Transmission properties of C ions through micro- and nano-capillaries

Tsuchida, Hidetsugu*; Majima, Takuya*; Tomita, Shigeo*; Sasa, Kimikazu*; Narumi, Kazumasa; Saito, Yuichi; Chiba, Atsuya; Yamada, Keisuke; Hirata, Koichi*; Shibata, Hiromi*; Ito, Akio*

Applying the beam-focusing method with capillaries to C projectiles in the velocity range between 0.14 and 0.2 a.u., transmission properties of C ions through two different types of capillaries are studied: (1) a borosilicate-glass single microcapillary with an outlet diameter of 5.5 m, and (2) an AlO multicapillary foil with approximatey 70-nm pores in diameter and a high aspect ratio of approximately 750. Transmitted-particle compositions are measured with the electrostatic-deflection method combined with a two-dimensional position-sensitive detector. In the experiments with the single microcapillary, the main transmitted component is found to be primary C ions, which are focused in the area equal to the capillary outlet diameter. The other components are charge-exchanged C ions and charged or neutral fragments (fullerene-like C and small C particles), and their fractions decrease with decreasing projectile velocity. Similar results are obtained in the experiments with the multicapillary foil. It is concluded from the relative transimission fractions of more than 80% that the C transmission fraction is considerably high for both types of the capillaries in the present velocity range.