微结构气体探测器多通道高速读出系统研制

Development of Multi-channel High Speed Readout System for MPGD

本文设计并实测了用于多通道微结构气体探测器信号读出的512通道电子学系统。该系统以Spartan-6FPGA作为控制和数据处理核心,使用4通道ADC芯片对4片APV25芯片的输出信号进行同步模数转换,经千兆以太网发送命令和传输数据,计算机端则以双线程分别接收和发送数据。实测输入电容低于200pF时,系统噪声低于2 000e,有效电荷输入范围为±20fC,12fC以下时线性良好。经长时间测试,系统稳定可靠,千兆网数据传输速率可达940 Mb/s。单片APV25工作时,连续触发率可达APV25上限285kHz,4片时则为134kHz。在实际应用于GEM探测器α射线成像实验中取得了较好的成像结果。

A 512-channel signal readout system for the multi-channel micropattern gas detector was designed and tested.In this system,a Spartan-6 FPGA was used as the controller and processor.A 4-channel ADC was employed to convert analog signals output to digital signals by 4 APV25s synchronously.The data and commands between FPGA and computer were transmitted by gigabit Ethernet.Two threads were used for data sending and receiving separately at the computer end.The test result shows that the noise of the system is lower than 2 000 e when the input capacitance is smaller than 200 pF.The effective range of charge input is±20 fC and the linearity is very good below 12 fC.Long time tests show that the system is stable with the speed of Ethernet reaching 940 Mb/s.The continuous trigger rate can reach the upper limit of APV25(285 kHz)for 1 APV25 and 134 kHz for 4 APV25s.Good results were obtained in the imaging experiment of GEM detector withαray and this system.