The concept of an ACEX® cost-effective first level surface detector trigger in the Pierre Auger Observatory

The paper describes the new design of the first level trigger for the surface array in the Pierre Auger Observatory. The previous design was tested in a small test segment called Engineering Array (EA). It confirmed full functionality and reliability of the PLD approach. However, because of the high price of the chips available at that time, a new cost-effective design was developed. Altera® offered cost-effective family, which allows reducing the total budget of the electronics without compromise in the functionality. The here described concept of a splitting of data processing into two sub-channels implemented into the parallel working chips, the chips synchronization and the automatization of internal processing management, together with the fully pipelined AHDL code became the framework for the further implementation in the environmental condition of the Argentinian pampa.