A study of heliosphere before 25000 years measuring a variation of 22-year for cosmic rays

25000年前日光层研究测量宇宙线22年变化

• 批准号: 17540230
• 负责人: SAKURAI Hirohisa
• 金额: $ 2.18万
• 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: 2005
• 资助国家: 日本
• 起止时间: 2005 至 2006
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-17540230/
• 关键词: cosmic rays; radiocarbon; single-yr tree rings; 25000 years ago; heliosphere; solar activity; 11-year; 22年変動; 年代測定; 地磁気変動

We have measured the ^<14>C concentrations in single-year tree rings of an old wood sample before approximately 25000years, using accelerated mass spectrometry (AMS). The ^<14>C concentrations of consecutive 26 single-year tree rings were measured producing the 60 graphite samples for the AMS. The counting accuracy was approximately 0.7% because of the measurement of two graphite samples for each tree ring. The radiocarbon age was 22271±118 yrBP on average for the 26 tree rings, indicating the calendar age of 26778±178 yrBP by the age calibration program of Faibanks0107. Time profile of the radiocarbon ages for 26 single-yr tree rings implied a variability with two humps indicating an interval of approximately 12-year. The heights of sharp and dull humps were 157 yrBP and 109 yrBP from the moving average curve, respectively. They are corresponding to the ^<14>C concentrations of 2.0% and 1.4%, respectively. As the ^<14>C concentrations of this era before 25000 years was 40% higher than that at present time, the variation is suggestive solar periodic activities such as 11-year and/or 22-year.

我们用加速质谱仪(AMS)测量了大约25000年前的一个老木材样品的一年生树木年轮中的~(14)C浓度。测量了连续26个一年生年轮的14&C浓度，产生了60个用于AMS的石墨样品。由于每个树轮测量了两个石墨样品，因此计数精度约为0.7%。26个年轮的平均放射性碳年龄为22271±118yrBP，根据Faibans0107的年龄校正程序得到的日历年龄为26778±178yrBP。26个一年生年轮的放射性碳年龄的时间分布暗示了一个变异性，两个驼峰表明间隔约为12年。尖峰和钝峰的高度分别比移动平均曲线高157yrBP和109yrBP。它们分别对应于2.0%和1.4%的^&lt；14；C浓度。由于25000年前这个时代的~(14)&C浓度比现在高40%，这种变化暗示了太阳周期活动，如11年和/或22年。

项目成果

<14>^C DATIG OF ~2500-YR-OLD CHOUKAI JINDAI CEDAR TREE RINGS FROM JAPAN USIG HIGHLY ACCURATE LSC MEASUREMENT

<14>来自日本 USIG 的约 2500 年历史的町海金代雪松年轮的 ^C 数据高精度 LSC 测量

• 发表时间: 2006
• 期刊: Radiocarbon Vol. 48
• 作者: W.Kato;H.Sakurai et al.;櫻井敬久;H.Sakurai et al.
• 通讯作者: H.Sakurai et al.

極低レベル^<14>C,^7Be放射能測定による過去の宇宙線強度変動の検出

通过测量极低水平的^<14>C,^7Be放射性来检测过去的宇宙射线强度波动

• 发表时间: 2006
• 期刊: RADIOISOTOPES 55・No.8
• 作者: T.Kondo;T.Kondo;M.Abe;I.Okamura;近藤 敏啓(共著);櫻井 敬久
• 通讯作者: 櫻井 敬久

Light Yields and Pulse-Height Spectra of High-Purity Teflon Vials for Accurate <14>^C Measurement in Old Tree Rings

高纯度聚四氟乙烯小瓶的光产率和脉冲高度光谱，用于准确测量老树年轮中的 <14>^C

• 发表时间: 2006
• 期刊: LSC 2005, ADVANSES IN LIQUID SCINTILLATION SPECTROMETRY
• 作者: W.Kato;H.Sakurai et al.
• 通讯作者: H.Sakurai et al.

Measurement of time variations of cosmic rays in the past by ultralow level 14C and 7Be radioactivity

利用超低水平14C和7Be放射性测量过去宇宙线的时间变化

• 发表时间: 2006
• 期刊: RADIOISOTOPES 55
• 作者: W.Kato;H.Sakurai et al.;H.Sakurai
• 通讯作者: H.Sakurai

Light Yields and Pulse-Height Spectra of High-Purity Teflon Vials for Accurate ^<14>C Measurement in Old Tree Rings

高纯度聚四氟乙烯小瓶的光产率和脉冲高度光谱，用于准确测量老树年轮中的 ^<14>C

• 发表时间: 2006
• 期刊: LSC 2005, ADVANSES IN LIQUID SCINTILLATION SPECTROMETRY
• 作者: W.Kato;H.Sakurai et al.
• 通讯作者: H.Sakurai et al.