Gamma Ray Array Detector Trigger Sub-System

TL;DR

The paper presents the design and implementation of a trigger subsystem for the Gamma Ray Array Detector (GRAD) using FPGAs and PXI interface, enabling prompt event selection and data transmission for gamma-ray experiments.

Contribution

It introduces a FPGA-based trigger subsystem for GRAD that processes signals from 1024 scintillators and transmits trigger data efficiently to the host computer.

Findings

Reliable and efficient performance in gamma-ray experiments.

Capable of making prompt L1 trigger decisions.

Supports off-line analysis with transmitted trigger data.

Abstract

Gamma Ray Array Detector (GRAD) is one of External Target Facility (ETF) subsystems at the Heavy Ion Research Facility at Lanzhou. The trigger subsystem of the GRAD has been developed based on Field Programmable Gate Array (FPGAs) and PXI interface. The GRAD trigger subsystem makes prompt L1 trigger decisions to select valid events. These decisions are made by processing the hit signals from 1024 CsI scintillators of the GRAD. According to the physical requirements, the GRAD trigger subsystem generates 12-bit trigger signals that are passed to the ETF global trigger system. In addition, the GRAD trigger subsystem generates trigger data that are packed and transmitted to the host computer via PXI bus for off-line analysis. The trigger processing is implemented in the front-end electronics and one FPGA of the trigger module. The logic of PXI transmission and reconfiguration is implemented in the other FPGA of the trigger module. The reliable and efficient performance in the Gamma-ray experiments demonstrates that the GRAD trigger subsystem is capable to satisfy the physical requirements.