bluuebunny/crossref_metadata_2025 huggingface dataset:
An atmospheric scanning electron microscope (ASEM)
Authors: Danilatos G. D.
Published: August 2011

A new detection configuration for the Scanning Electron Microscope (SEM) has been devised, which allows the imaging of the surfaces of a specimen in the open room, i.e., at atmospheric pressure. Such a device gives rise to a new microscope: the Atmospheric Scanning Electron Microscope (ASEM). In this configuration, a backscattered electron detector is placed between the pressure limiting aperture and the electron column. The electron beam passes through the final aperture, reaches the sample in the open room and the backscattered electrons passing through the same final aperture reach the detector. This principle has been tested and the result reported.
Electron beam blanking systems
Authors: Fujioka H. , Ura K.
Published: August 2011

Electron beam blanking in the scanning electron microscope (SEM) by deflection over a chopping aperture is reviewed. The first part is concerned with electron beam deflection structures and driving methods, the second part with electron optics of deflection blanking systems in the SEM.
Electron beam testing: Methods and applications
Authors: Feuerbaum H. P.
Published: August 2011

There are eight e‐beam methods of testing integrated circuits. The principle and performance of the various methods will be discussed in this paper. The performance criteria are voltage resolution and the frequency range in which voltage changes can be detected. From this it is possible to decide which methods are best suited for testing the various IC types available today.
A double detector system for BSE and SE imaging
Authors: Autrata R.
Published: August 2011

The double detector system described here is a simple device suitable for any SEM. It permits efficient imaging of specimen surfaces in either the secondary electron (SE) or backscattered electron (BSE) mode. The BSE detector is an annular single‐crystal scintillator made of yttrium aluminium garnet (YAG) and the SE detector has a scintillator of the same material. Both detectors have their own light guides which are connected to a single photomultiplier. The choice of signal is made with a mechanical diaphragm mounted on a flange between the light guide and the photomultiplier. The SE detector may be replaced by a second BSE detector to allow the detection of “low” take‐off angle BSEs to provide information which differs from that given by the annular BSE detector which operates to detect BSEs with a “high” take‐off angle. In this way it is possible to image either material or topographic contrast with high resolution and to take advantage of the choice of detected electrons.
Quantitation of shrinkage during preparation for scanning electron microscopy: Human lung
Authors: Bastacky J. , Hayes T. L. , Gelinas R. P.
Published: August 2011

Human lung tissue is found to shrink considerably with preparation for SEM. Fifty‐one blocks of glutar‐aldehyde‐fixed and inflated lung, approximately 2.5 cm × 2.5 cm × 1 cm, shrank a mean of 19% (± 4.0% SD) linear dimension through post fixation, dehydration and critical point drying. Shrinkage with fixation was not measured. Blocks of lung were observed to shrink equally in length (L) and width (W), L = 19.4% ± 2.7 SD, W = 19.0% ± 4.0 SD. Final shrinkage was the same whether samples were dehydrated in acetone or ethanol, although with acetone more of the shrinkage occurred during the dehydration process and less occurred during critical point drying.
Scanning deep level transient spectroscopy (SDLTS)
Authors: Breitenstein O. , Heydenreich J.
Published: August 2011

Scanning Deep Level Transient Spectroscopy (SDLTS) is a current SEM technique for the detection of the local distribution of deep level centres in semiconductors. It is based on the application of the widely used Deep Level Transient Spectroscopy (DLTS), which enables capacitance changes (or current changes) to be measured in a space charge structure after an excitation pulse as a function of the temperature. This makes it possible to detect the energy levels and the concentration of electronic states in the band gap. By means of scanning DLTS–i.e. the excitation of the levels by an electron probe–deep level states can be investigated with a spatial resolution of a few microns. Scanning the pulsed electron beam (at a temperature selected according to an interesting energy level) yields an SDLTS image. Based on the general principle of the measurement and on the necessary instrumentation the practice of the SDLTS signal generation analysis is presented and experimental examples are discussed.
Electron optical property of a charged foil, observed with a transmitted electron detector device in an SEM
Authors: Wurster R.
Published: August 2011

Experimental evidence is presented for the electron optical behaviour of a charged foil area, using the transmitted electron detection device of the scanning electron microscope JSM 50 A (JEOL). The primary electron beam scanning a thin pioloform foil on the one hand produces a charged foil region which on the other hand acts as an electron lens to the primary and scattered electrons.

Scanning electron microscopical investigations of air particulates in the submicron size range can be eased by using a transmitted electron detection device both of the bright and dark field operation mode. The image contrast thus may be improved by orders of magnitude, also allowing on line operation of an image analysis system. Using a special preparation technique, depositing the particles on a thin supporting foil which is also used for LAMMA analysis – Wieser et al. 1980, the x‐ray spectra of single particles provided by an energy dispersive x‐ray spectrometer may be quantitatively interpreted on the basis of the peak‐to‐background method (Statham and Pawley 1978, Small et al. 1979).

