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- ivylysky 2017-10-10 19:32:57
- 電子顯微鏡的分辨本領(lǐng)由于受到電子透鏡球差的限制,人們力圖像光學透鏡那樣來減少或消除球差。但是,早在1936年Scherzer就指出,對于常用的無空間電荷且不隨時間變化的旋轉(zhuǎn)對稱電子透鏡,球差恒為正值。在40年代由于兼顧電子物鏡的衍射和球差,電子顯微鏡的理論分辨本領(lǐng)約為0.5nm。校正電子透鏡的主要像差是人們長期追求的目標。經(jīng)過50多年的努力,1990年Rose提出用六極校正器校正透鏡像差得到無像差電子光學系統(tǒng)的方法。Z近在CM200ST場發(fā)射槍200kV透射電鏡上增加了這種六極校正器,研制成世界上diyi臺像差校正電子顯微鏡。電鏡的高度僅提高了24cm,而并不影響其它性能。分辨本領(lǐng)由0.24nm提高到0.14nm。在這臺像差校正電子顯微鏡上球差系數(shù)減少至0.05mm(50μm)時拍攝到了GaAs〈110〉取向的啞鈴狀結(jié)構(gòu)像,點間距為0.14nm。
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- 球差校正透射電鏡,有高手介紹一下么
- 透射電鏡怎么校正
透射電鏡(Transmission Electron Microscope, TEM)作為一種精密的科學儀器,廣泛應用于材料科學、生命科學、納米技術(shù)等領(lǐng)域,其高分辨率的成像能力使其成為觀察細微結(jié)構(gòu)的重要工具。為了保證透射電鏡獲得準確的成像結(jié)果,校正是不可忽視的一步。本文將探討透射電鏡的校正方法、常見問題及其解決方案,旨在幫助科研人員優(yōu)化儀器性能,獲得更加精確的實驗數(shù)據(jù)。
透射電鏡的校正過程包括多個方面,主要涉及電子束的調(diào)整、透鏡的對準以及探測器的優(yōu)化等。電子束的校正是確保圖像清晰度和分辨率的關(guān)鍵。通過調(diào)整電子束的聚焦狀態(tài),避免出現(xiàn)光斑或散射現(xiàn)象,可以提高成像質(zhì)量。透鏡的校正同樣至關(guān)重要,特別是在高分辨率成像時,任何微小的偏差都可能導致圖像模糊。因此,透射電鏡需要定期進行透鏡的對準和優(yōu)化。探測器的校正也影響到圖像的對比度和亮度,確保信號傳輸?shù)木_性是校正過程中不可或缺的一部分。
為了進一步提高透射電鏡的性能,很多現(xiàn)代儀器還配備了自動校正系統(tǒng),這些系統(tǒng)能夠在實驗過程中自動監(jiān)控和調(diào)整儀器狀態(tài)。即便如此,操作人員仍需定期進行手動校正,確保儀器狀態(tài)始終處于佳水平。值得注意的是,透射電鏡的校正不僅依賴于儀器本身的硬件配置,還需要根據(jù)樣品的類型、成像需求等因素做出相應的調(diào)整。
透射電鏡的校正是一個系統(tǒng)性的過程,涉及多個層面。通過細致的調(diào)整和優(yōu)化,不僅可以提高圖像的清晰度和準確性,還能延長儀器的使用壽命??蒲腥藛T應深入了解校正原理,掌握各項操作技巧,從而充分發(fā)揮透射電鏡在科學研究中的優(yōu)勢。
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