Study of the solar activity in the past by measurement of radiocarbon in tree rings

通过测量树木年轮中的放射性碳来研究过去的太阳活动

• 批准号: 12440062
• 负责人: MASUDA Kimiaki
• 金额: $ 10.43万
• 依托单位: Nagoya University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12440062/
• 关键词: Solar activity; Cosmic ray; Radiocarbon; Spoerer minimum; Liquid scintillator; Accelerator mass spectrometer; Climate change; Maunder minimum; 放射線計測; 同位体効果

In order to investigate the variability of solar activity in the last millenium, the concentrations of radiocarbon in Yaku ceder tree rings have been measured. Until now, we have produced samples and measured the concentration of radiocarbon for the Spoerer minimum when the solar activity was lowered. The cellulose samples of AD1410 to 1480 were converted to benzene and radiocarbon activity was measured by the liquid scintillation (LSC) method. For the samples of AD1480 to 1530, radiocrbon activity was measured by the accelerator mass spectometry (AMS) because enough amount of benzene with high purity was not obtained. While a hundred gram of wood samples are necessary for good statistical accuracy for LSC method, only 10 mg is sufficient for AMS method. At present, obtainable accuracy is 0.3 to 0.4 % for LSC method and 0.4 to 0.5 % for AMS method. Although our final goal is the accuracy of 0.2 to 0.3 %, we have measured in rather worse accuracy as a first step.Until now, radiocarbon contents have been measured for almost all yearly samples of AD1410 to 1480 and for every wo year samples of AD1480 to 1530. Some samples were measured by the both method and the same activity was obtained within the error. Our results agrees well with the decadal radiocarbon contents in tree rings of North America by Stuiver.The variation of our radiocarbon contents is within ±0.5 % after removing the long term trend. This differ from the result for the tree rings of the Maunder minimum by Kocharov. Our periodicity analysis by MEM method shows a dominat peak of spectral density at 21 year. This is the same trend as that obtained for the Maunder minimum. The sun and interplanetary space might have different mechanism and structure of magnetism in the grand minima.

为了研究上一个千年的变异性，Yaku Ceder树环中的放射性碳的浓度使我陷入困境。 AD1410的纤维素样品被转化为苯，并通过液体闪烁液测量了放射性碳作用。目前，AMS的准确性为0.3至0.4％，对于AMS方法，我们的最终方法是AD1410的最终方法。到1480年，每年的AD1480至1530年的每年样本。 kocharov的最小值。

项目成果

植村恒仁: "シュペーラー極小期の^<14>C濃度測定"名古屋大学加速器質量分析計業績報告書. XIII(未定). (2002)

Tsunehito Uemura：“Späler 最小值期间 14 C 浓度的测量”名古屋大学加速器质谱仪性能报告 XIII（待定）。

Y. Muraki et al.: "Measurement of radiocarbon contents in leaves from some Japanese sites"Radio carbon. 43-2(in press). (2002)

Y. Muraki 等人：“日本一些地点叶子中放射性碳含量的测量”放射性碳。

増田公明: "宇宙線強度変動と^<14>C濃度変動"タンデトロン加速器質量分析計による^<14>C測定の研究成果報告書. XII(未定). (2001)

Kimiaki Masuda：“宇宙射线强度波动和^ 14 C浓度波动”使用tandetron加速器质谱仪XII进行^ 14 C测量的研究结果报告（待定）。

Y. Muraki: "Measurement of radiocarbon contents in leaves from some Japanese sites"Radiocarbon. 43(未定). (2002)

Y. Muraki：“日本一些地点叶子中放射性碳含量的测量”Radiocarbon 43（待定）。

Y.Muraki: "Measurement of radiocarbon contents in leaves from some Japanese sites"Radiocarbon. 43(未定). (2002)

Y. Muraki：“日本一些地点叶子中放射性碳含量的测量”Radiocarbon 43（待定）。