Figure 1 shows a schematic of the transmission detector device of the JSM 50 A when operated in the dark field mode. Geometrical dimensions and apertures also are given in Fig. 1. The dark field diaphragm (DFD) on the optical axis of the microscope blocks all electrons (primary electrons and scattered electrons) within an angle of about 10−2 rad from contributing to the video signal. As long as magnifications above about 350 × are used the primary electron beam hits the DFD thus yielding a transmission scanning electron micrograph in dark field mode. Below this limit or above the corresponding maximal scanning angle (about 7 × 10−3 rad) of the primary electron beam the rim of the DFD becomes visible in the displayed image as shown in Fig. 2a. At the same magnification Figure 2b shows the sharpened contours of the DFD as obtained by focussing the primary electron beam to the plane of the DFD by lowering the objective lens excitation. By means of the thin bar attached to the DFD (left hand upper corner of Fig. 2b) the DFD may be centered to the optical axis or exchanged to the bright field aperture.

Looking to the circular center of Fig. 2a, we recognize the black grid bars and a few black particles whereas the supporting foil looks bright. No video signal can be obtained, because both the grid bars, and to a lesser extent the particles, are not transparent to the primary electrons of 15 keV energy. On the other hand all electrons scattered by the thin foil to an angle of more than 10−2 rad are seen by the scintillator and hence accumulate a measurable video signal: This is also favoured by the large solid angle outside the DFD, which is about 30 times the solid angle of the DFD itself.
A BSE scintillation detector in the (S)TEM
Authors: Autrata R. , Walther P. , Kriz S. , Müller M.
Published: August 2011

A single crystal YAG: Ce3+ annular scintillator axially placed in a movable light guide forms the essential part of a new BSE detector. Comparison of properties of this detector with those of a semiconductor detector is made. The bandwidth, signal‐to‐noise ratio, capacitance effects, and relative efficiency are parameters which favour the scintillation detector. Its disadvantage is that it must be equipped with a photomultiplier and a light guide. The position of the scintillator above the specimen permits efficient detection at a large collection angle of BSE. For normal beam incidence, the signal homogeneity from any area of the scintillator ensures that images are obtained without shadow effects due to signal loss in the scintillator or due to detector geometry. The same probe current as for other detection modes can be used. Resolution of details is as high as for an SE image.
Direct observation of fracture in brittle materials in the SEM using a double torsion testing technique
Authors: Tait R. B. , Garrett G. G.
Published: August 2011

This paper describes an in‐situ testing technique for obtaining greater understanding of fracture mechanisms in brittle materials through direct observation of controlled fracture. The technique utilises constant stress intensity double torsion (DT) specimens loaded inside the specimen chamber of a conventional scanning electron microscope. With this method the control of discrete crack advance is extremely good, comparable with the limit of resolution. Evidence of the DT in‐situ method's fine control capability is illustrated by fracture observations in mortar, cement paste and tungsten carbide‐cobalt.
X‐ray image acquisition using an IBM‐PC
Authors: Lewis R. A. , Schick J. A.
Published: August 2011

The present interest among microscopists in digital image acquisition and analysis is surveyed and a trend towards using smaller computers identified. X‐ray images in particular are discussed. A simple arrangement for linking a Scanning Electron Microscope (SEM) based Energy Dispersive Spectroscopy (EDS) unit to an IBM Personal Computer (IBM‐PC) is described in detail. While readily available technical information is omitted, complete circuit diagrams and software flowcharts are given to facilitate reproduction of the system. Annotated listings of the programs used are available from the authors. Examples concerned with topographic effects in x‐ray maps illustrate the use of the system.
A three axis stereocomparator for scanning electron microscopic photogrammetry ‐ RS3
Authors: Howell P. G. T. , Boyde A. , Ross H. F.
Published: August 2011

Despite the topographic appearance of the image derived from the scanning electron microscope operated in the secondary electron emission mode it is impossible to make linear measurements from single two dimensional micrographs and relate these accurately to distances in the third dimension.

This paper describes a stereometer specifically designed for the examination and measurement of stereopair scanning electron micrographs. The new instrument uses rotary encoders attached to the movement of the photo‐carriage to register the coordinates of image features in both members of a stereoscopic. These raw data are passed to a microcomputer programmed for the reduction and conversion to real three dimensional values according to the geometry of the projection in scanning electron microscope image. This allows large quantities of data to be collated without the errors and tedium involved in manual collection.

