@article{oai:nagoya.repo.nii.ac.jp:00011728,
 author = {古澤, 秀樹 and Furuzawa, Hideki and 宮原, ひろ子 and Miyahara, Hiroko and 毛受, 弘彰 and Menjo, Hiroaki and 増田, 公明 and Masuda, Kimiaki and 村木, 綏 and Muraki, Yasushi and 中村, 俊夫 and Nakamura, Toshio and 北川, 浩之 and Kitagawa, Hiroyuki},
 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 content in each tree ring gives information on the change of solar activity in the past. Variation of the ^<14>C content shows that five grand minima, when the solar activity was extremely weak, existed in the last millennium. The Maunder Minimum(1645-1720 AD), one of the grand minima in the last millennium, is well known to have had almost no sunspots. To clarify the characteristics of solar activity during the grand minima, we have investigated the solar activity during the Sporer Minimum(1415-1534 AD) and Maunder Minimum. We mesured the ^<14>C content in the 714-year-old Yaku ceder tree from Sporer Minimum and the 392-year-old Murou-ji ceder tree from Maunder Minimum by the accelerator mass spectrometry(AMS). The time series of the ^<14>C data for the Sporer Minimum was analyzed by Fourie Analysis. The power spectrum shows peaks in the periodicity at 11.9yr and 28.6yr. The amplitude of 11.9yr period was stronger than that of 28.6yr. The 11-year cycle was extracted from the time series of the data by using band-pass filter. The 11-year cycle was suppressed during the 50 years of the mid Sporer Minimum. In Fourie Analysis of the ^<14>C data for the Maunder Minimum, the power spectrum shows no significant peak. We continue this study to get more detail characteristics of the solar activity during the grand minima., 第16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15年(2003年度)報告 Proceedings of the 16th Symposium on Researches Using the Tandetron AMS System at Nagoya University in 2003 日時:平成16(2004)年1月22日(木)､23日(金) 会場:名古屋大学シンポジオン Date:January 22nd and 23rd,2004 Place:Nagoya University Symposion Hall},
 pages = {113--119},
 title = {樹木年輪中^<14>C濃度測定による太陽活動極小期の研究(第16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15(2003)年度報告)},
 volume = {15},
 year = {2004}
}