Comparison of secondary ion emission yields for poly-tyrosine between cluster and heavy ion impacts

クラスターイオンと重イオンのポリチロシンへの照射における2次イオン放出量の比較

平田 浩一*; 齋藤 勇一; 千葉 敦也; 山田 圭介; 高橋 康之; 鳴海 一雅

Hirata, Koichi*; Saito, Yuichi; Chiba, Atsuya; Yamada, Keisuke; Takahashi, Yasuyuki; Narumi, Kazumasa

Emission yields of secondary ions necessary for the identification of poly-tyrosine were compared for incident ion impacts of energetic cluster ions (0.8 MeV C, 2.4 MeV C, and 4.0 MeV C) and swift heavy monoatomic molybdenum ions (4.0 MeV Mo and 14 MeV Mo) with similar mass to that of the cluster by time-of-flight secondary ion mass analysis combined with secondary ion electric current measurements. The comparison revealed that (1) secondary ion emission yields per C impact increase with increasing incident energy within the energy range examined, (2) the 4.0 MeV C impact provides higher emission yields than the impact of the monoatomic Mo ion with the same incident energy (4.0 MeV Mo), and (3) the 2.4 MeV C impact exhibits comparable emission yields to that for the Mo ion impact with higher incident energy (14 MeV Mo). Energetic cluster ion impacts effectively produce the characteristic secondary ions for poly-tyrosine, which is advantageous for highly sensitive amino acid detection in proteins using time-of-flight secondary ion mass analysis.