The need for rapid data acquisition arose during a study on characterisation of resorption of bone by osteoclasts, where the collection and correlation of large quantities of data were required to permit a statistical interpretation to be made.
Elastic peak electron spectroscopy
Authors: Gergely G.
Published: August 2011

Elastic peak electron spectroscopy (EPES) determines the elastic peak intensity N (Ep) in absolute units (percentage). The experimental curve N (Ep) is affected by the type of electron spectrometer used (CMA, RFA, etc.) and represents the probability Pe (E, Z) of elastic electron reflection detected by the angular window of the spectrometer.

Pe (E, Z) = NAσeff (E, Z) Δ is the product of the inelastic mean free path Δ, the density NA of atoms and the effective elastic scattering cross‐section σeff (E, Z). Elementary processes of elastic scattering are treated with a simplified model based on a single scattering process. A more refined analysis will be to use the Monte‐Carlo approach. σeff is given by the differential elastic scattering cross‐section determined by the atomic number Z, the energy Ep, and the input and scattering angles. Results of σeff (E, Z) are presented based on tabulated differential cross‐section data published in the literature. Angular effects are discussed. A number of EPES applications are described for AES, plasmon‐, ionization‐, and low energy loss spectroscopies and SEM. EPES has been successful in the experimental determination of the inelastic mean free path Δ for a number of elements and compounds.
Efficient Detection of Secondary Electrons in Low‐Voltage Scanning Electron Microscopy
Authors: Zach J. , Rose H.
Published: August 2011

A new detection method is proposed allowing an efficient extraction of the secondary electrons without affecting the scanning spot of the primary beam. The suggested detector arrangements can be regarded as generalized Wien filters whose electric and magnetic fields do not affect the primary electrons with average beam energy, yet strongly influence the paths of the secondary electrons. The new detectors are especially useful in low‐voltage scanning electron microscopy.
Development of a scanning electron microscope with a two detector system
Authors: Drzazga W. , Grządziel I. , Kubera Cz. , Mokrauz I. , Słowko W. , Szymański H.
Published: August 2011

The authors consider the design feature of a prototype scanning electron microscope which they have constructed. The article serves as basic revision of the function of all the components in an SEM system, as well as illustrating the authors' choice of alternatives. A distinctive aspect of the present instrument is that the idea of incorporating two detector systems for SE was present from the beginning of the planning stages. The applicability of this system is illustrated by compositional (A + B) and topographic (A − B) SE images.
Digital image acquisition in scanning electron microscopy
Authors: Le Floch H. , Franceschi J.‐L. , Gouraud T. , Launay P.
Published: August 2011

Digital image acquisition is of great interest in SEM, as can be proven by the number of ways in which images can be improved by processing with this technique (Desai and Reimer 1985, Hawkes 1981).

In the case of the system described here, this interest is enlarged by the facility of storage and retrieval of images. In addition, a digital image becomes the only quantitative result when the “MEBIS” (Microscope Electronique à Balayage In Situ)is used as an automatic control tool whithin an industrial production line (Franceschi and Le Floch 1985).

This paper describes a system for acquisition, storage and processing of the images given by “MEBIS”, or other SEM if the scanning system includes a remote command. Software for preliminary processing for local representation is presented.

The main advantages of this system are its ease of use and its compactness; it is developed around the familiar and low‐cost Apple IIe microcomputer, presented in a portable version including a 5 video screen and a single disk drive in a ruggedized housing.
Rapid determination of the electron‐beam diameter
Authors: Hamerlik R.
Published: August 2011

In the present paper a method for the rapid determination of the electron‐beam diameter is described. The diameter is determined by means of the ratio of minimum and maximum signal in observing strip lines of known width, including the case that the width of strip lines is equal to the gap between them. The applicability of this method of measurement is limited only by the minimal dimensions of the strip lines achieved technologically. It is a suitable method first of all for the measurement of high intensity beams in VLSI circuit testing.
LASEM — a novel combined device for laser modification in SEM
Authors: Wetzig K. , Edelmann J. , Fischer W. , Mueller H.
Published: August 2011

An intense localized heat source inside a microscope could be useful in the improvement of electron microscopic in‐situ investigations. For this reason a JEOL scanning electron microscope was combined with a pulsed Nd‐glass laser which allowed power densities up to about 109 W/cm2 on the specimen under Q‐switch conditions. The mechanical and electrical adaptations necessary for the SEM‐to‐laser coupling, as well as some tests of the method involving the new equipment are discussed in detail in this paper. Various applications to materials are reviewed, including melting processes, thermal cracking and surface hardening of tungsten carbide alloys and other hard materials.
Segregation studies in low‐alloy steels by energy‐dispersive x‐ray spectrometry
Authors: Butler S. A.
Published: August 2011

