Development Of A New Control System For Pulse Neutron Generator

The neutron generator is a kind of equipment to produce neutron radiation,it consists of a neutron tube,a driving power supply and a control system.The neutron generator has the characteristics of high energy of neutron,good monochromaticity,stable and controllable output,safe use and the like,which has a wide range of applications in the field of material element analysis and oil logging.The neutron generator has two operating modes: DC and pulse.In the DC mode,the neutron generator is mostly used for neutron irradiation.In the pulse mode,the multichannel analyzer uses the trigger of synchronous pulse to separate the neutron gamma spectrum and facilitate the analysis of the physical elements.Neutrons produced by a neutron generator can have a variety of nuclear reactions,resulting in non elastic,capture,and slow onset gamma rays.In the latest international frontier research,these characteristics can be separated by pulse time sequence,which is conducive to the improvement of neutron multielement analysis accuracy,especially for online analysis technology applications.Therefore,in the actual process of material analysis,a single neutron spectrum can not meet the needs of the user.In order to obtain more information about the nuclear reaction in the neutron spectrum,it is necessary for the neutron generator to produce more complex timing pulses and corresponding synchronization pulses.In this paper,a new type of pulse neutron generator console is designed for the self targeted ceramic neutron tube of the autonomous intellectual property ZFD-1 type of Northeast Normal University.Based on the original DC / pulse mode,the console realized the separation of energy spectrum based on the single burst and compound pulse mode according to the difference of neutron burst time.In addition,the neutron generator will produce a large number of neutron radiation during normal operation,in order to ensure the safety of operators and users away from the test site to the neutron generator operation,but the operation personnel also need real-time monitoring of the neutron generator,the neutron generator joined the remote monitoring system.The hardware design,the main control circuit,with STM32 as the core of the power supply circuit,driving circuit and remote scaler neutron waveform monitoring circuit,realizes the data acquisition,DA output,Serial port and USB communication,drive power supply design,remote monitoring of synchronization pulse,neutron counting and other functions;A synchronous pulse timing circuit based on FPGA is designed,which realizes the three modes of pulse output of the console,and lays the hardware foundation for subsequent neutron gamma spectrum separation experiment.On the software side,the C program of STM32,the Verilog program design of FPGA and the synchronization of pulse neutron and multichannel analyzer are completed.On the host computer,regard LabVIEW platform as the core,designed the test interface and system control interface of each function module.Compared with the previous console communication protocol,the console has transplanted the FreeModbus protocol,which has strong reliability in the industrial field,and further enhances the fault tolerance of the system.The pulse neutron generator is designed in this paper the actual performance test results: storage current,ion source voltage,accelerating voltage and adjusting step number tends to linear relationship between the pulse generating circuit,waveform monitor and remote neutron scaler,multichannel analyzer test,each module is running smoothly;Compared to DC mode,single pulse spectrum can also be shown C,H,O wax containing three elements to model neutron,gamma ray and neutron activation isolated element capture spectroscopy,nuclear reaction information increased.Due to the limitation of experimental conditions,this paper only tests the operation status of DC and single pulse neutron generator,the actual test results: storage current,ion source voltage,accelerating voltage and adjusting step number tends to linear relationship between the pulse generating circuit,waveform monitor and remote neutron scaler,multichannel analyzer test,the normal operation of each module;Compared with the DC mode,single pulse mode neutron spectrum isolated capture spectrum element analysis to improve the accuracy.