| The rapid measurement of 222 Rn/ 220 Rn concentration can provide valuable information for radiation protection and environmental protection. In addition, 222 Rn / 220 Rn absolute measurement instrument based on a small scintillation cell can be used to calibrate the radon measurement instrument of relative measurement method. There is no such instrument at home and abroad. Therefore, the development of 222 Rn / 220 Rn absolute measurement instrument based on a small scintillation cell is of great significance.This paper is the basis of the preliminary prototype of 222 Rn / 220 Rn absolute measurement instrument based on a small scintillation cell studied by Zhou Jian-bo, Liu Liyan, Zhang Jiayue at the university of south China. The design of the hardware circuit has been added, the problem of high and low voltage power supply has been solved. The main contents are divided into five parts as follows.Firstly, optimize a low dead time pulse amplitude analyzer, and carry out experimental verification. Experimental results showed that the optimized circuit is not only feasible, but also can work properly and reliably when the sine wave input signal frequency increase up to 2.2MHz.Secondly, design a linear pulse amplifier based on S- K. The linear pulse amplifier has advantages such as simple circuit structure, few components. It shows good performance and effect in operation.Thirdly, choose to buy a high voltage module for photomultiplier tube and a regulated power supply with quad output. the problem of high and low voltage power supply has been solved.Fourthly, through the switch buttons, the gas velocity of the micro pump is controlled by the PWM duty cycle.Fifthly, the temperature,pressure, humidity, gas velocity, pum duty cycle, the count of the first stage, the count of the second stage is realized on liquid crystal module. 222 Rn / 220 Rn absolute measurement instrument based on a small scintillation cell has been basically completed. |
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