV radiation with an intensity at an operational level as a default, and to put the at least one UV radiation source from the default state to an adapted state in which the at least one UV radiation source provides the UV radiation with an intensity at a level that is reduced relative to the operational level after occurrence of a disturbance incident involving a change of the at least one of intensity of polarized radiation of the same polarization orientation as the polarized radiation emitted by the at least one radiation source and intensity of polarized radiation of orthogonal polarization orientation detected by the detector arrangement . - a radiation body comprising a radiation exit window , wherein the radiation body is configured to receive radiation that at least comprises UV radiation, and wherein the radiation exit window is capable of allowing at least part of the radiation to pass to the exterior of the radiation body ; - a radiation arrangement configured to provide the radiation, comprising at least one radiation source including at least one UV radiation source configured to emit UV radiation , wherein at least one radiation source of the radiation arrangement is configured to emit polarized radiation ; - a detector arrangement configured to detect at least one of intensity of polarized radiation of the same polarization orientation as the polarized radiation emitted by the at least one radiation source and intensity of polarized radiation of orthogonal polarization orientation; and - a controller arrangement , functionally coupled to the radiation arrangement and the detector arrangement , configured to set a normal state of the at least one UV radiation source in which the at least one UV radiation source provides the UV radiation with an intensity at an operational level as a default, and to put the at least one UV radiation source from the default state to an adapted state in which the at least one UV radiation source provides the UV radiation with an intensity at a level that is reduced relative to the operational level after occurrence of a disturbance incident involving a change of the at least one of intensity of polarized radiation of the same polarization orientation as the polarized radiation emitted by the at least one radiation source and intensity of polarized radiation of orthogonal polarization orientation detected by the detector arrangement . <EOS>