氡析出率测量方法及优化研究

Radon is one of the major sources of natural radiation suffered by humanity. Meanwhile, the radon exhaled from building materials and soil is the main source of indoor radon, whose harm has aroused the people's attention. At present, the common measurements of radon exhalation rate methods are activated carbon adsorption-gamma spectrum, CR-39 nuclear track and Electrostatic collection have the problems: too long measurement time, Interfered by thoron, influenced by the temperature and relative humidity, and so on. The project intends to select the absolute humidity as the important parameters of the automatic temperature and relative humidity revision, to establish the theoretical model and the implementation of the program based on electrostatic collection method to auto correct the influence from temperature and relative humidity. The variation of the correction curve of absolute humidity with the changes of the size of the cavity, the sampling model and the electric field shape parameters can be obtained through theoretical analysis and experimental variation.The program is to study the method of Radon measurement, such as optimizing the sampling methods, sampling time and flow rate, the total measuring time, weighting factor and other measurement parameters during the measurement, to find a variety of measuring method for different media. Experiments and tests will be carried in the radon Key Laboratory, to build a fast and reliable device for measuring radon exhalation rate from medium.The success of this research will greatly improve the measurement and control level of radon exhalation rate of building materials, and the monitoring and evaluation level of environmental radon pollution, and provide the important technical support for the resource survey, geological research and earthquake prediction based on the tracer nuclides of radon.

氡是人类所受天然辐射的主要来源之一，室内氡主要源于建材和土壤的氡析出，其危害引起了人们的高度重视。目前活性炭吸附-γ测量、CR-39核径迹、静电收集等氡析出率测量常用方法,分别有测量时间长、钍射气干扰、受温、湿度影响等问题。本项目拟从静电收集法出发，选择绝对湿度作为温、湿度自动修正的重要参数，建立温、湿度自动补偿理论模型及实现方案；通过理论分析和实验，进一步得到腔体大小、探头型号、电场形状等参数变化时绝对湿度修正曲线的变化规律；同时优化氡析出率测量的取样方式、取样时间与流量、测量总时间、权重因子等在内的测量参数，获得适合多种介质的氡析出率快速、可靠测量方法。并利用氡重点实验室的条件开展实验及应用测试研究，搭建一种快速、可靠的介质氡析出率测量装置。研究成果将为提高我国建材氡析出率测量与控制水平、环境氡污染监测与评价水平以及氡为示踪核素的资源勘测、地学研究及地震预报水平等提供重要技术支持。

氡是人类所受天然辐射的主要来源之一，室内氡主要源于建材和土壤的氡析出，其危害引起了人们的高度重视。目前氡析出率测量常用活性炭吸附-γ测量、CR-39 核径迹等方法,但都有钍射气的干扰、测量时间长、受温湿度影响等问题，因此建立一种快速、可靠的氡析出率测量方法及优化研究具有重要的科学意义和应用价值。.项目组建立了静电收集法测氡自动温湿度补偿（修正）方法理论模型，在此模型基础上，建立了能够消除泄露、反扩散、环境氡本底的干扰的氡析出率测量方法，应用双室平衡法开展了氡析出率测量参数（取样方法、测量周期、集氡罩参数、抽气流率等）的优化计算和氡析出率的测量方法优化研究，并基于优化的氡析出率测量方法，利用LabVIEW平台设计完成了基于双室平衡法氡析出率优化测量方法的应用程序，为氡析出率测量提供测量参数的快速优化，利用新型NRL测氡仪、氡析出率参考标准装置等条件开展了氡析出率测量方法优化效果的实验验证及应用测试研究。研究成果将为提高我国建材氡析出率测量与控制水平、环境氡污染监测与评价水平以及氡为示踪核素的资源勘测、地学研究及地震预报水平等提供重要技术支持。