FPGA Based Time Calibration Trigger System for the GRAPES-3 Experiment
摘要
The GRAPES-3 experiment contains several types of detectors namely plastic scintillators, proportional counters, and NaI (Tl) crystal detectors which are coupled with multiple independent data acquisition systems. At present, the GRAPES-3 operates 19 independent data acquisition (DAQ) systems. Multiple type detectors record different secondary components in the cosmic ray shower to study various physics phenomena including cosmic ray composition, multi-TeV gamma rays, and terrestrial gamma ray flashes produced by thunderstorms. It is necessary to collate the data with a common time stamp. In order to provide an easier hardware solution, an FPGA-based time calibration trigger (TCT) system has been designed which generates a precise handle among various DAQ systems. The TCT has been tested by implementing it for the trigger-less muon data acquisition (TMDAQ) system. The TMDAQ is based on the concept of making measurements from 118 channels by a single board in an independent fashion, for the generation of a user-desired trigger which is the core concept of TMDAQ. It is a necessity to collate the data collected from any of the above boards with precision. The accomplishment of the above is done by implementing the TCT system for the 16 boards. We will present the hardware details, its impact, and observations along with future plans.