Challenges and opportunities in high-precision Be-10 measurements at CAMS
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- 作者：Dylan H. Rood ; Sarah Hall ; Thomas P. Guilderson ; Robert C. Finkel ; Thomas A. Brown
- 关键词：AMS ; Ion source ; Efficiency ; Beryllium-10
- 刊名：Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms
- 出版年：2010
- 出版时间：April 2010
- 年：2010
- 卷：268
- 期：7-8
- 页码：730-732
- 全文大小：343 K
文摘
We determined the overall efficiency for 10Be of the high-intensity LLNL modified Middleton cesium sputter source in combination with the CAMS FN mass spectrometer. BeO− ionization efficiency is >3 % . Charge exchange efficiency including transmission through the tandem for 7.5 MeV Be+3 is 34 % , resulting in a total system efficiency of just over 1 % . At this efficiency and with very low backgrounds, we estimate our detection limit to be 1000 10Be atoms. Cathodes prepared with only 80 μg of 9Be show only an 33 % reduction in 9Be beam current compared to a sample with 200 μg. These same samples, prepared from 07KNSTD1032 standard material, contained 1 × 107 and 5 × 106 10Be atoms and exhibited similar ionization and total system efficiency. These results demonstrate the feasibility of pursuing applications that require precise measurement of samples with low 10Be concentrations and/or small sample size.