Calibration and Auxiliary Unit for INO’s ICAL Data Acquisition System

Magnetised iron calorimeter is a detector to study atmospheric neutrinos, proposed by the India based Neutrino Observatory. It will be built using 30 k Resistive Plate Chambers interleaved between iron plates. The neutrino interaction within the detector creates Muon tracks. The position information and TOF w.r.t trigger arrival of an interaction in RPC is recorded locally in each of participating DAQ nodes. CAU is a common interface between all ICAL subsystems for control, calibration and time synchronization. CAU caters global service signals over various electrical path length as per geographical position of RPC. The Global trigger delay offset at each RPC is computed by measuring the round path delay using calibration signals to translate local TOF w.r.t a global reference.