Development of indigenous silicon detector and readout electronics for forward electromagnetic calorimeter prototypes

ALICE is a high-energy physics experiment at the CERN Large Hadron Collider (LHC) in Geneva, to study the properties of quark-gluon plasma, formed in heavy-ion collisions. In the upgrade program, a new electromagnetic forward calorimeter (FOCAL) based on silicon and tungsten (Si+W) sampling configuration, has been proposed to address new physics objectives of ALICE experiment. The high luminosity environment of the LHC and the requirement of compact design for the FOCAL, put stringent requirements for the development of silicon detector and front-end electronics (FEE). The ALICE-India collaboration made the first proposal for the FOCAL in the year 2008, and initiated indigenous R&D activities for silicon detectors, FEE and instrumentation. As a result, large area (40 cm 2 ), segmented silicon pad sensors (6.3 cm x 6.3 cm with 36 pads) and two different FEE application-specific integrated circuits (ASICs), ANUSANSKAR and ANUINDRA respectively, were developed. Progressive FOCAL prototypes were built using these sensors and ASICs, which have undergone test beam validation in a phased manner achieving the desired calorimetric performances, in line with the GEANT-based performance simulations. Further, the results of the test beam experiments provided crucial inputs for achieving the technical specifications of the silicon detector and readout electronics for the final calorimeter. This manuscript presents, in a chronological order, India's indigenous FEE ASICs, sensor and instrumentation development and reports the subsequently improved readout methodology for the prototype FOCAL detector.