@article{oai:nagoya.repo.nii.ac.jp:00028042,
 author = {中村, 俊夫 and 南, 雅代 and 増田, 公明 and 小田, 寛貴 and 三宅, 芙紗 and 池田, 晃子 and 栗田, 直幸 and 山根, 雅子 and 西田, 真砂美 and 佐藤, 里名 and 酢屋, 徳啓 and 北川, 浩之 and Nakamura, Toshio and Minami, Masayo and Masuda, Kimiaki and Oda, Hirotaka and Miyake, Fusa and Ikeda, Akiko and Kurita, Naoyuki and Yamane, Masako and Nishida, Masami and Sato, Rina and Suya, Tokunori and Kitagawa, Hiroyuki},
 journal = {名古屋大学年代測定研究},
 month = {Mar},
 note = {An AMS system (Model 4130-AMS) dedicated to 14C measurements, built by High Voltage Engineering (HVE), B.V., the Netherlands, was delivered to Nagoya University in 1996/97. Acceptance tests of its performance on carbon-isotope-ratio measurements were completed in January of 1999, and a routine measurement started in mid-2000. The number of targets measured was 330, 1430, 2077, 1003, 1979, 1679, 1772, 1115, 1339, 866, 1300, 1701, 1449, 1634, 1351, 1741, 1156, 466, 900, and 1345 in each year from 1999 to 2018, respectively, and total number of targets measured by the end of December 2018 is 26,632. We briefly describe the maintenance processes of the Nagoya AMS system in the year of 2018. After suffering from severe machine problems in the last two years, the Tandetron AMS system at Nagoya University has also encountered a few problems in 2018. They are; (1) During the usual measurement of a graphite target, 12C^3+, 13C^3+ and 14C^3+ decreased gradually in the last half of its measurement time of 30 minutes. The plus-ion-beam intensity of 13C^3+ decreased from 200 nA to 5 nA in ten minutes, without any changes on its target current (corresponding to 13C^- injection current). We first checked all the parameter values of the power supplies to the AMS system, but we could not find any suspicious changes from their normal values. We finally concluded that something wrong has happened inside the accelerator tank, and decided to open the tank in 5 years after previously opening the tank. A timing belt to drive the power generator that supplies power to a turbomolecular pump was completely broken, and was dropped down to the bottom. The turbo molecular pump is important to keep good transmission from C^- to C^3+. We replaced the broken belt to a new one, and recovered a good transmission; (2) After a high-voltage spark, we could not apply high voltage to the accelerator. A control circuit board of supplying high voltage was checked and it was found out that the IC (IC3-AD669-BN) mounted on the electrical board B-5-41-205-0001 was out of work. We replace the board to a new one; (3) Carbon-ion current decreased as the result of full exhaustion of Cs in the ionizer system. Cleaning of whole ion source parts, and 1 g of Cs was filled to the reservoir tank of Cs sputtering ion source; (4) An air compressor was damaged after a long-term usage. We replace it to a new one; (5) A Faraday cup in front of the heavy ion detector was out of order and cannot be controlled to load in and put out from the beam line. We have checked the Faraday cup system and found out that the cup was disconnected from the pneumatic cylinder for controlling the cup position. We tighten the screw connecting the cup and air cylinder; (6) A computer system for controlling the AMS apparatus cannot work well, maybe by a heat problem. We re-greased the connecting area of CPU and the heat- sink unit for a better thermal conduction. We also replaced the hard disk presently used to the one of heavy-duty option. In spite of these problems, we can process totally 1345 graphite targets in 2018., 名古屋大学宇宙地球環境研究所では，1997年3月に完置されたHigh Voltage Engineering(HVE)社製Tandetron (Model4130-AMS)が放射性炭素（14C）測定に運用されている．イオン入射部にリコンビネーターを備えて，炭素の3種の同位体が同時に測定でき，導入された当時は14C測定において高性能を誇っていた．しかし，今になるとる14Cしか測定できない事が利用拡張の妨げになっている．同研究所は，2016年度から，「全国共同利用・共同研究拠点」に認定されており，「拠点」の重責を担っていくうえで，本装置は，特色のある，非常に重要な装置の一つと位置付けられている．2015年10月に年代測定総合研究センターから宇宙地球環境研究所へと組織改編された後，この装置のさまざまな故障が一挙に吹き出したが，これらの問題は，新研究所の理解と支援によりほぼ解決できた．2018年の1年間に発生した主な故障や保守作業を以下に示す．(1)試料の測定中に加速器から出力される炭素正イオン強度が次第に低くなった．5年ぶりに加速器タンクをオープンして点検したところ，加速器のターミナル部に設置されているターボ分子真空ポンプを駆動する発電機にメカニカルに動力を伝えるタイミングベルトが破断しているのが確認された（2018年1-2月）．(2)イオン源の分解洗浄，アイオナイザーの交換，Cs1gを充填（2018年6月末）．(3)エアコンプレッサーの故障と交換（2018年7月末）．(4)14C測定のルーティンの立ち上げにおいて，12C^3+,13C^3+は通常どおりの電流値を示すが，重イオン検出器での14C^3+の計数が全く無くなった．その原因として，検出器の直前にあるファラディ・カップをビームラインに出し入れするエアシリンダーの軸とファラディ・カップの軸受けのネジが緩んでおり，ファラディ・カップがビームラインに挿入されたままになっていた．（2018年8月初旬）．(5)装置制御用のプログラムがときおり停止し，またパソコンがフリーズするようになった．ハードディスクをサーバー用の製品に交換した（2018年8月末）．このような故障にもかかわらず，2018年には1345個のターゲットの測定を実施できた．},
 pages = {73--81},
 title = {名古屋大学タンデトロンAMS 14Cシステムの現状と利用（2018）},
 volume = {3},
 year = {2019}
}