A Study of Cosmic Ray Spectrum due to Measurements of yearly time variations for Cosmic Ray Intensity in the Past 2500 year

近2500年宇宙线强度年时变化测量的宇宙线谱研究

• 批准号: 10640245
• 负责人: SAKURAI Hirohisa
• 金额: $ 2.43万
• 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: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10640245/
• 关键词: Cosmic Rays; C-14(Radiocarbon); Solar periodicity of 11 year; Ancient time; 放射性炭素; 太陽活動; 年代測定

There are no data related to the 11-year cycle for more distant times (I.e. > 1000 years ago). To address this, we have started to measure, at single year intervals, the concentrations of 14C in old tree rings of wood buried ca. 2500 years ago by a volcanic eruption. (1) Constructed highly accurate 14C measuring system is composed of a benzene synthesizer capable of producing a large quantity (10 g) of benzene and a Quantulus 1220TM liquid scintillation counting system. (2) The accuracy is < 0.2% for measurements of the 14C concentration for single-year tree rings. (3) To estimate the calendar age of the wood, we carried out 14C dating for three tree rings form the wood, sequentially separated by 100 years and 130 years. The results were 2475 B.P., 2503 B.P., and 2410 B.P. for the rings, respectively. From these results, the wood most probably dates from 485 B.C., using Stuiver's calibration data. (4) We have sequentially measured the concentrations of the 8 single year tree rings. The standard deviation was 0.3% for the average and the maximum variation was 0.5%. Using our 14C measuring system for the single year tree rings, we can investigate the cosmic ray spectrum in the ancient time for variations of 0.3% 14C concentrations corresponding to 30% variations of cosmic ray intensities.

没有关于更远时间（即> 1000年前）的11年周期的数据。为了解决这个问题，我们已经开始测量，在一年的时间间隔，14C的浓度在老树木年轮的木材埋约。2500年前的火山爆发。(1)构建的高精度14C测量系统由能够产生大量（10g）苯的苯合成器和Quantulus 1220TM液体闪烁计数系统组成。(2)对一年年轮的14C浓度测量的准确度< 0.2%。(3)为了估计木材的日历年龄，我们对木材中的三个树木年轮进行了14C测年，依次间隔100年和130年。结果是2475 B.P. 2503 B.P.，和2410 B.P.。从这些结果来看，木材最有可能是公元前485年，使用Stuiver的校准数据。(4)我们连续测量了8个单年树木年轮的浓度。平均值的标准偏差为0.3%，最大变异为0.5%。利用我们的单年树木年轮14 C测量系统，我们可以研究古代宇宙射线谱，0.3%的14 C浓度变化对应于30%的宇宙射线强度变化。

项目成果

A.Suzuki: "Pulse Height Distributions of Brays in C-14 measurement with Liquid Scintillation Counting System Quantulus"IEEE Trans.Ns. 46.NO3. 302-305 (1999)

A.Suzuki：“使用液体闪烁计数系统 Quantulus 进行 C-14 测量中的布雷脉冲高度分布”IEEE Trans.Ns。

H.Sakurai: "High Accurate C-14 Measurement of an Old Tree Rings in the Past 2500 years"26th Int.Cosmic Ray Conf.. 7. 425-428 (1999)

H.Sakurai：“过去 2500 年老树年轮的高精度 C-14 测量”第 26 届国际宇宙射线会议 7. 425-428 (1999)

H.Sakurai: "High Accurate C-14 Measurement of an Old Tree Rings in the Past 2500 years"Proc.26th.Int.CosmicRay Conf.. 7. 425-428 (1999)

H.Sakurai：“过去 2500 年老树年轮的高精度 C-14 测量”Proc.26th.Int.CosmicRay Conf.. 7. 425-428 (1999)

A. Suzuki, H. Sakurai et. Al.: "Pulse Height Distributions of Brays in C-14 measurement with Liquid Scintillation Counting System Quantulus"IEEE Trans.. NS46. 302-305 (1999)

A.铃木，H.樱井等。

H. Sakurai et al.: "High Accurate C-14 Measurement of an Old Tree Rings in the Past 2500 years"Proc. 26th Int. Cosmic Ray Conf.. 7. 425-428 (1999)

H. Sakurai 等人：“过去 2500 年古树年轮的高精度 C-14 测量”Proc。