An automated energy‐dispersive spectrometer/scanning electron microscope (EDS/SEM) system has been applied to the study of segregation in low‐alloy steels in which the base concentrations of the alloying elements are ⩽ 1.5 wt%. The distribution of elements within segregation bands is measured at several hundred points arranged on rectangular grids. By using suitable calibration standards, an accuracy for an individual analysis of about ± 0.05 wt% (one standard deviation) is obtained. By using statistical analysis of whole sets of data, the effects of large relative errors in individual values are minimized, and useful results are obtained even for concentrations much less than 1.0 wt%. It is shown that the maximum‐segregation ratio is unreliable as a measure of the severity of segregation, and is of limited use as an indicator of the likely effects on steel properties.
Characterization of polymer blends by low voltage scanning electron microscopy
Authors: Berry V. K.
Published: August 2011

A technique for characterization of polymer blends by low voltage scanning electron microscopy is described. The method allows observation of the distribution of phases in a blend due to good topographical and compositional contrast. This is possible because of lower beam penetration and high secondary emission coefficient (δ ⩾ 1) at low accelerating voltages. Uncoated polymer samples are imaged with no charging or beam damage problems. The technique has a great advantage over conventional transmission electron microscopy techniques because the sample preparation is minimal and larger areas can be prepared for viewing.
Scanning reflection image from a solid specimen in the scanning electron microscope with a condenser‐objective lens
Authors: Wells O. C.
Published: August 2011

To achieve the highest resolution in the scanning electron microscope (SEM) or in the scanning transmission electron microscope (STEM), the sample must be mounted in the high‐field region of a condenser‐objective lens. A secondary electron (SE) image can then be obtained using a collector before the lens. It is also possible to obtain a scanning reflection image by tilting the specimen so that the second half of the condenser‐objective lens field deflects the forward‐scattered electrons onto the transmission detector beyond the specimen. Experiments were made with an unmodified commercial SEM fitted with a condenser‐objective in the upper stage and with a transmission detector, and it was found that the scanning reflection image from a solid sample can provide additional useful information when used in conjunction with the SE image.
A computerized signal acquisition system for the quantitative evaluation of EBIC and CL data in a SEM
Authors: Bode M. , Jakubowicz A. , Habermeier H.‐U.
Published: August 2011

Electron beam‐induced current (EBIC) and cathodoluminescence (CL) are widely used methods to obtain information about recombination properties of semiconducting materials and their defects on a micrometer length scale. In this article a computerized SEM (scanning electron microscope) setup is described, which enables us to perform simultaneous measurements of several signals and automatic temperature‐dependent measurements. As examples for the performance of this system we present results obtained by simultaneous EBIC/CL experiments, allowing a reconstruction of the defect geometry. In a second example, the temperature dependence of the EBIC contrast is analyzed, introducing the method of EBIC spectroscopy.
Elemental imaging by electron energy loss microscopy
Authors: Ottensmeyer F. P. , Andrews D. W. , Arsenault A. L. , Heng Y. M. , Simon G. T. , Weatherly G. C.
Published: August 2011

Electron energy loss images obtained by parallel filtration at selected energies are used to derive qualitative and quantitative distributions of elements in specimens as diverse as low alloy steel, cartilage, and ribosomal particles. Partial ionization cross‐sections for electron scattering from phosphorus L‐shells are calculated.
Absorbed current: A source of information about voltage relations on measured specimen
Authors: Hamerlik R.
Published: August 2011

It is shown that a change in the SE current is opposite and equal in magnitude to a change in the absorbed current. Thus using the effect of potential contrast, allows measurement of voltage changes on a specimen by means of changes in the absorbed current. The present method offers a new possibility to complementary information, which can be helpful in various cases.
A PC‐AT‐based system for the acquisition of SEM images
Authors: Morandi C. , Vanzi M. , Bianco F. , Neri R.
Published: August 2011

A system for the acquisition of high‐quality DDVC (digital differential voltage contrast) images based on a low‐cost personal computer and a dedicated scanning electron microscope interface is described. It is capable of obtaining high‐quality voltage contrast maps of passivated integrated circuits even on supply lines, which are not usually seen due to static biasing. Grey‐level and colour image‐comparison utilities allow effective state‐by‐state comparison of a failed device with a good one, and are extremely useful for failure analyses.
A phase‐shift technique for high‐speed e‐beam testing with picosecond time resolution
Authors: Winkler D. , Schmitt R. , Brunner M. , Lischke B.
Published: August 2011

Electron beam sampling of high speed digital devices requires a high time resolution. At the same time, long‐range phase shifting is necessary because signals in these circuits may have very long period lengths. In this article, a new phase‐shift method is described which allows sampling of low repetition rate signals without any degradation of the time resolution. This long range phase shift is realized by an additional set of blanking plates or blanking capacitor, which, acting as a gate, selects one of a large number of electron pulses produced by a first blanking capacitor. This technique also allows fast switching between different phase angles. The phase‐shift method was evaluated experimentally using the picosecond e‐beam tester which was developed here. The time resolution of this tester has been optimized recently to allow for stroboscopic testing with a 7 ps pulse width at 20 mV/√Hz noise voltage and 0.5 μm spot size. This allows for the measuring of rise times down to 14 ps with an error below 10%. Phase shifts of 100 ns were realized without any degradation of this time resolution. Propagation delays of 3.5 ps could be resolved. Signal rise times of 40 ps, corresponding to 0.04% of the total delay could be easily measured.
Advantages of visualization of organelle structure by high resolution scanning electron microscopy
Authors: Hollenberg M. J. , Lea P. J.
Published: August 2011

