Ris. NaI γ谱仪在不同类型沉积物中环境剂量率的应用研究

Application of Ris. NaI γ Spectrometer to Environmental Dose Rates in Different Types of Sediments

中文关键词:  Ris.NaIγ谱仪  环境剂量率  光释光测年  放射性核素分析

英文关键词:Ris. NaIγ spectrometer  Environmentaldose rate  Optically stimulatedluminescence dating  Radionuclideanalysis

中文摘要:

      光释光测年被广泛的应用于地球科学和考古学等领域的年代学研究，而如何准确测量环境剂量率是光释光测年的关键问题之一。研究利用丹麦 Ris. Nutech所提供的铀( U)、钍( Th)、钾( K)等标样，标定了实验室的 RGS-19A型 NaIγ谱仪。选择不同类型沉积物，进行了不同测量时间对实验结果的影响研究，结果显示随着测量时间增加，测量误差减小，在测量时间达到 6h就可满足其要求，可作为测试样品的固定测量时间；进一步对于岩性均一以及岩性不均一的 36个地质样品开展了 Ris. NaIγ谱仪法与 ICP-MS法， Ris. NaIγ谱仪法与中子活化法测定环境剂量率的对比研究。研究结果表明，对于大部分样品两组不同方法测量结果在误差范围内基本一致(±1σ)，NaIγ谱仪与 ICP-MS法及中子活化法的剂量率平均之比为 1.13±0.03(n=36)。说明研究仪器测量结果是可靠的，此仪器 Ris.NaIγ谱仪可以广泛应用于不同类型沉积物光释光测年的环境剂量率测量中。

英文摘要:

      Optically stimulated luminescence dating is widely used in geochronology research in the fields of earth science and archaeology. How to accurately obtain environmentaldose rate is one of the key prob-lems in optically stimulated luminescence dating. In this study，the Laboratory RGS-19ANaI γ spectrom-eter was calibrated using U，Th，K and other standard samples provided by Ris. Nutech in Denmark. Dif-ferent types of sediments were selected to study the influence of different measurement time on the experi-mental results. The results showed that the measurement error decreased with the increase of measurement time，and the measurement time could meet the requirements when it reached6 h，which could be used as the fixed measurement time of test samples. In addition，Ris. NaI γ spectrometer andICP-MS，Ris. NaI γ spectrometerandneutronactivationmethodwereusedforcomparativestudyofhomogeneousandheteroge-neous lithology samples. The results showed that for most of the samples，the measurement results of the two groups were basically consistent within the error range(± 1 σ).The average dose rate ratio of NaI γ spectrometertoICP-MSandneutronactivationmethodwas1.13±0.03(n=36).Thisindicatesthatthemea-surement results of this instrument are reliable，and the instrument can be widely used in environmental doseratemeasurementofdifferenttypesofsediments.