@article{oai:nagoya.repo.nii.ac.jp:00011700,
 author = {宮原, ひろ子 and Miyahara, Hiroko and 古澤, 秀樹 and Furuzawa, Hideki and 増田, 公明 and Masuda, Kimiaki and 村木, 綏 and Muraki, Yasushi and 中村, 俊夫 and Nakamura, Toshio},
 journal = {名古屋大学加速器質量分析計業績報告書},
 month = {Mar},
 note = {Radiocarbon ^<14>C, which is one of cosmogenic radioisotopes, is a good index of change in the solar activity. Investigation of the ^<14>C contents in each tree ring gives information on the change of solar activity in the past. We have focused on the solar variation during the grand minima, when the solar activity was extremely weak and almost no sunspot appeared. In some prior studies, the existence of the 22-year periodicity during the Maunder Minimum (1645-1720 AD) was suggested. To clarify whether the 22-year periodicity is common in the grand minima, we have investigated the solar activity during the Spoerer Minimum (1514-1534 AD). We measured the ^<14>C contents in the 714-year-old Japanese cedar tree by the accelerator mass spectrometry (AMS). Time series of the data were examined by Fourier analysis and by the band pass filtering. They showed the following periods; 7.4yr, 10.8yr and 23.3yr. The amplitude of 10.8yr period was stronger than that of 23.3yr, though the feature of amplitude variation of them differed. The periodicity of 22 years showed constant amplitude, however 11-year cycle was attenuated during the mid 40 years of the Spoerer Minimum. During the mid 40 years, the amplitude of 11-year cycle and 22-year cycle were equivalent. Thus, It is possible to say that the 22-year periodicity can be observed when the solar activity is quite weakened. We continue this study to get more detailed characteristics of the solar activity during the grand minima., 第15回名古屋大学タンデトロン加速器質量分析計シンポジウム(平成14年(2002年度)報告 Proceedings of the 15th Symposium on Researches Using the Tandetron AMS System at Nagoya University in 2002 日時:平成15 (2003)年1月30日(木)､31日(金) 会場:名古屋大学シンポジオン Date:January 30th and 31st,2003 Place:Nagoya University Symposion Hall},
 pages = {66--71},
 title = {年輪中^<14>C濃度測定によるシュぺーラー極小期の太陽活動の研究(第15回名古屋大学タンデトロン加速器質量分析計シンポジウム(平成14(2002)年度)報告)},
 volume = {14},
 year = {2003}
}