Examination of subcellular structures in detail and in three dimensions (3D) by scanning electron microscopy (SEM) is now possible on a routine basis due to improvements in design of the modern scanning electron microscope and new methods of specimen preparation involving chemical removal of the cytosol and the cytoskeleton. Cells which have been fixed, frozen, cleaved, thawed, and subjected to cytosol removal exhibit constituents such as nuclear chromatin, cisternae of endoplasmic reticulum, mitochondria, and the Golgi complex in bold relief. This permits examination by SEM in 3D of these structures from several aspects at a resolution close to that of conventional transmission electron microscopy (TEM). As a result, minute changes in the 3D structure of subcellular components can now be easily and conveniently examined from many specimens and anatomical sites, in development, in a variety of physiological processes, and in disease. The SEM method offers many advantages over the various TEM techniques now used for similar purposes, since much larger areas of the specimen can be surveyed by SEM in a given time, sectioning is not required and minute 3D changes in nuclear and organelle structure can be identified and analyzed more easily. The advantages are such that a host of biological questions can now be answered by SEM which, so far, have resisted solution using only TEM techniques. In addition, a new field of pathological diagnosis using SEM may develop, using the advantages offered by the technique in exploring the cell's interior as well as cellular tissue organization.
Cathodoluminescence and transmission electron microscopy of an abrupt lateral junction in algaas grown by molecular beam epitaxy
Authors: Hoenk M. E. , Vahala K. J.
Published: August 2011

We present evidence for a novel type of junction, lateral to the growth direction, in AlGaAs grown by molecular beam epitaxy. Cathodoluminescence data show an abrupt change in the bandgap of AlGaAs grown in grooves on a GaAs substrate at the boundary between adjacent facets. Transmission electron microscopy of a cross section of the groove reveals an unexpected quasiperiodic compositional modulation on the (111) facets of the grooves. The transition in the bandgap occurs as a result of abrupt termination of the compositional modulation at the facet boundaries.
The use of a novel image‐shearing technique on a scanning electron microscope for comparative measurement of linewidths on photomasks
Authors: Nunn J. W. , Turner N. P.
Published: August 2011

A technique for measuring the widths of lines on chromium‐on‐glass photomasks is described which combines the resolution of the scanning electron microscope (SEM) with the accuracy of a helium‐neon laser interferometer, and the setting sensitivity of image‐shearing methods. Electron microscope image intensity profiles and the choice of signal which yields the best measurement repeatability are discussed. The technique described here yields measurements which are relatively insensitive to defocus and beam diameter.
Electron beam testing of circuits at liquid nitrogen temperature
Authors: Jenkins K. A. , Immediato M. J. , Heidel D. F.
Published: August 2011

An electron beam tester has been modified so that circuits being tested can be cooled to liquid nitrogen temperature. This enables voltage contrast imaging, and internal node probing, of low‐temperature circuits. Waveform measurements made in this way reveal details of low‐temperature circuit operation which cannot be easily obtained by any other means.
A modification of the ET secondary electron detector with a single crystal scintillator
Authors: Autrata R.
Published: August 2011

On the basis of the study of optical properties of single crystal YAG scintillators, it has been found that the maximum light output signal propagated in the required direction in the scintillator of a secondary electron detector is obtained if a cone‐shaped scintillator is used. A modified Everhart‐Thornley (ET) detector containing a conical scintillator and an electro‐optical diaphragm operated at a positive voltage shows an increase to 2.8 times the light output signal of the classical ET detector with a flat single crystal YAG scintillator disc. The modification allows optimization of the suction of secondary electrons toward the scintillator and of the propagation of light from the scintillator toward the light guide.
Scanning slit aperture confocal microscopy for three‐dimensional imaging
Authors: Burns D. H. , Hatangadi R. B. , Spelman F. A.
Published: August 2011

A scanning confocal microscope using stationary slit apertures of variable width is described. Scanning is achieved by employing an oscillating mirror galvanometer capable of scanning images at 160 frames/s. The microscope depth‐of‐focus is characterized for several slit widths and shown to approach diffraction‐limited performance as width decreases. Reduction of flare in images taken with narrow slit widths is demonstrated. In addition, the optical sectioning capability of the system is demonstrated using polymer casts of the vasculature of rat kidney.
Observation of the rabbit cornea and lens with a new real‐time confocal scanning optical microscope
Authors: Xiao G. Q. , Kino G. S. , Masters B. R.
Published: August 2011

