Research And Design Of Neutron Generator Console Based On ARM

Neutron generator is a light equipment which can produce neutron rays,composed of neutron tube,high voltage power supply and control system.It can be shut off,easy to protection,small volume,light weight,long life,easy to carry,etc.Neutron generator has been widely applied in multiple fields such as oil well logging,industrial on-line analysis,explosive detection,etc.In this paper,according to some issues which appeared at the period of prior console designed by the project team running,a new console system of neutron generator is designed and developed based on LPC1768 embedded system.The console system includes memory,ion source,high pressure three driving power source,and human-computer interaction system.Firstly,we expound applicability and exploitability of ARM microcontroller which as the main controller in neutron generator console,design main control circuit with LPC1768 microcontroller circuit to coordinate relevant control work of console system.Secondly,we design driving circuits of multiple powers.Each driving power includes the output channel and the input channel: on output channel,program is designed in the main control chip,the PWM control signal is exported from main control circuit,which collocates PWM driving chip,isolating circuit and the second-order active low-pass filter circuit,to output the analog control signal via DA,and regulate the output of drive power;on input channel,AD collection circuit and isolating circuit can realize real-time acquisition about parameters of driving power and states of neutron tube,giving an error compensation method based on LPC1768 built-in 12 bit ADC,after compensation,the sampling accuracy of built-in ADC is 0.1%,for control scheme needed high precision,the parameter can be acquired by external 16-bit AD collection circuit owning higher accuracy,making AD accuracy increased to 0.03%.In addition,this paper abandons the traditional optical coupling isolation scheme to joins digital isolation circuit between each module,which to optimizes the isolation scheme in performance,power consumption,transmission rate and circuit volume,to improves the stability and anti-interference ability of control system.The isolated power supply module is used to realize independent power of every circuit module,to avoid interference between circuits,and to solve the ripple interference problem caused by switch power supply.Finally,on the human-computer interaction system,a multi-channels and self-protection's PC control software designed by LabVIEW platform replaces the touch screen scheme;The digital isolation serial port module of LPC1768 microcontroller realizes communication between the console with PC,increases stability and anti-interference ability of the serial communication,solves the crash issue of the serial port,guarantees the stable communication of the console and PC,realizes parameter acquisition and control function of various power supply of neutron generator.This paper improves the hardware circuit and structure,which deals with crash issue of main control board under emergency condition.At last,adding the stable algorithm,to realize automatic adjustment of console and stabilize the electrical parameters of neutron generator.In this paper,the system is tested in the new neutron laboratory.Test results: memory power,ion source power supply,high voltage source power's parameters and adjustment step of PC are close to linear adjustment,memory's regulation precision is 0.8 mA,ion source's regulation precision is 1.5 V,high pressure source's regulation precision is 0.07 KV;Under the rated working mode,the neutron generator's yields are stabled within ±2%;under "self-Stablization" mode,the neutron generator's electrical parameter are stabled within ±0.1%.In this paper,the console system of neutron generator designed by us is conform to using standard completely,the overall performance is better than previous generations console system designed by project team.The new neutron generator console system has been applied in National Major Scientific Instruments Development Project“Development and application of real time online testing instrument for industrial material composition(2013YQ040861)”,which satisfies project's integral requirements and works well.