New Front end and trigger electronics for the ALPACA experiment

A new air-shower array experiment with high sensitivity for sub-PeV γ-rays is currently under construction in the Chacaltaya Plateau in Bolivia. This experiment, called ALPACA, will search in the southern sky for γ-ray sources using surface detectors and underground muon detectors to discriminate against the cosmic ray background. Beyond ALPACA, a future mega-square meter air shower array, Mega ALPACA is proposed to determine the acceleration limits in our Galaxy. Considering this, our goal is to design new front and trigger electronics which provide long-term stable operation, meanwhile being capable of processing the required number of channels. For the Front end electronics, we designed a system with high resolution and wide dynamic range. The circuit also digitizes the signal from the detectors and transfers the information to the rest of the system using FPGA. For the trigger electronics, we are designing an all-digital sum trigger, which selects events using the arithmetical sum of the number of detectors above a given threshold. To evaluate the performance, we developed a custom-made pulse generator capable of reproducing the timing characteristics of the air-shower experiment. In this paper, we will present the details of the design of both systems and the results as well as the performance evaluation to measure resolution and linearity. We also present the results of the testing of the modules done at the site of the ALPACA experiment in comparison with the DAQ electronics currently used in the array.