Design Of Multi-channel Data Acquisition System For Beam Monitor

Silicon pixel sensor has the advantages of small volume, high position resolution, fast readout and other advantages and is becoming an important research field in nuclear detection technology, To this end, The PLAC developed the TopMetal pixel sensor chip.We take that can be used in tumor therapy research and development task distribution of the beam monitor,and declared Chinese National Natural Science Foundation. Beam monitor is composed of TopMetal and its multi channel data acquisition system,the multi channel data acquisition system is the research content of this paper.According to the design principle, the data acquisition system with high performance FPGA as the control core, the control of multi channel,12 bit high speed ADC acquisition TopMetal each pixel detection information, DDR2memory buffer to the large capacity of USB, and finally transferred to the storage and analysis of PC machine. The control instruction at PC by RS232 serial port is sent to the FPGA.In this paper, the main research work includes:1, the hardware design:This platform includes TopMetal driver board, ADC sampling module board. TopMetal driver board to achieve the desired TopMetal chip with high stability, high pixel clock bias voltage and low noise of the TopMetal output. ADC sampling module board to complete 8 channel,12 bit ADC synchronous sampling and using 8 differential data transmission 3.8Gbps.2, the firmware design:in order to achieve flexible control logic, the logic of high-speed data transmission viafirmware and low-speed control command is designed separately. The global control register device is a key operation to control the data transmission channel of ADC, USB and DDR2.3,the software design:the PC has developed is corresponding to the FPGA firmware settings and control software, which can be used to obtain PC scripting system to control the whole system.Finally, we carried out the module level and system level testing of the system, and using ROOT to analyze the test data. The results show that, the data acquisition system of 3.8Gbps in the system throughput can still achieve error free transmission, good to meet the beam monitor the data acquisition system requirements.