Design Of PXIe-based Multi-channel Data Acquisition System Of Soft X-ray Camera

To solve the great problem of the declining of energy sources such as oil,natural gas and coal,domestic and foreign scientists conduct deeply research in the field of controlled thermonuclear fusion for decades,and ITER is designed.The goal is to build a large Tokamak device with controlled ignition and self-sustaining combustion to cause nuclear fusion and to get great energy,and lay the foundation for the construction and application of commercial demonstration reactors.To study the physical processes of plasma instability state,sawtooth characteristics,impurity radiation,and etc.in the nuclear fusion reaction,and to provide reference data for plasma control,a soft X-ray camera is installed inside equatorial port 12 of the ITER device.Which is used to detect the soft X-ray radiation distribution in the radial direction of the plasma,the energy range is 1 keV ~ 10 keV.The soft X-ray camera is mainly composed of detector,pre-amplifier,mid-amplifier,data acquisition,CODAC central control system,and etc.The light signal of soft X-ray can be converted into current signal which range is 10 nA ~ 10 μA by the detector.After pre-amplifying,mid-amplifying,and signal conditioning,the signal reception is completed by the data acquisition module.The signal voltage amplitude at this time can reach-10 V ~ 10 V.The soft X-ray have the features of wide dynamic range of signal amplitude and vulnerable to electromagnetic field interference,multi-channel array parallel processing is required,PXIe-based multi-channel data acquisition system of soft X-ray camera is proposed in this dissertation.In order to realize the high-speed transmission characteristics of PXIe,Xilinx's FPGA chip Kintex-7-325T-900-2 is used as the main controller.In the hardware circuit structure,the multi-level processing of the analog signal is realized by the signal conditioning circuit,the analog-to-digital conversion is performed by 5 MSPS sampling rate and 16-bit serial ADC chip LTC2325,and the FPGA system development is performed,in which digital signal storage,serial-to-parallel conversion and PXIe bus transmission are realized.The data communication between the computer and the multi-channel data acquisition system is realized by LabVIEW-based upper computer software,and the function verification of the system is completed.The hardware and software components of this system and the PXIe bus transmission principle are discussed in this dissertation,and multi-channel soft X-ray camera dataacquisition and processing can be realized.The experimental results show that this system can acquire signals within 1 MHz and the resolution of the it can reach to 0.122 mV during normal operation.