DIRAC v2: a DIgital Readout Asic for hadronic Calorimeter

DIRAC is a 64 channel mixed-signal readout integrated circuit designed for Micro-Pattern Gaseous Detectors (MICROMEGAS, Gas Electron Multiplier) or Resistive Plate Chambers. These detectors are foreseen as the active part of a digital hadronic calorimeter for a high energy physics experiment at the International Linear Collider. Physic requirements lead to a highly granular hadronic calorimeter with up to thirty million channels with probably only hit information (digital calorimeter). The DIRAC ASIC has been especially designed for these constraints. Each channel of the DIRAC chip is made of a 4 gains charge preamplifier, a DC-servo loop, 3 switched comparators and a digital memory, thus providing additional energy information for a hit. A bulk MICROMEGAS detector with embedded DIRAC v1 ASIC has been built. The tests of this assembly, both in laboratory with X-Rays and in a beam at CERN are presented, demonstrating the feasibility of a bulk MICROMEGAS detector with embedded electronics. The second version of the ASIC, with improved noise and additional functionalities, has been tested on bench and characterisation is detailed, and foreseen associated detectors are presented.