A new one‐sided tandem scanning microscope (OTSM) has been utilized to optically section a transparent cornea and ocular lens with submicron depth and transverse resolution. Its high resolution, image quality, and contrast, together with color capability, real‐time operation, and easy alignment, have advantages over previous confocal systems. Planes within the nuclei of surface epithelial cells, the epithelial basement membrane, nerve fibers, the interior of endothelial cells, and the transverse structure of the lens fibers are readily observed. The utility of real‐time microscopic observation of live biological structures provides a new paradigm for cell biology and diagnostic ophthalmology.
Charging phenomena on insulating materials: Mechanisms and applications
Authors: Le Gressus C. , Valin F. , Gautier M. , Duraud J. P. , Cazaux J. , Okuzumi H.
Published: August 2011

We are interested in the physical origin of the electric charge that is produced in insulators by electron bombardment, by an electric field, or by mechanical stress. The charge is due to the trapping of carriers on the defects formed in the course of the dissipation of energy by the lattice. The characteristics of the charge (potential, electric field) result from the laws of electrostatics. The stability of the charge under an electron beam is interpreted on the basis of the laws governing the behavior of the discharges in gases and in solids. The stability of the charge after shutting off the beam depends on the position of the traps with respect to the surface and the experimental conditions (gas pressure, temperature, time). The charge decay kinetics are then controlled by adsorption‐diffusion. These studies allow us to explain some of the electromigration phenomena that had not been interpreted and to determine the optimal experimental conditions for the observation of local variations in the dielectric constant; they also allow the use of the charge phenomenon as an indicator of the mechanical and dielectric properties of insulators.
Comparison between the experimental and theoretical modeling of linewidth measurements on photomasks and their insensitivity to accelerating voltage in the scanning electron microscope
Authors: Nunn J. W.
Published: August 2011

A technique for measuring linewidths on chromium‐on‐glass photomasks in the SEM is described. The experimental observation that the width at the 50% intensity levels of the backscattered electron image intensity profile is largely insensitive to the accelerating voltage is backed up through Monte Carlo trajectory calculations. The theoretical model yields results which can be used to predict the position of the true edge from experimental intensity profiles to within 0.01 μm.
Sphincterlike structures in corrosion casts
Authors: Aharinejad S. , Franz P. , Böck P. , Lametschwandtner A. , Breiteneder H. , Firbas W.
Published: August 2011

Corrosion casts of the microvascular bed often show superficial constrictions, which may be interpreted as sphincters. In the present investigation, scanning electron microscopy (SEM) of vascular corrosion casts and transmission electron microscopy (TEM) of sectioned material were combined to obtain evidence on the wall structure in those regions where constrictions are seen. The study was performed on the microvasculature of the exocrine pancreas of rats and mice. Constrictions on casts of fenestrated or nonfenestrated capillaries correspond to cytoplasmic processes of pericytes. In the case of irregular superficial furrows and grooves on postcapillary veins and collecting venules the same situation is seen. Pericytes are not interpreted as sphincters. Deep constrictions were observed on casts of collecting venules in SEM, while in TEM they were shown to be caused by circular smooth muscle cells. The constrictions cause significant narrowing of the vascular lumen and are consequently interpreted as sphincters. Drastic narrowing of the capillary lumen was also seen where capillaries merge into postcapillary veins. TEM revealed the presence of pericytes in these regions. In our opinion, these narrowings functionally resemble sphincters, but there is no evidence for controlled closure and reopening as yet. Methodological conditions during tissue preparation, which may influence the appearance of casts in SEM, are discussed.
Cathodoluminescence of natural diamonds from Jakutian deposits
Authors: Zezin R. B. , Saparin G. V. , Smirnova E. P. , Obyden S. K. , Chukichev M. V.
Published: August 2011

We recount the study of plates cut from natural diamonds of mineralogical types I and IV with the use of optical polarization microscopy, photo‐ and cathodoluminescence (CL). A series of specimens exhibited two macroscopic zones of different structures characterized by the alternation of crystalline regions with different nitrogen contents. Diamonds are block structures with a lower nitrogen content. CL spectra were observed from central, intermediate, and peripheral zones of the plates. The crystal growth mechanism is discussed, and an attempt is made to correlate the spectroscopic measurements with the CL images formed in a color SEM. The findings may be useful in establishing a criterion to assess diamonds for certification.
Recent advances in scanning x‐ray microscopy
Authors: Morris D. , Buckley C. J. , Morrison G. R. , Michette A. G. , Anastasi P. A. F. , Browne M. T. , Burge R. E. , Charalambous P. S. , Foster G. F. , Palmer J. R. , Duke P. J.
Published: August 2011

