The working principle of the Silicon Drift Detector (SDD)

The working principle of the Silicon Drift Detector (SDD) is based on the concept of sideward depletion invented by Pavel Rehak and Emilio Gatti in 1983 [1]. It allows the depletion of a large volume of high-resistivity silicon material by a small anode receiving a minimum signal capacitance. By that, the SDD overcomes the major problem of a classical p-i-n diode detector where the input capacitance is direct proportional to the active area. Figure 1 shows a schematic view of the SDD in its standard configuration [2]: