An improved scanning electron microscope for opaque specimens

McMullan, D.

doi:10.1049/pi-3.1953.0064

Cited by 11 publications

(11 citation statements)

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“…Backscattered or secondary electrons are detected for imaging, so the surface of the sample is observed regardless of its thickness (McMullan, 1953;Reimer, 1998;Zworykin et al, 1942). This unique characteristic has allowed development of the SEM in two different directions: the environmental SEM (Danilatos, 1981(Danilatos, , 1991Robinson, 1975) and the environmental cell (Thiberge et al, 2004a,b).…”

Section: Introductionmentioning

confidence: 99%

Reprint of: Atmospheric scanning electron microscope observes cells and tissues in open medium through silicon nitride film

Nishiyama

Suga

Ogura

et al. 2010

Journal of Structural Biology

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Direct observation of subcellular structures and their characterization is essential for understanding their physiological functions. To observe them in open environment, we have developed an inverted scanning electron microscope with a detachable, open-culture dish, capable of 8 nm resolution, and combined with a fluorescence microscope quasi-simultaneously observing the same area from the top. For scanning electron microscopy from the bottom, a silicon nitride film window in the base of the dish maintains a vacuum between electron gun and open sample dish while allowing electrons to pass through. Electrons are backscattered from the sample and captured by a detector under the dish. Cells cultured on the open dish can be externally manipulated under optical microscopy, fixed, and observed using scanning electron microscopy. Once fine structures have been revealed by scanning electron microscopy, their component proteins may be identified by comparison with separately prepared fluorescence-labeled optical microscopic images of the candidate proteins, with their heavy-metal-labeled or stained ASEM images. Furthermore, cell nuclei in a tissue block stained with platinum-blue were successfully observed without thin-sectioning, which suggests the applicability of this inverted scanning electron microscope to cancer diagnosis. This microscope visualizes mesoscopic-scale structures, and is also applicable to non-bioscience fields including polymer chemistry.

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Section: Introductionmentioning

confidence: 99%

Reprint of: Atmospheric scanning electron microscope observes cells and tissues in open medium through silicon nitride film

Nishiyama

Suga

Ogura

et al. 2010

Journal of Structural Biology

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“…(5). McMullan (1953) expressed k as this ratio: k = d n e /√( n e ), where d n e is the signal excursion due to the object compared to the background, i.e. the barely discernible difference in electron count, and is the noise or fluctuation in counts, assuming Poisson statistics.…”

Section: Theorymentioning

confidence: 99%

Visibility of objects in computer simulations of noisy micrographs

Bright

Newbury

Steel

1998

Journal of Microscopy

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Thresholds of visibility for objects in images with random pixel noise are predicted in terms of the signal-to-noise ratio. From trials with volunteers marking test images, we determined visibility thresholds of objects obscured by random pixel noise. The test images had objects with a variety of simple shapes and relatively little internal structure. Aside from the noise, the background of the test images was smooth and featureless. We extend the threshold signal-to-noise ratio measurements of Rose and others to a variety of object sizes and shapes. For objects with areas less than a disc subtending 2 degrees at the eye, visibility depends on the averaged difference in intensity from background, the noise level and the number of pixels in the object. Visibility does not seem to depend on object shape.

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“…The performance of the electron optics seemed adequate for the initial experiments on SEM and efforts were now directed to providing auxiliary equipment: scan generators, video channel, and monitors, all of which had again to be built in-house. From the outset the scanning equipment was quite elaborate: mains-locked interlaced scans, non-linear amplifier for gamma control, beam blanking for DC restoration, and a separate cathode-ray tube for photographic recording (McMullan, 1952(McMullan, , 1953b. It turned out that this effort was well worthwhile because it ensured that from the start the quality of the SEM images was not limited by the electronic circuits.…”

Section: The C a M B R I D G E Sem 1948-53mentioning

confidence: 99%

Recollections of the early days of SEM in the Cambridge University Engineering Department, 1948–53

McMullan

1985

Journal of Microscopy

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SUMMARY After a brief survey of the early development of the scanning electron microscope in Germany and the U.S.A., the paper describes the work on the subject that was carried out in the Cambridge University Engineering Department, particularly in the years 1948–53. This and later work led directly to the Stereoscan SEM marketed by the Cambridge Instrument Company in 1965. The paper is illustrated with a number of micrographs produced by early scanning electron microscopes.

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An improved scanning electron microscope for opaque specimens

Cited by 11 publications

References 0 publications

Reprint of: Atmospheric scanning electron microscope observes cells and tissues in open medium through silicon nitride film

Reprint of: Atmospheric scanning electron microscope observes cells and tissues in open medium through silicon nitride film

Visibility of objects in computer simulations of noisy micrographs

Recollections of the early days of SEM in the Cambridge University Engineering Department, 1948–53

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