Sampling FEE and Trigger-less DAQ for the J-PET Scanner

TL;DR

This paper introduces a novel trigger-less data acquisition system for the J-PET scanner, enabling continuous high-speed data streaming and online event processing using FPGA-based modules.

Contribution

It presents a complete DAQ system with a trigger-less, continuous readout mode and a dedicated FPGA-based central controller for real-time data processing.

Findings

Achieved up to 8 Gbps data streaming capacity.

Implemented a novel FPGA-based signal discrimination method.

Ensured preservation of most data for high-level analysis.

Abstract

In this paper, we present a complete Data Acquisition System (DAQ) together with the readout mechanisms for the J-PET tomography scanner. In general detector readout chain is constructed out of Front-End Electronics (FEE), measurement devices like Time-to-Digital or Analog-to-Digital Converters (TDCs or ADCs), data collectors and storage. We have developed a system capable for maintaining continuous readout of digitized data without preliminary selection. Such operation mode results in up to 8 Gbps data stream, therefore it is required to introduce a dedicated module for online event building and feature extraction. The Central Controller Module, equipped with Xilinx Zynq SoC and 16 optical transceivers serves as such true real time computing facility. Our solution for the continuous data recording (trigger-less) is a novel approach in such detector systems and assures that most of the information is preserved on the storage for further, high-level processing. Signal discrimination applies an unique method of using LVDS buffers located in the FPGA fabric.