Development Of The Data Acquisition System For TopMetal2-Pixel Detector

PLAC(Pixel Laboratory At CCNU) has completed the design, tape out, test and application of two pixel sensors:MIC1 and TopMetall. The third pixel detector chip TopMetal2-is in the testing phase now, the basic principle of TopMetal2-is collecting charges through the exposed metal on the top layer of the chip, and then convert the charges into electrical signals for output. The content of this paper is to develop a high performance" data acquisition system, which is used to capture and readout analog signals in test and application of TopMetal2-.Currently, DAQ systems used in high-energy nuclear physics experiments and commercial used data acquisition cards are not suitable to small experiment, detector chip testing application, separately due to the complicated structure, large volume, low data read rate and the high cost, waste of resources and other characteristics. In view of this, this paper developed a low cost, high speed, high precision, scalable data acquisition system for chip’s test and application use. This DAQ system uses Xilinx Kintex-7 Series FPGA in scalable hardware unit as the logic controller, control a 4 channels,125MSPS,16 bits ADC chip to convert analog signals into digital form, coding in 8b/10b form and 4 channels become two 5Gbps data links to transmission, and then cache to 512MB DDR3 SDRAM memory, the Ethernet will transfer data to PC for storage and analysis under the control of MicroBlaze and PC.DAQ system contains of hardware circuits, control logic firmware, system software. Hardware circuit which contains of the front-end adjusting board, ADC sampling board and FPGA based main control board is responsible for signal conditioning, analog to digital conversion, data storage and transmission; control logic firmware use JESD204B to encoding and scrambling, use MIG to transmission, storage and readout data, use TEMAC to initial ethernet link for commands and data transmission; software system contains of MicroBlaze control software and PC analysis software, control software get data from the DDR3 memory and transfer through the Ethernet interface to PC for off-line analysis; DAQ has already been used in some TopMetal2-test and application use, and performde very well, showes that data acquisition system work stability in 125MSPS sampling rate,16 bits sampling precision and 5Gbps single channel data rate.