【作者】 姜海静；

【导师】 葛良全；

【作者基本信息】 成都理工大学 ， 核技术及应用， 2005， 硕士

【摘要】 本文介绍了一套基于控制器局域网(CAN)总线的土壤测氡系统。该系统采用无源被动扩散法收集土壤气氡,测量机埋入土壤对壤中气氡做长期连续监测。采用金硅面垒半导体探测器进行α射线探测,并同时进行温、湿度及气压等多参数监测。引入CAN总线技术,可组成局域测氡网络,进行多点同时测量。在野外现场,测量机可脱离PC机,由便携操控器配置好工作参数后独立工作,按预设工作时间定时测量并自动保存α计数值、温、湿度、气压与测量时间等测量结果。该结果可由便携操控器灵活查看,或通过CAN总线经由CAN-HUB调入微机。 经实测,系统样机本底计数不大于2脉冲/小时。温、湿度和压强测量的最小分辨率分别为:0.1℃、1%和10Pa。测量单机平均功耗约为0.8W,可由12V电池或交流适配器供电。 应用本系统,在室内空气中进行多天实测,对α计数值与气象因素的关系进行初步研究。试验表明,温度与氡气测量值之间呈现较好的正相关性;而气压与α计数值呈明显的负相关;相对湿度与氡测量值间的相关性不是很明显,但相对湿度最低值处对应α计数值最高。 本系统能满足地震火山预报,灾害地质监测,以及环境放射性水平调查等多领域的测氡需求,具有较高的性价比和广阔的市场前景。更多还原

【Abstract】 A radon in soil gas measuring system based on Controller Area Network (CAN) bus is developed and introduced in this paper. Probes of the system can be buried in soil for radon long term measuring continuously. Undisturbed passive diffusing methods was used to collect radon in soil gas. A semi-conductor detector, Au surface-barrier type, was adopted for alpha particle detecting. Mean while, some parameter, such as gas temperature, pressure, and relative humidity, etc, was measured as well. An area radon detecting network can be set up for multi-point measurement at the same time, due to the technique of CAN bus. When configured with a portable control machine, probes can be running in a self-operate mode. Thus, no microcomputer is required. The self-operate mode means starting detecting according to the configured schedule, and the result, such as counting rate of alpha particle, gas temperature, pressure, and relative humidity, etc, will be saved automatically. These data can be conveniently display on the screen of the portable control machine, or copied to a microcomputer via the CAN bus.The protocol system was test. The counting rate of background is less than 2 counts per hour. The detecting resolution for gas temperature, pressure, and relative humidity is corresponding 0.1℃, 10Pa, and1%. The system can be powered from either a 12Volts battery or an AC adaptor. And the average power consumption for each probe is about 0.8Watts.Measuring work was done for days in air at room, in order to elementary study on the relationship between the counting rate of alpha particle and the meteorological condition. Results show that there was a significant positive correlation between the counting rate of alpha particle and air temperature. A significant passive dependence of the radon concentration on the atmospheric pressure was also found. And no appreciable dependence on relative humidity was revealed. But the minimum value of the humidity appeared when the radon concentration reached the maximum value.The system can meet the requirement on region of volcano and earthquake event forecast, catastrophic geological event monitor, and environmental radiation level survey, etc. It has better cost efficiency and would have a broadly market.更多还原