Phase TEM for biological imaging utilizing a Boersch electrostatic phase plate: theory and practice

被引：26

作者：

Shiue, Jessie ^{[1
]}

Chang, Chia-Seng ^{[1
]}

Huang, Sen-Hui ^{[4
]}

Hsu, Chih-Hao ^{[4
]}

Tsai, Jin-Sheng ^{[3
]}

Chang, Wei-Hau ^{[2
]}

Wu, Yi-Min ^{[2
]}

Lin, Yen-Chen ^{[2
]}

Kuo, Pai-Chia ^{[1
]}

Huang, Yang-Shan ^{[1
]}

Hwu, Yeukuang ^{[1
,3
]}

Kai, Ji-Jung ^{[4
]}

Tseng, Fan-Gang ^{[4
]}

Chen, Fu-Rong ^{[1
,3
,4
]}

机构：

[1] Acad Sinica, Inst Phys, Nankang 11529, Taiwan

[2] Acad Sinica, Inst Chem, Nankang 11529, Taiwan

[3] Natl Synchrotron Radiat Res Ctr, Hsinchu 30076, Taiwan

[4] Natl Tsing Hua Univ, Dept Engn & Syst Sci, Hsinchu 30043, Taiwan

来源：

JOURNAL OF ELECTRON MICROSCOPY | 2009年 / 58卷 / 03期

关键词：

phase TEM; Beorsch phase plate; Zernike phase plate; electrostatic phase plate; biological imaging; phase contrast; CONTRAST; MICROSCOPES; WAVES;

D O I：

10.1093/jmicro/dfp006

中图分类号：

TH742 [显微镜];

学科分类号：

摘要：

A Boersch electrostatic phase plate (BEPP) used in a transmission electron microscope (TEM) system can provide tuneable phase shifts and overcome the low contrast problem for biological imaging. Theoretically, a pure phase image with a high phase contrast can be obtained using a BEPP. However, a currently available TEM system utilizing a BEPP cannot achieve sufficiently high phase efficiency for biological imaging, owing to the practical conditions. The low phase efficiency is a result of the blocking of partial unscattered electrons by BEPP, and the contribution of absorption contrast. The fraction of blocked unscattered beam is related to BEPP dimensions and to divergence of the illumination system of the TEM. These practical issues are discussed in this paper. Phase images of biological samples (negatively stained ferritin) obtained by utilizing a BEPP are reported, and the phase contrast was found to be enhanced by a factor of similar to 1.5, based on the calculation using the Rose contrast criterion. The low gain in phase contrast is consistent with the expectation from the current TEM/BEPP system. A new generation of phase TEM utilizing BEPP and designed for biological imaging with a high phase efficiency is proposed.

引用

页码：137 / 145

页数：9

共 18 条

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