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The Institute for Space–Earth Environment Research (ISEE), Nagoya University, carries out a wide range of interdisciplinary joint research to understand the earth system including human beings and the solar-earth system. The Division for Chronological Research, ISEE, is promoting wide range of interdisciplinary joint use and research on chronological, paleoenvironmental, geochemical, geological, and archeological studies through the ISEE joint research programs of 09) AMS joint research, and 10) 14C analysis service, in addition to the categories of 01), 02) international joint research, 04) general joint research, and 06) symposium. Many papers on the studies carried out by the ISEE joint use and research program were published in FY2021. Here is an overview of the joint research performed at Division for Chronological Research, ISEE.

The Institute for Space–Earth Environment Research (ISEE), Nagoya University, carries out a wide range of interdisciplinary joint researches to understand the earth system including human beings and the solar-earth system. The Division for Chronological Research, ISEE, is promoting chronological and paleoenvironmental joint researches using the AMS (Accelerator Mass Spectrometry) and CHIME (Chemical U-Th Total Pb Isochron Method) by ISEE joint research programs of 09) use of AMS, etc. (joint research), and 10) use of AMS, etc. (14C measurement service) in addition to general categories of 01), 02) international joint research, 04) general joint research, and 06) research meetings. I report a brief of outline of our joint researches in FY2018, FY2019, and FY2020.

It is important to know current situation of hydrological condition including its tendency for effective water-related disaster risk management. This study investigates trend and extreme characteristics of recent precipitation in Japan with AMS(Annual Maximum Series) and POT(Peaks Over Threshold(100mm)) at 155 meteorological observatories. It shows that most rainfall stations show slight decrease trend in annual precipitation but slight increase in annual maximum daily precipitation. Average of all rainfall stations in Japan is in significantly increasing trend. Events exceeding 100mm/day is significantly increasing in 1901-2014 while 1940-2014 is in just slight increase. Even in 1940-2014, the largest 50th rainfall in Japan shows significant and steady increase. These results show the importance of POT analysis not only AMS data. The advantage of this method would be with not only observation data but GCM data.

抗菌薬の不適正な使用による耐性菌の増加が問題となってきている。そのため、抗菌薬の適正使用を推進する目的で抗MRSA薬及び広域抗菌薬の使用に際しては届出制度を実施していたが、管理が不十分であった。そこで、感染防止対策加算の要件に伴う形で院内感染対策委員会の指導のもと、2012年11月に抗菌薬評価チーム（抗菌薬 Under Monitoring And Guidance Support : KUMAGUS）を立ち上げた。当チームは監視対象抗菌薬（注射用抗MRSA薬、注射用キノロン薬、カルバペネム系抗菌薬）の使用状況のモニタリング及び処方医へのフィードバックを行い、抗菌薬の適正使用を推進している。支援症例の多くが「薬物血中濃度の実施状況」、「培養結果に基づいたde-escalationがされていない」、「漫然と長期投与されている」といったケースである。この不適切な抗菌薬投与を減らし、より安全で効果的な感染症治療を行うために活動を行っている。

It is well known that ages of ancient iron artifacts can be measured by using carbon contained in the iron artifacts. As a simple method of carbon extraction from iron artifacts, a normal quartz tube is used for metal iron combustion at the temperature of 1000℃ for about 15 hrs. We tested the quartz tube method of metal iron combustion successfully for metal iron in fine fragment forms and reported the results previously. In Japan, iron rust samples are commonly excavated from archeological sites of the Kofun period and after. We have tested to collect carbon from iron rust samples successfully by the quartz tube method of iron-rust combustion at 850℃ for 3 hr. We have experienced that quartz tubes were broken twice during combustion: at 900℃ for 8 hr and at 850℃ for 3 hr. 14C age, 524±25 BP, was obtained for an iron rust sample from a ruin of Fe manufacturing site worked at 1850s in Saga city, Saga Prefecture, Japan. The 14C age was too old compared with the estimated age of the site. 14C ages were also obtained for three rusty nail samples as 2949 -3244 BP. The results suggested a possibility of modern carbon contamination in considerable amount during rust process of metal iron that was produced by using coal as a heating fuel as well as material to reduce iron oxide ore., 名古屋大学年代測定総合研究センターシンポジウム報告

In 2013, Typhoon 18 hit Kinki area and caused serious damages. During the torrential rainfall an emergency warning for heavy rain was issued to Kyoto, Shiga and Fukui prefectures; it is the first in all Japan since the emergency warning was established on 30th August in 2013. This emergency warning is issued when rainfall of return period of several decades occurs. The basin average rainfall broke historical record for return period 200 years in 24 hours at the reference point Hirakata of the Yodo river. The flood water overtopped the embankment and caused inundation along the Katsura river. This manuscript describes frequency analyses of basin averaged rainfall and discharge at Hiyoshi dam and six principal points in the Yodo river basin.

