@article{oai:nagoya.repo.nii.ac.jp:00011606, author = {南, 雅代 and Minami, Masayo 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 = {Terrestrial age of meteorites gives us important information to estimate the terrestrial history of the meteorites. With the advent of AMS, the required sample mass of meteorite for measurement has been reduced as small as 0.1g. As a result, many more ^<14>C measurements have been performed intensively by the Toronto AMS group, Canada, the Arizona AMS group, USA, and so on. In Japan, AMS ^<14>C measurements of meteorites have been scarcely performed, to our regret. We are now at the early stage of the program for studying ^<14>C activities in meteorites, and constructing a system to extract ^<14>C from meteorites, in a similar method used by the Arizona group. A meteorite powder sample mixed with pure iron chips is combusted in a RF furnace (Leco HF-10) in the presence of purified carbon-free oxygen in a closed vacuum-tight glass line system. The sample gases evolved are passed through MnO_2 and Pt/CuO traps, and then the CO_2 is separated in a liq.N_2 trap, by pumping out oxygen completely. The amount of ^<14>CO_2 is determined by a pressure transducer in a certain volume and diluted with a known amount of ^<14>C^free CO_2. The total CO_2 is graphitized by reducing with hydrogen in a Fe-powder catalyst and the produced graphite is measured of its ^<14>C concentration with a Tandetron accelerator mass spectrometer at the Dating and Materials Research Center, Nagoya University. Extraction yields of CO_2 using the above method which employs RF melting of steel standards of known carbon content were about 90%. The new extraction procedure gave higher extraction yields and older ^<14>C ages than those using the old extraction method. Carbon yields of two Antarctic meteorites (Y-75102 and ALH-77294), however, were significantly low, and the carbon-14 terrestrial ages for the meteorites were different from the reported values. The results might be caused by imperfect combustions of the meteorites and high blanks from the crucible with iron chips alone. Further studies are needed to improve analytical techniques., 第12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11 (1999年度)報告 名古屋大学タンデトロン加速器質量分析計第1号機の研究実績と1号機,2号磯の利用計画}, pages = {100--112}, title = {南極隕石の落下<14>^C年代測定の試み}, volume = {11}, year = {2000} }