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.

使用加速的质谱法（AMS），我们已经在大约25，000年之前测量了旧木样品的单年树环的 ^<14> C浓度。测量连续26个单年树环的 ^<14> C浓度，为AMS产生60个石墨样品。计数精度约为0.7％，因为每个树环对两个石墨样品进行了测量。 26棵树环平均为22271±118 YRBP，这表明FAIBANKS0107的年龄校准计划表明日历年龄为26778±178 YRBP。 26个单年树环的放射性碳年龄的时间曲线暗示了一个可变性，两个驼峰表明间隔约12年。尖锐和暗淡的驼峰的高度分别为157 YRBP和109 YRBP，分别是移动平均曲线的高度。它们分别对应于2.0％和1.4％的 ^<14> C浓度。由于在25，000年之前的这个时代的 ^<14> c浓度比目前高40％，因此这种变化是暗示性的太阳能周期性活动，例如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.

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.

LIGHT YIELDS AND PULSE-HEIGHT SPECTRA OF HIGH-PURITY TEFRON VIALS FOE CCURATE 14C 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不利于老树年轮中精确的 14C 测量

• 发表时间: 2006
• 期刊: RADIOCARBON (accepted to be published)
• 作者: H.Sakurai;et al.;櫻井 敬久;H.Sakurai et al.
• 通讯作者: H.Sakurai et al.