It is well known that ages of ancient iron artifacts can be measured by using carbon contained in the iron artifacts. As a simple method of carbon extraction from iron artifacts, a normal quartz tube is used for metal iron combustion at the temperature of 1000℃ for about 15 hrs. We tested the quartz tube method of metal iron combustion successfully for metal iron in fine fragment forms and reported the results previously. In Japan, iron rust samples are commonly excavated from archeological sites of the Kofun period and after. We have tested to collect carbon from iron rust samples successfully by the quartz tube method of iron-rust combustion at 850℃ for 3 hrs. We have experienced that one sample was broken during combustion at 850℃ for 3 hrs. A 14C measurement of only one sample has already been done, but it showed a possibility of a modern carbon contamination in considerable amount during rust process of metal iron., 名古屋大学年代測定総合研究センターシンポジウム報告

It is well known that age of ancient iron artifacts can be measured by using carbon contained in the iron artifacts. A RF furnace has been normally used to melt and oxidize the iron artifacts and to extract carbon from them as a form of CO2. This method, however, requires an expensive equipment and takes time for carbon extraction. As an another method, normal quartz tube is used for metal iron combustion at the temperature of 1000℃ for about 15 hours. We tested the quartz tube method of metal iron combustion successfully for metal iron in fine fragment forms. Almost 100% recovery was attained when metal iron weight is less than 15% of CuO that is used as an oxidizer. As a second stage of our experiment, we are planning to combust a big lump of metal iron., 名古屋大学年代測定総合研究センターシンポジウム報告

In order to study about the formation and development of the rice paddy cultivation technology in East Asia, it is important to arrange correctly the result (data) taken in various fields, such as agriculture, botany, and archaeology, in the time and space. This report is discussing rice paddy cultivation of East Asia, introducing the result of the field survey in China or Japan. And, I also introduce about a part of result of the study (Study on age determination by carbon in plant opal collected from ancient agricultural field) which we are tackling now., 名古屋大学年代測定総合研究センターシンポジウム報告

From various restoration experiments of iron-manufacture, it was revealed that charcoal used as a fuel remained in the newly produced iron during the iron production and iron reprocessing stage. However, a possibility that carbon other than that for fuel is mixing into iron products is fully expected. Moreover, a possibility that change will appear in the stable carbon isotope ratio in the manufacture process of ironware is suggested. So, measurements of 14C ages and carbon stable isotope ratios were performed for the samples which were obtained through iron manufacture and blacksmith experiments, and thus we inspected the validity that a precondition and the change of the stable carbon isotope ratio can be used as the basis of age determination of iron products. As a result in the smelting experiments with and without flux, CaCO3, containing no 14C, any tendency that carbon other than the charcoal used for fuel has affected 14C ages as well as stable carbon isotope ratios was not detected, and the validity of the precondition was accepted. However, some changes in 14C concentrations and the stable carbon isotope ratios were detected by the differences in materials used for iron forging processes., 名古屋大学年代測定総合研究センターシンポジウム報告

A new graphitization system for small-mass sample (, 0.5mg以下の炭素を含む試料の測定を目的とした新たなグラファイト化ラインが構築された。この新しいグラファイト化システムでは､グラファイト化反応器を従来よりも低容積にし､副生成物の水を-90℃で冷却除去､さらにH2/CO2比を大きくすることにより反応(CO2＋2H2→2H20＋C)を促進させ､グラファイト化効率や反応速度の増大､汚染炭素の低減を図っている｡触媒として用いたFe量は約1.5mgとし､またターゲットも従来の2.0mm径の穴のものから1.5mm径の穴のものに変えることで､グラファイトの厚みを十分にし､Csビームによるスパッタリングでグラファイトが無くなってしまわないようにした｡また､新しいグラファイト化ラインの構築に伴って､専用の炉を作成した｡本研究ではこの新しいグラファイト化ラインの検討のために､HOx-Ⅱ､2種類の14C世界標準試料(IAEA-C5､LAEA-C8)および14C-free HOx(0.07-0.55 mgC)の測定を行った｡12C3＋ビーム強度は炭素量が減少するにつれて弱くなり､14C/12C比も減少する傾向がみられた。しかし､13C/12C比による同位体分別の補正を行うことで、正しい14C濃度を得ることが可能であった｡従来と比較した新しいグラファイト化ラインと作成した炉についての詳細と､標準試料を用いたグラファイト化ラインの信頼性の検討について詳しく説明する｡, 名古屋大学年代測定総合研究センターシンポジウム報告

