GridPix: An integrated readout system for gaseous detectors with a pixel chip as anode

GridPix is a gas-filled detector in which a Micro Pattern Gas Detector is combined with a CMOS pixel chip. In a next step, a procedure to construct a grid onto a Si wafer, using chip production technology (‘wafer post-processing’), has been developed. Protection against discharges are under study, and an ageing test of a Micromegas chamber has been carried out, after verifying the chamber's proportionality at a very high dose rate. The GridPix detector can be applied as X-ray imaging device. With a drift gap of only 1 mm, GridPix could be well applied as radiation hard, low power, (and therefore) low-mass vertex (track) detector. New developments in CMOS pixel chips, forming the core of the detector, are presented.