Novel pixel detectors for X-ray astronomy and other applications

Abstract

Following previous work in particle physics, the MPI Semiconductor Laboratory has been founded with the purpose of developing novel semiconductor detectors for particle physics and X-ray astronomy. A short description of the already successfully concluded development of pn-CCDs for focal imaging in X-ray astronomy (XMM/Newton X-ray Observatory) is given and the much more demanding requirements in a future X-ray astronomy experiment (XEUS) are discussed. A new type of pixel detector is proposed which will be capable to meet these requirements. It is based on the “DEPleted-Field Effect Transistor (DEPFET)” principle. The device operated on a fully depleted silicon wafer allows an internal charge amplification directly above the position where the signal conversion takes place. A very low gate capacitance of the DEPMOS transistor leads to low noise amplification. In contrast to CCDs, neither transfer loss nor “out-of-time events” can occur in a DEPFET-array. A very interesting feature is the possibility of repeated non-destructive readout which can be used for noise reduction even for the low-frequency (1/ f) noise. This type of detector will also have its applications in linear collider experiments.