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http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/43161
標題: | 滅塵者之初步測試 The Initial Testing of DustBuster |
作者: | En-Chuan Huang 黃恩泉 |
指導教授: | 李太楓(Typhoon Lee) |
關鍵字: | 質譜儀,星塵計畫,同位素,太陽系,滅塵者, TOF,Star Dust Mission,mass spectrometer,DustBuster,isotope,nucleosynthesis, |
出版年 : | 2009 |
學位: | 碩士 |
摘要: | 為了研究早於太陽系之稀有微米尺寸粒子,我們藉由美國阿岡國家實驗室的設計已經成功建置了一個新型態的二次中性粒子飛行時間質譜儀——滅塵者。滅塵者旨在分析隕石粉塵與星塵計畫返回之慧星粉塵中之大的同位素偏差。在質量解析度1000左右時,我們的標本使用效率可以達到5%,而原先的設計為30%,在相似儀器當中曾經達到最高的效率為20%,因此,我們需要進一步的調整來達到高的使用效率。我們已經測試了許多地球標本,包含了鉬、鈦、鎳與鈦鐵礦、楔石、金紅石、黃鐵礦、鎂橄欖石和方柱石,同時也嘗試了我們第一個隕石的標本。在鈦鐵礦中最好的情況下,1000秒的實驗中,鈦同位素46比48的偏差的一個標準差只有0.7%,是統計誤差的兩倍以內,並且在氧化鈦形式當中的鈦46的同位素比值的一個標準差小於1%。然而氫化並氫氧化的情形與雜質的干擾有待解決。 To fit the need of best exploitation of one-of-a-kind tiny (several μms) pre-solar dust grains, we have finished the construction of DustBuster, a new generation of Secondary Neutral Time of Flight Mass Spectrometer (TOF-SNMS) based on the design of Argonne National Lab. It aims to analyze large isotope variations expected for pre-solar dust grains in meteorite and in comet sample returned by Star Dust Mission. At a mass resolution around 1000, our useful yield (ions detected/atoms sputtered) has reached nearly 5%, while the design goal is 30% and the best achieved so far was 20 % in a similar instrument. Therefore, some further fine tuning is needed to achieve higher sensitivity. We have tested several terrestrial samples, such as Mo, Ti, Ni, ilmenite, titanite, rutile, pyrite, forsterite and melilite. We have also attempted to analyze our first meteorite sample. In our best cases in ilmenite, isotopic variation in 46TiO/48TiO the within run (1000 sec) scatter was only 0.7% (1σ), which is within factor of 2 of statistics limit. And the reproducibility in the case of 46TiO can be as good as ≦1%. However, hydride/hydroxide and low-level contamination problems wait still to be solved. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/43161 |
全文授權: | 有償授權 |
顯示於系所單位: | 物理學系 |
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