Optimization Of²²²Rn/²²⁰Rn Absolute Measurement Instrument Based On A Small Scintillation Cell

Up until now, co-measurement method and devices are really rare worldwide,and absolute measurement devices are still on the way. Though, devices for222Rnmeasurement are widely used, its measurement standards have not come into being.As a result, the research and development of device for²²²Rn/²²⁰Rn measurementcarry a lot of meanings for the co-measurement method, especially for theestablishment of220Rn measurement standards. Preliminary development ofinstrument for absolute measurement of²²²Rn/²²⁰Rn has been completed. Thesampling count,²²²Rn/²²⁰Rn concentration calculation and environmental parametersand the concentration of²²²Rn/²²⁰Rn PC display are basically realized. In otherwords, the instrument bears the basic functions needed for the²²²Rn/²²⁰Rn absolutemeasuring instrument.In order to the single small scintillation cell²²²Rn/²²⁰Rn absolute measurementprototype is more integrated, man-machine interface is more optimized, moreoperational and functional, which makes it more convenient for the future promotionof the instrument.This study is based on a preliminary prototype to optimize design,including hardware complementation, software refinement, prototype debugging andtechnical parameters test. The main contents are divided into three parts as follows.Design a low dead time pulse amplitude analyzer, carry out feasibility analysisby software simulation.A liquid crystal display module is used for real-time display of the environmentalparameters. Given that the complication of circuit and lack of I/O ports, design aenvironment parameter sampling and display I/O port conservation program, couplingwith SPI communication, to make the whole system occupies only7I/O ports. Thedesign of the man-machine interface optimization and save a large degree of port resources. The port resource is thus optimized.The sampling gas flow control. The control of gas flow is realized by pumpcontrol completed by the software via PWM method. Sampling flow precision controlafter experimental,get the duty ratio in good linear relationship between the samplingflow. This makes the prototype more operational.