Comparison of secondary ion emission yields for poly-tyrosine between cluster and heavy ion impacts
✍ Scribed by K. Hirata; Y. Saitoh; A. Chiba; K. Yamada; Y. Takahashi; K. Narumi
- Publisher
- Elsevier Science
- Year
- 2010
- Tongue
- English
- Weight
- 263 KB
- Volume
- 268
- Category
- Article
- ISSN
- 0168-583X
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✦ Synopsis
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 þ 8 , 2.4 MeV C þ 8 , and 4.0 MeV C þ 8 ) and swift heavy monoatomic molybdenum ions (4.0 MeV Mo + and 14 MeV Mo 4+ ) 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 þ 8 impact increase with increasing incident energy within the energy range examined, (2) the 4.0 MeV C þ 8 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 þ 8 impact exhibits comparable emission yields to that for the Mo ion impact with higher incident energy (14 MeV Mo 4+ ). 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.