  The development of an innovative position sensitive pixelated sensor to
detect and measure with high precision the coordinates of the ionizing
particles is proposed. The silicon avalanche pixel sensors (APiX) is based on
the vertical integration of avalanche pixels connected in pairs and operated in
coincidence in fully digital mode and with the processing electronics embedded
on the chip. The APiX sensor addresses the need to minimize the material budget
and related multiple scattering effects in tracking systems requiring a high
spatial resolution in the presence of a large occupancy. The expected operation
of the new sensor features: low noise, low power consumption and suitable
radiation tolerance. The APiX device provides on-chip digital information on
the position of the coordinate of the impinging charged particle and can be
seen as the building block of a modular system of pixelated arrays,
implementing a sparsified readout. The technological challenges are the 3D
integration of the device under CMOS processes and integration of processing
electronics.
