Toward the implementation of the trigger scheme for the ICAL detector of India-based Neutrino Observatory

The India-based Neutrino Observatory (INO) collaboration has proposed to build a 50 kton magnetized Iron Calorimeter (ICAL) detector with the primary goal to study neutrino oscillations, employing Resistive Plate Chambers (RPCs) as active detector elements. The architecture of the ICAL trigger scheme has already been validated and the results are reported in a previous paper. As a first step toward the implementation of the trigger scheme, we have designed an FPGA-based trigger module and deployed it in the prototype detector. In this paper, the design features of the trigger module are described and some evaluation results are presented. A design for the implementation of the proposed trigger scheme for a larger prototype of the ICAL detector, known as the ICAL Engineering Module, is also discussed.