Radiation sensor including a detection assembly and a chopper assembly, which are mechanically coupled to delimit a main cavity; and wherein the chopper assembly includes: a suspended movable structure, which extends in the main cavity; and an actuation structure, which is electrically controllable to cause a change of position of the suspended movable structure. The detection unit includes a detection structure, which faces the main cavity and includes a number of detection devices. The suspended movable structure includes a first shield of conductive material, which shields the detection devices from the radiation, the shielding of the detection devices being a function of the position of the suspended movable structure.