Development of the MISTRAL & ASTRAL sensors for the upgrade of the Inner Tracking System of the ALICE experiment at LHC

A detector, equipped with 50 um thin CMOS Pixel Sensors (CPS), is being designed for the upgrade of the Inner Tracking System (ITS) of the ALICE experiment at LHC. Two CPS flavours, MISTRAL and ASTRAL, are being developed at IPHC aiming to meet the requirements of the ITS upgrade. The first is derived from the MIMOSA28 sensor designed for the STAR-PXL detector. The second, which integrates a discriminator in each pixel, improves the readout speed and power consumption. This paper will describe in details the sensor development and show some preliminary test results.