First reticule size MAPS with digital output and integrated zero suppression for the EUDET-JRA1 beam telescope

A high resolution beam telescope, based on CMOS monolithic active pixel sensors (MAPS), is being developed within the EUDET collaboration. Mimosa26 is the first pixel sensor covering an active area of ∼224 mm2 with integrated zero suppression for this telescope. A single point resolution better than 4 μm is expected with a pixel pitch of 18.4 μm. The matrix is organised in 576 rows and 1152 columns. At the bottom of the pixel array, each column is connected to an offset compensated discriminator to perform the analogue to digital conversion. Digital data are then treated by a zero suppression circuit in order to send useful information. This architecture allows a fast readout frequency of ∼10 k frames/s. The paper concentrates on the details of the chip design and its main performances.