A scanning x‐ray microscope has been built at the Daresbury synchrotron radiation source and used to obtain images at soft x‐ray wavelengths (∼2–4 nm). The focusing element of the microscope is a zone plate, fabricated by a contamination writing process developed at King's College. Zone plates with the finest zone widths, and hence theoretical resolutions, below 20 nm have been fabricated in this way. The contamination material is carbon, and as such is unsuitable for high‐efficiency focusing. In order to increase the zone plate efficiency, a shadowing pattern transfer process has been developed and used to replicate contamination lines with 25 nm widths into more suitable materials.
Measurement of microscopic displacements in graphite/epoxy composite materials using SEM‐generated fiducial markers
Authors: Burghardt R. C. , Ehrman J. M. , Stephens T. C. , Hibbs M. F. , Bradley W. L.
Published: August 2011

Graphite fiber‐reinforced resin composite materials are widely used in commercial applications where high strength and low weight are critical factors. In order to predict the fracture toughness of a composite material from the constitutive properties of the resin and fibers, experimental methods for the analysis of microscopic displacements and strain fields that develop at the fracture crack tip within the composite material are required. Information derived from measurement of displacements, and calculation of strain fields can then be used to test micromechanical models of matrix‐dominated fracture. A method was developed in which it is possible to conduct near real‐time fracture analysis of epoxy‐based composite materials, and to subsequently obtain micrometer‐scale measurements of displacements in the region of the crack tip. A map matrix was generated on the surface of test specimens in an SEM equipped with a tensile stage, along with an x‐ray spectroscopy and image analysis system. A 40 × 40 point digital map was introduced onto the surface of the specimen using the digital x‐ray mapping function of the x‐ray analysis system which produced a surface matrix with point spacing of 10 μm. The quality of maps varies with test specimens and therefore it is necessary to optimize microscope operation parameters for each resin tested. Reproducible results were obtained with both neat resins and graphite/epoxy composites. In situ analysis of a region of a propagating crack tip grown using the tensile stage reveals a deformation zone ahead of the crack tip and images of the stages of microcracking were captured by the image analyzer for subsequent measurement of displacement. Direct measurement of crack tip displacements from SEM electron beam‐induced reference matrices provide an important tool in characterizing the fracture behavior of both neat resin and composite materials.
Problems of low‐light detection in real‐time at high resolution
Authors: Gursky H. , Fritz G.
Published: August 2011

Various kinds of low‐light‐level detectors and image intensifiers are described and specific charge‐coupled device (CCD) developments are discussed from the perspective of the astronomical community, with possible application to optical microscopy. A number of research groups are reporting success at obtaining custom CCDs for application to high‐quality cameras working at low‐light levels. CCDs offer significant advantages in image quality and sensitivity compared with more traditional devices. Signal to noise (S/N) is derived for both CCDs and intensified devices. There is a tradeoff between the two and, because of the high read‐out rate required by microscopists, intensified devices still offer a S/N advantage at the lowest light levels.
The application and programming of an image store for the SEM
Authors: Hall M. G. , Hulbert J. K. , Zarucki P. N.
Published: August 2011

The programming and use of a purposebuilt digital image store constructed for a SEM is described. The system is based on purpose designed circuitry controlled by a Motorola MC68000 and is capable of noise‐averaging using multiple frames, colour look‐up tables, high‐resolution photographic recording, image processing using matrix functions, some image quantification, and x‐ray spectrum acquisition. The way in which the FORTH language provided an efficient means of controlling the SEM is described and examples of each type of operation are presented.
Signal strength and noise in confocal microscopy: Factors influencing selection of an optimum detector aperture
Authors: Sheppard C. J. R. , Cogswell C. J. , Gu M.
Published: August 2011

In confocal microscopy, several factors influence the selection of an optimum size and geometry of detector aperture. These include (1) strength of signal from the specimen, (2) noise level in the system, (3) optical configuration of the microscope (e.g., reflection or fluorescence), (4) time available for signal accumulation, (5) specimen thickness, and (6) amount of reduction in axial and transverse resolution (from the theoretical maximum) that can be tolerated. It is shown both theoretically and experimentally that the size of the detector aperture critically influences the type and amount of system noise that is detected along with the specimen signal. It is also demonstrated that increasing the size of the detector pinhole does not appreciably increase the signal strength from any single thin plane, but only increases the sampling depth, enhancing brightness at the cost of a reduction in axial resolution. As a result, it is shown that there is no advantage, from the standpoint of signal strength, to using a slit aperture rather than a circular detector pinhole. Finally, it is concluded that all confocal microscopes should be designed to allow the user the capability of selecting ah optimum compromise detector aperture setting based on the particular specimen properties, type of microscopy (e.g., fluorescence or reflection) and resolution required.
Complementary optical and electron microanalysis of high‐temperature superconductors
Authors: Hoff H. A. , Lechter W. L. , Toth L. E.
Published: August 2011

