Design of the FPGA-based gigabit serial link for PandaX-III prototype TPC

Background:PandaX-III is aimed to search for neutrinoless double beta decay of 136Xe at China Jinping Underground Laboratory.To test various design features of PandaX-III detector,a prototype TPC with 20 kg Xe containing inside is built.Purpose:Front-end boards installed inside the waterproof vessel integrate charge of Micromegas signal,digitize signal waveform and send data packet to back-end board.Frontend boards receive synchronous information(global clock,global trigger,etc.),as well as command messages from back-end board.In order to satisfy the requirement of high data throughput and multiple types of synchronous data transmission,we propose an optical fiber link to communicate between front-end board and back-end board.Methods:Communication of serial transmission is performed using FPGA-based gigabit transceiver with a 1 Gbit/s point-to-point speed.A dedicated user-defined protocol is implemented for various kinds of data transmission.Results:To validate the performance of this link,bit error rate and eye diagram were tested.Preliminary joint test with detector was conducted in Shanghai.All test results showed sufficient data bandwidth and stable performance.Conclusion:To satisfy the requirement for data transmission between front-end board and back-end board in PandaX-III TPC detector readout,an FPGA-based gigabit serial link is designed and tested.This design shows good performance and will be applied to the R&D of PandaX-III TPC.