北京市花岗石放射性水平调查及核素差异分析

目的 通过检测花岗石²²⁶Ra、²³²Th、⁴⁰K含量,探究可能影响放射性核素差异的因素,根据国家标准以及内外照射指数、镭当量、γ外照射有效剂量当量的计算结果和探究结论为今后在选择花岗石装修或制定防治措施方面提供指导性建议。方法 用ORTEC高纯锗(HPGe)γ谱仪测量北京市某石材交易市场采集的放射性样本镭、钍、钾核素含量和²²⁶Ra、²³²Th、⁴⁰K比活度。结果 不同产地、不同颜色的花岗石放射性核素的含量有差别:一般而言南方所产的花岗石放射性核素含量高于北方地区;颜色较深的花岗石核素含量比颜色浅的含量高。基性、超基性的岩石放射性水平比较低;未发生蚀变的岩石放射性水平较低;地质年代越久远放射性水平就越低。此结果仅是我们在选取的19中样品中总结出来的,仅作参考。结论 选购花岗石作为装饰材料时尽量选择放射性核素含量低的种类,结合国家安全标准注意其分类和适用范围,注意日常的防护措施,加强通风,加大建材产品监测监督力度,减少辐射对身体的伤害。

Investigation of Radioactivity Level and Analysis of Nuclide Differences on Beijing Granite

Objective To detect the content of ²²⁶Ra, ²³²Th, ⁴⁰K in granite, to explore the possible factors of radionuclide content, and make comclusions according to the national standards and the results of internal and external exposure index, radium equivalent, γ radiation effective dose equivalent to provide guidance for the choice of decoration with granite or formulat prevention measures in the future. Methods Using the ORTEC high purity germanium (HPGe) γ spectrometer to measure the contents and specific activities of ²²⁶Ra, ²³²Th, ⁴⁰K, the radioactive samples are collected in a stone trading market of Beijing. Results Radionuclide granite are diverse for the different regions and colors:Granites produced in south,such as Fujian, Guangdong and other places have higher radionuclide contents than that in the north region; Granite radionuclide contents with dark color are higher than the color of shallow. The radioactive level of basic rock and ultrabasic rock is low. The radioactive level of rock with no alteration is low. The longer the geological time,the lower the radioactive level. Conclusion To choose the type of low radionuclide content as the decorative materials, pay attention to the classification and the scope of application with the national safety standards, pay attention to the daily protection measures, to strengthen ventilation and to increase the monitoring and supervision of building materials are the measures to, for reduce the damage caused by radiation on the body.