First results of DEPFET-based active-pixel-sensor prototypes for the XEUS wide-field imager

Abstract

The concept of an Active Pixel Sensor (APS) based on the integrated detector/amplifier structure DEPFET (DEpleted P-channel Field Effect Transistor) has been developed to cope with the challenging requirements of the XEUS Wide Field Imager. The DEPFET-APS combines high energy resolution, fast readout, and random accessible pixels allowing the application of flexible readout modes. First prototypes of DEPFET-based Active Pixel Sensors with a 64 x 64 pixel format and 75 μm x 75 μm pixel area have been produced at the MPI semiconductor laboratory. The APS is read out row by row, i.e. the pixel signals of one row are processed in parallel by a 64 channel CMOS amplifier/multiplexer chip of the CAMEX type. The addressing of one row of pixels for readout and reset is done by two control chips of the SWITCHER type fabricated in a high-voltage CMOS technology. The processing time for one row is of the order of a few micro-seconds. APS operation, the control and data acquisition system are described, and first experimental results are presented.