The Design Of Vehicle-channel Radiation Monitoring System

The Vehicle-channel Radiation Monitoring System is a type of γ-ray measurements used in mining, border, customs import and export, isotope analysis and even sudden isotope applications. It can detect the γ-ray from the vehicle that passing the channel quickly and correctly, and also it can distinguish between natural radioactivity and artificial radioactivity from the change and fluctuating natural background radiation. The Vehicle-channel Radiation Monitoring System is different from the traditional γ-ray measurement system which analyze the spectrum of γ-ray and analyze the artificial radionuclides quantitatively, it has less equipment and resources, and most of all the measurement time can greatly reduce to millisecond to second level, and also it can detect highly shielded artificial sources effectively.This article is based on the cooperation project " The Design of Vehicle-channel Radiation Monitoring System" of Zhi-yuan Equipment Co., Ltd. Fuzhou and Chengdu University of Technology.It mainly develops γ-ray car monitoring system to quickly measure to distinguish artificial radionuclides and natural radionuclides. The article focuses on the nuclear signal processing circuit, upper computer application development and fast recognition algorithm based on background compensation of the Vehicle-channel Radiation Monitoring System.The main contents of this paper can be divided into the following areas:1. To select the detector that based on the actual measurement needs.There are many measurement types and sensor types can be used under the current technological environment.The Vehicle-channel Radiation Monitoring System using large-area plastic scintillation probe as a sensor, a plastic scintillator detector belongs to an organic scintillator detector with respect to the spectrum from the structural material is more robust, and can be done sufficiently large area, has high sensitivity, more suitable for measurement channel environment. γ radiation and an organic scintillator mainly occurred in the Compton scattering detector poor resolving power of the spectrum details insensitive algorithm channel-type radiation measurement system that is based on the characteristics of the organic scintillator for fast measurements.2. To study γ-ray analysis that based on the background compensation. The main difficulty of the design of the Vehicle-channel Radiation Monitoring System has two. The first is how to identify quickly in the channel measurement environment, the second is how to distinguish between natural radioactivity and artificial radioactivity. In an actual measurement environment, the natural background radiation will be affected when the vehicle passes through the channel. The effect of large plastic scintillator and γ-radiation is mainly Compton scattering. So for the natural radiation background of γ-ray spectrum is almost constant pulse distribution. According to this feature, you can get a reference parameter to determine whether or not there is artificial sources. In actual measurement, if the measured parameter significantly higher than the natural background parameters, you can determine the presence of artificial γ source.Reference parameter is measured by setting the screening threshold calculated. The system design using two pulse amplitude energy threshold. The high threshold value is the maximum detectable γ artificial sources of energy, the low threshold values as low as possible, as long as the electronic noise can be stuck. The pulse count above the high screening threshold has nothing to do with whether there is artificial γ radiation. But the pulse count above the low screening threshold has something to do with whether there is artificial γ radiation. In an actual measurement environment, the ratio of the pulse integrator count on high and low thresholds is a constant if there has no artificial radiation.In an actual measurement environment, compare the ratio of the pulse integrator count on high and low thresholds with the constant that measured in environmental background. If the result is within the error range, it can be judged to be no artificial γ radiation, if the result is larger than the maximum error range, it can be judged to be artificial γ radiation. The maximum error range is determined the value of 20%-30%.3. To study the detector signal processing circuit. The effect of large area plastic scintillation crystal and γ-ray stimulate photons. After the transition and amplification you can obtain the nuclear signal.4. To design the acquisition control module. The acquisition control module mainly converts the signal to the count rate information. On the one hand, the acquisition control module collect and process the nuclear signal to get the count rate information. And on the other hand, the acquisition control module communicates with the control module.5. To design the control module. The control module as a signal transit module has two functions. On the one hand, the control module communicate with the acquisition control module, on the other hand with a upper computer application for interactive data, but also other devices such as a speed sensor receives the external signal and the control sound and light alarm The main function, gates, etc., control module is docked received useful signal analysis and unpack package delivery.6. To design the upper computer management application. The upper computer application that using Chinese interface has many functional modules. The entire software system consists of serial data communication module, data storage and viewing module, real-time data to update the display module, video surveillance and license plate recognition module, instrument control module, report generation module, control gates and audible alarm control, network operations function module and so on.In summary, this paper describes many parts of the Vehicle-channel Radiation Monitoring System, and also using the standard radiation sources to adjust the instrument. In the actual measurement, the instrument achieved the desired results and met the relevant national standards requirements.