A radiation detector of the ΔE-E type is proposed. The detector is integrated in a chip of semiconductor material with a front surface and a back surface opposite the front surface, the detector having at least one detection cell arranged on the front surface for receiving a radiation to be evaluated, wherein the detector includes: a first region of a first type of conductivity extending into the chip from the front surface to a first depth; a second region of a second type of conductivity extending into the chip from the back surface to a second depth so as to reach the first region; and for each detection cell a third region of the second type of conductivity extending into the first region from the front surface to a third depth lower than the first depth and the second depth, a thin sensitive volume for absorbing energy from the radiation being defined by a junction between the first region and each third region, and a thick sensitive volume for absorbing further energy from the radiation being defined by a further junction between the first region and the second region. For each detection cell the detector further includes insulation means arranged around the third region and extending from the front surface into the first region to an insulation depth comprised between the first depth and the third depth.