Intensities and Spectrum of Cosmic Rays in the past of 25000 years

过去25000年宇宙线的强度和光谱

• 批准号: 14540240
• 负责人: SAKURAI Hirohisa
• 金额: $ 2.3万
• 依托单位: Yamagata University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-14540240/
• 关键词: Cosmic Rays; Radiocarbon; Dating; AMS; Multi-cathode; LSC; 25000 years ago; step change; 宇宙線; 極低レベル液体シンチレーション測定; AMS測定; 3.4%ステップ的変化

We have measured the ^<14>C concentrations in single-year tree rings of old wood, using a multicathode by accelerated mass spectrometry (AMS). The ^<14>C concentrations of ten single-year tree rings were measured at intervals of 10, in 100 tree rings. For each single-year tree ring sample, typically 80 measurements of the ^<14>C concentrations were carried out using multicathodes. The sample standard deviations indicated that there are other fluctuations of typically 1.5% in addition to the fluctuation of the Poisson counting statistics that is typically 3% for each measurement. The average radiocarbon date of the tree rings was 22,130±306 BP for all 624 data measured by the multicathodes for the single-year tree ring samples. From the calibration data of Lake Suigetsu, the calendar dates of these one hundred tree rings were located between cal 25,400 yr BP and cal 26,150 yr BP. The radiocarbon dates changes between 21,979 Bp and 22,272 BP with error of approximately 50 BP, corresponding to the precision of approximately 0.5%. There was a step with a change of approximately 144 BP for each ten years in the time profile.

我们用多道加速质谱仪(AMS)测量了一年生老木材年轮中的~(14)C浓度。在100个年轮中，每隔10年测定10个一年生树轮的~(14)C浓度。对于每个一年的年轮样本，通常使用多个轨道对14&gt；C浓度进行80次测量。样本标准偏差表明，除了泊松计数统计数据的波动外，还有其他通常为1.5%的波动，每项测量的波动通常为3%。一年生树轮样品的624个年轮样品的平均年轮放射性碳测年为22,130±306个碱基。根据绥格苏湖的校准数据，这100个树木年轮的日历日期位于卡尔25400年和卡尔26150年BP之间。放射性碳测年在21,979~22,272 BP之间变化，误差约为50BP，对应的精度约为0.5%。在时间分布中，每十年有一个大约144个BP的变化。

项目成果

T.Gandou, H.Sakurai, et al.: "C-14 Concentrations of Single-Year Tree Rings From About 22,000 Years Ago Obtained Using a Highly Accurate Measuring Method"Radiocarbon. 46. (2004)

T.Gandou、H.Sakurai 等人：“使用高精度测量方法获得约 22,000 年前单年树木年轮的 C-14 浓度”放射性碳。

T.Gandou, H.Sakurai, et al.: "C-14 Concentration of Single Year Tree Rings From About 22,000 Years Ago Obtained Using a Highly Accurate Measuring Method"Radiocarbon. 46. (2004)

T.Gandou、H.Sakurai 等人：“使用高精度测量方法获得约 22,000 年前单年树年轮的 C-14 浓度”放射性碳。

H.Sakurai, et al.: "Characteristics of high-purity teflon vial of 14C measurement in old tree rings"Nucl.Instr. and Meth.In Physics Research A. 505. 454-457 (2004)

H.Sakurai等人：“老树年轮中14C测量的高纯度聚四氟乙烯小瓶的特性”Nucl.Instr.

H.Sakurai: "Characteristics of high-purity teflon vial of 14C measurement in old tree rings"Nucl. Instr. and Meth. in Physics Research A. 500号. 454-457 (2003)

H. Sakurai：“老树年轮中 14C 测量的高纯度聚四氟乙烯小瓶的特性”《Nucl. and Meth》，物理研究 A. No. 500. 454-457 (2003)

H.Sakurai, et al.: "AMS measurement of C-14 concentration in a single-year ring of a 2500-year-old tree"Mucl.Instr.and Meth.B. 2004.

H.Sakurai 等人：“AMS 测量 2500 年树龄树木单年轮中的 C-14 浓度”Mucl.Instr.and Meth.B。