Development of a high resolution PXI based data acquisition system for electron momentum spectrometer

A high resolution PXI based data acquisition system is developed for a new electron momentum spectrometer constructed in the University of Science and Technology of China (USTC). This system concludes the detection of two outgoing electrons and the detection of ion, which is for more research on collision dynamics. This system mainly consists of a 9-channels time digitization module and a 6-channels charge digitization module, which are assembled in 6U PXI chassis. Related amplifiers are placed near the spectrometer. The measurement of charge involves charge sensitive preamplifier and the technology of digital peak detection. With the preamplifier constructed by discrete devices and charge digitization module, the accuracy of charge measurement can reach up to about 0.6%.Using the technology of TDC implemented in a field-programmable gate arrays (FPGA) from Xilinx Vertex IV family, the average bin size of time measurement can reach up to about 48ps, while the standard deviation is less than 30ps.