Study On Single Pump Water Injection System In Multi-sphere Neutron Spectrometer

The multi-sphere neutron spectrometer is one of the devices commonly used for measuring the neutron energy spectrum.A new pumping water multi-spherical neutron spectrometer mainly uses water as the moderating layer,and changes the thickness of different moderating layers through the method of pumping water.Based on the difference in neutron slowing ability among different water layer thicknesses,the relationship between the counting rate response of neutron detectors and the neutron spectrum is studied,in order to analysis the incident neutron energy spectrum.This method can make the traditional multi-sphere neutron spectrometer removable or portable.This paper is funded by the National Natural Science Foundation Project "Multiple Concentric Pellets for a Wide Range of New Neutron Energy Spectrum Detectors(41774120)" and the Subtopic "Study on space radiation neutron spectrum analysis technology" of National Defense Research Foundation Project "Space Radiation Neutron Energy Spectrum Measurement and Dose Calibration Technique((JSJL2014404B001))".which aims at the pumping water system in the new pumping water multi-sphere neutron spectrometer and combines the needs of the spectrometer in the work efficiency,control accuracy,and production cost of the pumping water system.A single-pump pumping water system with pumping water power supplied by a centrifugal pump and a combined single-pass solenoid valve for pumping water mode control was developed.Through research,the following results have been obtained:1)According to the structural features of the new pumping water multi-sphere neutron spectrometer,the overall structure and working flow of the pumping water injection system are designed.Firstly,the water layer is controlled through the water flow path selection solenoid valve(K11~K15,K21~K25).Secondly,controlling the system water pumping operation through the pump and pumping water mode selection solenoid valve(K1,K2,K3,K4);Finally,the thickness of the moderator water layer is accurately calibrated with the sensors(D1,D2).2)The investigation and selection of functional modules such as solenoid valves,water pumps,and sensors were carried out,and the hardware design of the pumping water system was completed.Firstly,through the data analysis and experimental tests,the selection of the water flow path selection solenoid valve SEL-5,the pumping water mode selection solenoid valve HUARUISI24-2,the water pump DH324550,and the sensor SEN-HZ21 WA are completed.Secondly,the STM32 is used as the core processing unit to completed hardware design and debugging of the pumping water system,and the standby control mode manually controlled based on the DSIC05 LSGET,thus improving the stability and operability of the hardware system.3)The communication protocol was designed and the pumping water system driver was completed.According to the requirements of the pumping water multi-sphere neutron spectrometer,a modular design concept was adopted to design the communication protocol and control instructions of the pumping water system,and the driver program of pumping water system was completed,and the functions of command receiving and parsing,high-precision pumping operations,water thickness monitoring,and intelligent shutdown were realized.The main innovations of this paper:1)On the basis of the traditional centrifugal pumping water system,the multi-pass solenoid valves are used to independently control the thickness of the water layer,and the flow meter is used to achieve accurate control of the water layer thickness,which solves the problem of insufficient control precision of the traditional centrifugal pumping water system.2)The combination single-way solenoid valve is used to control the pumping water mode,which achieves single pump control of pumping water,thereby reducing the number of system pumps and reducing costs.