DEPMOSFET Active Pixel Sensor Prototypes for the XEUS Wide Field Imager

Active pixel sensors (APS) based on the depleted P-channel MOSFET (DEPMOSFET) recently produced at the MPI semiconductor laboratory are a promising new type of sensor to cope with the advanced requirements of the XEUS wide field imager, a large area imaging and spectroscopy detector for X-ray astronomy. The DEPMOSFET APS combine high energy resolution, low power consumption and random accessibility of pixels providing for highly flexible readout modes with fast readout speed. In the first prototype production, several design variants of 64$,times ,$64 pixel DEPMOSFET matrices with a pixel size of 75$times ,$75$mu hbox m^2$have been realized. A data acquisition (DAQ) system for evaluation of sensor prototypes has been developed, which allows for a performance characterization of the different designs. For operation, DEPMOSFET device, front-end IC and control ICs are integrated onto a readout hybrid. Device readout is done row by row, addressing and resetting one single matrix row at a time and processing the signals with a 64 channel parallel CMOS amplifier/multiplexer IC of the charge amplifier multiplexer type applying 8-fold correlated double sampling. Addressing and resetting of the matrix rows is done by two control ICs of the SWITCHER type fabricated in a high voltage CMOS technology. A number of readout hybrids has been built, the characterization of the different devices in terms of noise, spectral resolution and charge collection efficiency is in progress. The most promising DEPMOSFET matrix design variants, the DAQ system and measured key performance parameters of the devices are presented.