Intensity diffraction tomography with fixed detector plane

Daxin Shi

doi:10.1117/1.2799088

Configured detectors in STEM holography

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100129541 ◽

1992 ◽

Vol 50 (2) ◽

pp. 982-983

Author(s):

Shi-Yao Wang ◽

Marian Mankos ◽

J. M. Cowley

Keyword(s):

Plane Wave ◽

Interference Pattern ◽

Sensitivity Function ◽

Objective Lens ◽

Detector Plane ◽

Detector Sensitivity ◽

Preliminary Work ◽

Fixed Detector

In Gabor's in-line holography, the transmitted plane wave and the beam diffracted by the specimen form an interference pattern (hologram). In a STEM instrument, when the incident probe is scanning over the specimen, the hologram translates across the illuminated portion of the detector plane. The signal produced by the detector can be represented by integrating the product of the hologram with some detector sensitivity function. It had be pointed out long ago by Veneklasen that scanning the hologram over a fixed detector has in effect performed a reconstruction of the hologram simultaneously, and with some specially designed detector the aberration introduced by the objective lens is correctable. This scheme has been reraised recently and some preliminary work will be reported here.

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Imaging and diffraction modes in Scanning Transmission Electron Microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100144814 ◽

1986 ◽

Vol 44 ◽

pp. 684-687

Author(s):

J. M. Cowley ◽

R. Glaisher ◽

J. A. Lin ◽

H.-J. Ou

Keyword(s):

Scanning Transmission Electron Microscopy ◽

High Efficiency ◽

Fiber Optic ◽

Image Intensifier ◽

Detector System ◽

Detector Plane ◽

Secondary Electrons ◽

Transmission Electron ◽

Scanning Transmission ◽

Special Detector

Some of the most important applications of STEM depend on the variety of imaging and diffraction made possible by the versatility of the detector system and the serial nature, of the image acquisition. A special detector system, previously described, has been added to our STEM instrument to allow us to take full advantage of this versatility. In this, the diffraction pattern in the detector plane may be formed on either of two phosphor screens, one with P47 (very fast) phosphor and the other with P20 (high efficiency) phosphor. The light from the phosphor is conveyed through a fiber-optic rod to an image intensifier and TV system and may be photographed, recorded on videotape, or stored digitally on a frame store. The P47 screen has a hole through it to allow electrons to enter a Gatan EELS spectrometer. Recently a modified SEM detector has been added so that high resolution (10Å) imaging with secondary electrons may be used in conjunction with other modes.

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