A plan to establish an AMS facility dedicated to radiocarbon (14C) measurement, discussed by Prof. Nakai and his colleagues, was authorized in 1978 at Nagoya University. Dr. Ken Purser, the president of General Ionex Corporation, USA, was invited to Nagoya University to present a talk on his plan to manufacture an ultra-sensitive mass spectrometer for natural-level 14C measurement. In the end, his second product, a model 4130-AMS 14C analyzer, was successfully introduced into the Radioisotope Center, Nagoya University, in 1981/82. The first 14C signal was detected with the machine in February 1983 and routine 14C measurements were started in the autumn of 1983. The AMS system has processed totally 8,612 unknown samples by July in 2000, after that time, he transferred his role of 14C measurements to another new successor. A second AMS system, dedicated to high-precision and high-accuracy 14C measurement, with a recombinator system to measure three carbon isotopes 12C, 13C and 14C simultaneously, produced by High Voltage Engineering Europe BV, The Netherlands was installed in 1996/97. The machine has been in operation since 2O00. The initial stage of 14C-AMS research at Nagoya University is summarized in this article., 第23回名古屋大学年代測定総合研究センターシンポジウム平成22(2010)年度報告

The AMS facility at Center for Chronological Research, Nagoya University, is performing ^C analysis of various organic samples for many research projects in archaeology, earth sciences, environmental studies and so on. Recently, we are increasingly demanded for ^C analysis of small-mass samples in these projects, and we have just started to establish a small-mass sample preparation system. In this first step, NIST Ox-II standard samples below 0.6 mgC, graphitized using our regular sample preparation protocol, were measured for ^C. The small-mass samples produced low graphite yield and decreased ^C^3+ beam currents. ^C/^C ratios were affected by the decrease in beam current intensity generated by samples 5 where amount of Fe catalyst is fixed to ～3mg in sample graphitization. Ion beam currents from targets produced with less catalyst were initially higher compared with those from targets with the usual amount of ～3mg Fe catalyst, but they did not last long and collapsed immediately as the sample was being sputtered by the Cs beam. Therefore, the graphite reduced on ～ 3mg of Fe, regardless or sample size, could give better ^C/^C result. For samples with, 1-1.5mgCの試料を調製するために使用している当センターの通常のシステムを用いて、0.2-0.6mgCの微量のシュウ酸標準試料を調製した場合に、どの程度の^C測定精度･確度が得られるかどうかの検討を行った。微量試料の場合、通常の試料量の場合に比べてグラファイト率が低下し、^C^3+ビーム強度がかなり低い結果となった。特に0.3mgC以下の試料においては、ほとんどビーム強度が得られず、^C/^C比は明らかに低い値を示した。Fe/C比を2-3に調製したターゲットは、Fe/C比が5以上のターゲットより、はじめはイオンビームが高いが、測定過程で急激に減少し、結果的に確度も精度も悪い結果となった。これらのことから、今後、試料量にかかわらず、Fe量は3mgにし、穴径の小さいターゲットを使用する必要があると考えられる。さらに、グラファイト化の際に生成する水を効率的にトラップし、高グラファイト率な"微量飲料に特化したグラファイト化システム"を構築する必要がある。

