Data Acquisition System for a KL Experiment at J-Parc

We present the proposed Data Acquisition (DAQ) system for KOTO, a KL→π0νν experiment at J-Parc, Japan. It comprises two distinctive blocks: a 14(12)-bit, 125 (500) MHz ADC module for reading the approximately 4000 frontend channels; and a digital Trigger module able to provide a detector-wise synchronous energy sum. A Master Clock and Trigger Supervisor Module, with fans out of control signals to the whole system, completes the DAQ Architecture. The front-end readout board amplifies analog pulses from 16 photomultipliers and passes them through a 10-pole shaper before digitization. Data are then processed locally with field programmable gate arrays (FPGAs) to determine real-time energy values for the system Trigger Supervisor. The ADC module is provided with a pipeline, up to 4us long, which stores the acquisitions, awaiting the system trigger pulse. After a trigger, data are packed and buffered on on-board memories for readout via the VME32/64 backplane. The full design and preliminary test results will be described.