Design And Realization Of Portable Radiation Detector

During routine inspections and equipment maintenance of nuclear power plants,operators are usually required to carry portable equipment that can detect radiation doses to work on site.The built-in detectors used in the field of radiation detection in our country often cannot guarantee both a wide measurement range and measurement accuracy at low doses.In response to this problem,a radiation detector solution using dual GM counter tubes and plastic scintillators + photomultiplier tubes is proposed.The detector is designed to effectively solve the problem of insufficient range and accuracy.Large-scale environmental radiation monitoring equipment cannot be carried around during the maintenance of nuclear power plant equipment,and the upper limit range of the dose rate of small personal dose equipment is insufficient,and the overall accuracy is low.The portable radiation detection instrument designed for professionals to carry around can monitor the environment in real time.The radiation dose rate in the area within the range can also detect the surface contaminants of the inspected equipment.This paper analyzes the measurement principles of different types of radiation,and screens out detectors suitable for different types of radiation.According to the physical and electrical characteristics of the selected detectors,the corresponding signal conditioning circuits and discrimination circuits are designed to process the collected pulse signals,and the EMI protection design is strengthened in the corresponding supporting functional module circuits to minimize noise interference To achieve the purpose of counting pulses under the conditions.In terms of logic,through the improvement of the average counting algorithm model,a smooth average counting algorithm is designed to judge the sampled value and eliminate invalid values while reducing the average jump.The Modbus protocol is used to design RS485 communication transmission.The content of the protocol specifies the data format and provides CRC check to ensure the stability of data transmission.Using STM32F405RGT6 as the main controller,it controls the data transmission and reception between the host and the probe,the OLED screen display and the function of WIFI transmission and communication with the terminal server while the timer counts.By building an irradiation test system for verification,the radiation dose rate collected by the detector is obtained.By comparing with the true value,the accuracy and detectable dose rate range are improved to meet the on-site measurement requirements.The obtained measurement value is received by the host computer and matched and verified,which proves the robustness and reliability of the transmission process.