The Design Of A DAQ System For A GEM Flat-panel Detector

GEM Detector is a new kind of micro-pattern gas detector, and has great prospect in particle physics experiment and low energy X-ray imaging system. A good readout method is one of the key issue in its application. We are investigating the pixel readout of GEM detector with an array of filed effect transistors (FETs) using PCB technology. This readout method has advantages of simple manufacture, flexible parameters, low cost and can also provide us primary data for the future readout method based on ASIC technology or TFT. We have finished the functional verification for the detector and now we are developing a triple GEM based on the FET switch array.In order to finish this test mission for the GEM detector based on the FET switch array, as a part of the detector system, this paper designed a multi-channel real-time imaging data acquisition system. The aim is to implement real-time imaging observation for the detector signal. High-performance charge-voltage conversion chips and high-speed multi-channel A/D chips are used in the design. In addition, lots of state-of-art technologies, like FPGA, MCU, data acquisition based on network and LabVIEW etc, are used in the design.The system has 64 channels totally and 16 channels are used for testing the existing system. The imaging experiment with X-ray generator is done. The result shows that the effective A/D conversion result is greater than 12 bit. When working under the conditions of 16 channels, the system can accomplish 30 frame-per-second real-time imaging. The INL for the system is less than 1.33%.