Transfer doublet and an elaborated phase plate holder for 120 kV electron-phase microscope
Transfer doublet and an elaborated phase plate holder for 120 kV electron-phase microscope
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DOI：
10.1093/jmicro/dfi049
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发表时间：
2005-01-01
期刊：
影响因子：
--
通讯作者：
Nagayama, K
中科院分区：
文献类型：
--
作者：
Hosokawa, F;Danev, R;Nagayama, K
研制了一种用于120 kV透射电子显微镜（TEM）的Zernike型无定形碳膜位相板。膜的厚度导致散射电子经历π/2相移。轴向电子穿过相位板的中心孔。TEM用额外的双透镜进行了修改，这使得在应用相位板时具有更大的灵活性。双合透镜将图像从后焦平面转移到物镜透镜下方的平面上，在该平面上可以使用特殊的相位板保持器、抗污染器和其他必要的装置。相位板中的中心孔的直径为1 mm。使用与样品台中相同的机械系统将轴向光束对准到孔中。研究了使用加热保持器来保护相位板免受污染和随之而来的充电。显示了使用和不使用相位板的无定形碳的比较衍射图，证明了当使用相位板时，相位对比调制从正弦函数到余弦函数的变化。利用相位板对生物样品进行了成像实验，实验结果表明，余弦传递函数能有效地增强生物样品的对比度。膜的厚度导致散射电子经历π/2相移。轴向电子穿过相位板的中心孔。TEM用额外的双透镜进行了修改，这使得在应用相位板时具有更大的灵活性。双合透镜将图像从后焦平面转移到物镜透镜下方的平面上，在该平面上可以使用特殊的相位板保持器、抗污染器和其他必要的装置。相位板中的中心孔的直径为1 μ m。使用与样品台相同的机械系统将轴向光束对准孔。研究了使用加热保持器来保护相位板免受污染和随之而来的充电。显示了使用和不使用相位板的无定形碳的比较衍射图，证明了当使用相位板时，相位对比调制从正弦函数到余弦函数的变化。使用相位板采集的生物标本的图像和对比度增强由于余弦传递函数清楚地表明。
A Zernike-type phase plate, which consisted of an amorphous carbon film, was developed for a 120 kV transmission electron microscope (TEM). The thickness of the film causes the scattered electrons to experience a pi/2 phase shift. The axial electrons pass through the central hole of the phase plate. The TEM was modified with an additional lens doublet, which allowed more flexibility in applying the phase plates. The doublet transfers the image from the back focal plane to a plane below the objective lens where a special phase plate holder, anticontaminator, and other necessary devices could be employed. The diameter of the central hole in the phase plate was 1 mm. The same mechanical system as in the specimen stage is used to align the axial beam into the hole. The use of a heating holder to protect the phase plate from contamination and consequential charging was investigated. Comparative diffractograms of amorphous carbon are shown with and without using a phase plate, demonstrating the change in phase contrast modulation from a sine to a cosine function when a phase plate is used. Images of biological specimens acquired using a phase plate are presented and the contrast enhancement due to the cosine transfer function is clearly demonstrated.A Zernike-type phase plate, which consisted of an amorphous carbon film, was developed for a 120 kV transmission electron microscope (TEM). The thickness of the film causes the scattered electrons to experience a pi/2 phase shift. The axial electrons pass through the central hole of the phase plate. The TEM was modified with an additional lens doublet, which allowed more flexibility in applying the phase plates. The doublet transfers the image from the back focal plane to a plane below the objective lens where a special phase plate holder, anticontaminator, and other necessary devices could be employed. The diameter of the central hole in the phase plate was 1 mu m. The same mechanical system as in the specimen stage is used to align the axial beam into the hole. The use of a heating holder to protect the phase plate from contamination and consequential charging was investigated. Comparative diffractograms of amorphous carbon are shown with and without using a phase plate, demonstrating the change in phase contrast modulation from a sine to a cosine function when a phase plate is used. Images of biological specimens acquired using a phase plate are presented and the contrast enhancement due to the cosine transfer function is clearly demonstrated.