A reliable and efficient detection system essentially needed in the depth profiling of radiotracers consisting of two large PIN-diode arrays has been constructed. The requirements put forward to the detector system and the ability of the PIN-diode array to meet these demands are discussed. A comparison to a conventionally used liquid scintillation detector is presented by measuring an as-implanted 31 Si profile in amorphous T21 ceramic by both apparatuses. (C) 2002 Elsevier Science B.V. All rights reserved.