Research On Digital Multi-channel Time-sharing Pulse Height Analysis Electronics System Based On PXIE

With the increasing demand for energy from industrial development and the relatively low utilization of clean energy,fusion nuclear energy,as a new type of clean energy,has attracted widespread attention from various countries in the world.During the research and utilization of fusion nuclear energy,how to ensure long-term safe and stable operation requires a set of diagnostic systems to monitor various states of fusion operation,including plasma temperature measurement,plasma density measurement,plasma configuration measurement,and magnetic measurement,spectrum measurement,radiation measurement,etc.Among them,the hard X-ray diagnostic system measures the hard X-ray parameters radiated during the operation of the fusion plasma,so as to study the physical characteristics such as fast electronic behavior,lower-hybrid wave?LHW?deposition and driving effect.The core electronic measurement technology for this diagnosis is the multi-channel pulse height analysis technology,which is widely used in nuclear energy spectrometers.With the rapid development of digitization and semiconductor technology,nuclear measurement technology is constantly updated.The multi-channel pulse height analyzer has gradually developed from analog to digital.The digital multi-channel pulse amplitude analyzer not only has a simpler hardware circuit structure,but also its accuracy and sensitivity have gradually improved,which has become a research hotspot at home and abroad.Experimental Advanced Superconducting Tokamak?EAST?is the most advanced nuclear fusion research platform in China,and it also plays an important role in the field of fusion research worldwide.With the continuous development of nuclear fusion research,in the hard X-ray diagnosis of the EAST device,the accuracy,time resolution,number of channels,and data transmission protocols of energy spectrum measurement cannot keep up with the requirements of high-parameter plasma operation.In addition,the general products on the market can not directly meet the demand,so the system needs to be upgraded and upgraded.This article selects?Research on Digital Multi-channel and Time-Division Pulse Height Analysis Electronics System Based on PXIE?as the research topic,mainly to study the software and hardware of multi-channel time-division pulse amplitude analysis system?MTPHA?.The performance of the system was verified in the electronic laboratory and EAST experimental environment.Among them,the core component of the system is the MTPHA function board uses a 16-bit high-precision ADC chip AD9269 as an analog-to-digital conversion module,and uses an FPGA chip of type XC7K325T-FFG900 in the Kintex-7 series produced by Xilinx of the United States as an spectrum data processing and control module.Based on the open-source PCIe code provided by Xilinx,the spectrum data of the PXIE bus communication protocol is transmitted.The maximum number of channel addresses of 4096 and the minimum time resolution of 2 ms.The hardware circuits of the MTPHA board mainly include signal limiting circuits,signal switching circuits,analog signal amplification circuits,single-ended to differential circuits,ADC analog-to-digital conversion circuits,FPGA configuration circuits,Flash storage circuits,PXIE interface circuits,and power circuits.The hardware description language?Verilog HDL?is used to design the internal logic functions of FPGA on VIVADO 2016.3 software,including sampling process for analog-to-digital conversion,pulse identification,peak-finding processing,energy spectrum storage and transmission and other algorithms.MTPHA uploads the processed energy spectrum data to the upper computer LABVIEW software through the PXIE communication protocol,and uses LABVIEW software to process,display and store the energy spectrum data in real time.The PXIE bus communication protocol is implemented by combining the hardware code in the FPGA with LABVIEW software in the host.Because LABVIEW software uses a graphical programming language,it is easy to use,which greatly shortens the development cycle of the system and reduces research and development costs.The MTPHA performance has been tested in the lab with pulse generator,¹⁵²Eu isotope radiation source and tested in plasma discharge of EAST.It is found in the lab that the full width at half maxima?FWHM?of MTPHA is no more than 2 channels,and the linear correlation coefficient R of pulse height and channel address is 1,indicating that the board has a very high energy resolution and linearity.In addition,in the EAST experiment,MTPHA function board can work well and produce experimental data consistent with other diagnostics,further indicating that MTPHA is stable and reliable,which is helpful for studying the fast electronic behavior of EAST and future CFETRs,and LHW deposition and driving effect.At the same time,other general nuclear energy spectrum measurement occasions can be promoted and applied.