Quartz samples, which were collected at up to 70 cm (120 g/㎠) at northern Abukuma region, Japan, natural graphite, and copper oxide were heated up to 1900 ℃. In this heat treatment C-14 was extracted from melt quartz and natural graphite was oxidized with copper oxide to carbon carrier gas. In order to decrease background in our extraction system, natural graphite was used as precursor of carrier gas because natural graphite has low C-14 content and it is unlikely that isotopic exchange occurs with atmospheric carbon during storage. AMS measurement of natural graphite showed that the concentration was l.2x10⁵ (C-14 atoms/mg graphite). Based on this value, the extraction system blank was evaluated from results obtained with natural graphite and copper oxide, without quartz sample, to be (2-6)x10⁵ (C-14 atoms). AMS measurement of quartz samples showed that C-14 concentration raging form 5.7 x10⁴ to 1.5 x10⁵ (C-14 atoms /g quartz) and the erosion rate of roughly 1.8x10⁻³ cm/y, which was evaluated from analysis of Be-10 and Al-26., 石英試料(阿武隈高原北部において、表層から地下70cm（120 g/㎠）までの深さから採取したもの)に、天然石墨と酸化銅を添加して1900℃で加熱した。この加熱処理により、溶融石英からC-14を抽出し、また天然石墨を酸化銅で酸化し炭素の担体ガスに転換した。抽出処理において、モダンカーボンによる汚染を減らすために、天然石墨を担体ガスの前駆体として使用した。この理由は、天然石墨中はC-14含有量が無視でき、保管中に大気の炭酸ガスによって汚染をうけにくいためである。AMS測定の結果、天然石墨のC-14濃度は1.2x10⁵(atmos/mg)であり、この値を基に算出した溶融炉のC-14のバックグランドは(2~6)x10⁵個となった。石英試料中のC-14濃度は5.7x10⁴~1.5x10⁵(atoms/g)となり、削剥速度はBe-1OおよびAl-26の分析から得られた1.8x10⁻³ cm/yとおおよそ一致した。, 第22回名古屋大学年代測定総合研究センターシンポジウム平成21(2009)年度報告

An inter-laboratory comparison of ^C dating studies with accelerator mass spectrometty (AMS) were performed between two ^C facilities, Center for Chronological Research, Nagoya University and Mutsu Office, Aomori Research and Development Center, Japan Atomic Energy Agency. Both facilities are equipped with similar types of AMS system based on 3MV tandem accelerator manufactured by High Voltage Engineering Europe (HVEE), the Netherlands, that were introduced to each laboratory almost at the same time, around in 1996-1997. Two kinds of archeological samples used for the intercomparison were offered from the Education Board of Nirasaki City, Yamanashi prefecture. One part of them was a charred rice sample with known historical age, which was collected from the ruin of Shinpu-Jyo castle remains. The rice was charred when the castle was bumt in 1582, when the castle was abandoned by the lord, Katsuyori Takeda (1546-1582) during the battle against the combined military forces of Oda and Tokugawa families. Thus it is also a critical test of accuracy of the ^C measurements on samples with known age. The other samples were charred pyrenes of peach and nutshells of Japanese walnut collected from the Shukujiri-Daini-Iseki archeological site in Nirasaki city, Yamanashi Prefecture. Totally 12 samples were shared between the two laboratories, by dividing the individual charred pyrenes and nutshells into two pieces, i.e., the shared pieces were divided from a piece of pyrene or nutshell. Thus exactly consistent ^C results are expected for the divided pieces. The results from the two AMS laboratories were quite consistent within statistical uncertainties. In addition, calibrated ^C ages for the charred rice samples were also consistent with the historical age when the Shinpu-Jyo castle was bumt down.

熊本県泉村京丈山の石灰岩洞穴より, ニホンオオカミとされるほぼ完全な1個体分の全身骨格が1976年から1977年にかけての調査で発見された, 今回, この標本と国立科学博物館所蔵のニホンオオカミ全身骨格等と骨学的な比較検討を行い, あわせて放射性炭素(^C)法を使って, 骨の年代測定を行った.本研究では, 骨試料からタンパク質であるコラーゲンを抽出し, さらに骨の有機物としてより根元的であるアミノ酸集合体を抽出し, それらの物質に含まれる炭素について, 名古屋大学に設置されているタンデトロン加速器質量分析計を用いて年代測定を実施した.その結果, 京丈山ニホンオオカミ標本はがっちりした体格のニホンオオカミであり, 全身骨格がそろった標本としては本邦2例目の最古のものであることが確認された.また, アミノ酸集合体の^C年代は380±90yrBPと得られ, 室町から江戸初期に遡る可能性が示された., タンデトロン加速器質量分析計業績報告 Summaries of Researches Using AMS 1998 (平成10)年度