Monday, 5 September 2005

This presentation is part of: Poster Session I

Status and plans for AMS at NIES-TERRA

Minoru Yoneda1, Hikaru Uno1, Atsushi Tanaka1, Takashi Uehiro1, Ryo Suzuki2, Toshiyuki Kobayashi3, Chiaki Kobayashi3, Masao Uchida4, Yasuyuki Shibata1, and Masatoshi Morita1. (1) Environmental Chemistry Division, National Institute for Environmental Studies, Onogawa 16-2, Tsukuba, 305-8506, Japan, (2) Environmental Research Center, Ltd., Tsukuba, 305-0857, Japan, (3) Hakuto Co., Ltd., Shinjuku, Tokyo, 160-8910, (4) Institute of Oceanographic Research for Global Changes(IORGC), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka 237-0061, Japan

The AMS facility at the National Institute for Environmental Studies, NIES-TERRA, is in operation since 1997 [1-3]. This facility that was constructed by National Electrostatics Corp., U.S.A, consists of two kinds of ion sources (SNICS and MGF-SNICS), 15SDH-2 accelerator, and two detectors (time-of-flight and E-delta E detectors). Although two detectors were designed for measuring multiple nuclides (i.e. 129I, 10Be and 14C) respectively [4], most of machine time has been dedicated to routine measurements of 14C by using SNICS and E-delta E detector. NIES-TERRA has produced more than 4000 measurements of unknown samples including not only environmental samples (methane, airborne particulate matter, marine and pond sediments, peat cores, coral skeletons and so on) but also some of archaeology, anthropology and geography. The number of measurements is still increasing.

In the summer of 2005, the E-delta E detector will be converted to the same type as SUERC AMS for the routine measurement of 14C, 10Be, 36Cl, and 129I [5]. Its new design makes it possible to switch the target without breaking the vacuum of the system. Hence, the effective measurement of 10Be as well as 14C is essential for some newly established projects including cosmogenic nuclides in a long Antarctic ice core. Furthermore, an improved design of the continuous-flow preparation system was drawn out for acid and base reactions. New circulation vessel can work effectively without tube clogging. Then, graphite targets are prepared by using a combustion system with an elemental analyzer and cryogenic traps [3]. Some preliminary evaluations for these improvements will be shown.

[1] Kume et al., Nucl. Instrum. Meth. B 123, 31 (1997).

[2] Tanaka et al., Nucl. Instrum. Meth. B 172, 107 (2000).

[3] Yoneda et al., Nucl. Instrum. Meth. B 223-224, 116 (2004).

[4] Shibata et al., Nucl. Instrum. Meth. B 123, 554 (1997).

[5] Freeman et al., Nucl. Instrum. Meth. B 223-224, 195 (2004).



Web Page: www.nies.go.jp/chem/terra/index.html

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