We present a new class of Micro Pattern Gas Detectors in which a complete
integration between the gas amplification structure and a pixelized
read-out electronics has been reached.
We call this device the Gas Pixel Detector (GPD).
For this purpose we have developed and built two generations of an
Application-Specific Integrated Circuit (ASIC) in deep sub-micron
The CMOS chip has the top metal layer patterned in a matrix of
80Ám pitch hexagonal pixels used as charge collecting pads and directly
connected to the underneath electronics chain which has been realized
using the remaining five layers of the 0.35Ám VLSI technology.
In this way gas detectors performances approach solid state device
standards in terms of spatial resolution (~30Ám) and rate capibility
(a few MHz/mm2).
Results from tests on a first prototype of such detector with 2k pixels and
on its further implementation to 22k pixels are presented.
An application of this device for Astronomical X-Ray Polarimetry is discussed.