Properties of fast carbon cluster microbeams produced with a tapered capillary

NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS

卷:293

Article

Tsuchida, Hidetsugu^1,2  Tomita, Shigeo³  Nishimura, Kazushige²  Murakoshi, Ryohei²  Naitoh, Masahiro²  Sasa, Kimikazu⁴  Ishii, Satoshi⁴  Yogo, Akifumi⁵  Itoh, Akio^1,2 

[1] Kyoto Univ, Quantum Sci & Engn Ctr, Kyoto 6110011, Japan

[2] Kyoto Univ, Dept Nucl Engn, Kyoto 6068501, Japan

[3] Univ Tsukuba, Inst Appl Phys, Tsukuba, Ibaraki 3058573, Japan

[4] Univ Tsukuba, Tsukuba, Ibaraki 3058577, Japan

[5] Japan Atom Energy Agcy, Photomed Res Ctr, Kyoto 6190215, Japan

关键词: Carbon clusters;    Microbeam;    Tapered glass capillary optics;   

DOI  :  10.1016/j.nimb.2012.09.035

来源: Elsevier

【 摘 要 】

We study the transmission properties of fast cluster ions (C-n(+) (n = 2-4) with velocities ranging from 0.89 to 1.79 a.u.) through a single tapered capillary with an outlet diameter of 13.7 mu m. We investigate the projectile-velocity dependence of the transmission fraction from the measurements of transmitted particle energy spectra. It is found that the non-fragmentation fraction of C-2(+) projectiles increases with decreasing velocity, indicating that fragmentation occurs mainly via close collisions with the surfaces of the capillary wall. For C-n(+) (n = 2-4) ions with the same incident velocity, the cluster-size dependence of the non-fragmentation fraction shows even odd alternation, implying that the fraction includes contributions from stable clusters surviving the grazing scattering process at the capillary surface. We also find that the angular distribution of transmitted particles is narrower for cluster projectiles compared with atomic projectiles. (C) 2012 Elsevier B.V. All rights reserved.

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