Scanning electron microscopy coupled to quantitative energy‐dispersive x‐ray spectroscopy provides an excellent tool for determining the compositions of various cuprate superconducting phases in the course of processing from insulator to superconductor. When coupled with a new room temperature optical microscopy technique for the identification of individual superconducting grains, it provides a complete picture of the processed state of the material. The techniques are complementary. Two different materials were examined with both optical and electron microscopy: (1) a Tl‐Sr‐Ca‐Cu‐O system superconducting material doped with Hg and (2) a metallic, but not superconducting La‐Sr‐Cu‐O system material. The results and the complementary nature of optical and electron microscopy in assessing the stoichiometry and homogeneity of these materials are described.
A routine correction for electron beam intensity variation during quantitative EDS microanalysis using continuum radiation
Authors: Griffin B. J. , Nockolds C. E.
Published: August 2011

A detailed investigation of the relationship between the mean atomic number and the intensity of high energy continuum radiation has verified earlier studies in defining a linear relationship. Corrections for matrix effects on the continuum intensity are found to be unnecessary within the precision limits of the data. Incorporation of this relationship into a quantitative energy‐dispersive spectrometer (EDS) microanalysis program allows internal correction for electron beam intensity variations between standard and unknown specimen analysis. It therefore allows quantitative analysis without normalisation on systems lacking any form of electron beam current measurement. Within limits, the need for reproducibility of electron beam intensity and counting time is eliminated.
Diagnostics of heterogeneous chemical reactions by cathodoluminescence
Authors: Melikhov I. V. , Saparin G. V. , Bozhevolnov V. E. , Obyden S. K. , Kuleshova O. V.
Published: August 2011

A scheme is developed for establishing the mechanism of heterogeneous chemical reactions by scanning electron microscopy (SEM) using cathodoluminescent markers (or flares CLF). Diagnostic formulas are found for the distribution function of product crystals with respect to their states under different reaction conditions. The diagnostic scheme is checked for the reaction of F‐apatite with phosphoric acid.
Calculation of depth distribution functions in films using an electron scattering model
Authors: August Hans‐Jürgen
Published: August 2011

An electron scattering model which has proved reliable in predicting both characteristic and continuous radiation depth distributions in bulk samples is further developed to cope with the quantification of depth distribution curves in thin films. The validity of the extended model is checked by comprehensive comparisons of calculated emitted x‐ray intensities with experimental data. The deviations obtained are generally small, the root‐mean‐square error being ∼5%. The results of calculations quantifying the effect of the substrate material on the shape of the depth distribution function in the film are also presented. The curves obtained are discussed in light of known theories and of fundamental physical considerations. The new model generates curves which correspond at least qualitatively with what is to be expected from basic principles and with the results of recent Monte Carlo simulations.
Cryopump vibration isolation system for an SEM
Authors: Postek M. T. , Keery W. J.
Published: August 2011

A standard commercially available cryopump system has been installed on a scanning electron microscope (SEM) using specially optimized vacuum vibration isolation bellows. This installation was successful in reducing the cryopump‐induced vibration to a level that did not degrade the standard performance or resolution of the SEM in the pump‐on mode and, in the pump‐off (or coasting) mode, eliminated all measurable instrument‐induced vibration (i.e., from the vacuum system). This article outlines the manner in which this performance has been accomplished and presents the results of an experiment demonstrating the reduction of specimen contamination provided by this type of vacuum system.
Nonoptical method of spectral cathode luminescence analysis
Authors: Kasparov K. N. , Zaretskii N. I.
Published: August 2011

A new method for measuring a monochromatic wavelength of cathodoluminescence using a scanning electron microscope is described. By eliminating losses of the optical system and ensuring a large relative aperture, it is possible to measure the wavelengths of luminous surface spots and compositions of spot sizes up to 2 μm; spectral resolution is about 3 nm.
Techniques for obtaining and observing complementary images with a low‐temperature field emission SEM and subsequent comparison of the identical cells in freeze‐etch replicas viewed with a TEM
Authors: Wergin William P. , Erbe Eric F.
Published: August 2011

Initial evidence shows that low‐temperature (LT) field emission scanning electron microscopy (FESEM) provides high‐resolution complementary images of frozen, fractured biological tissues and that the coating or replicas from the tissues can be recovered and viewed in the TEM to compare the identical cellular structures. To observe frozen specimens, a Hitachi S‐4000 FESEM was equipped with an Oxford CT 1500 Cryotrans System. The standard Oxford specimen carrier was modified to accommodate a Denton complementary freeze‐etch cap that would hold up to 6 hinged 24K gold specimen holders. This combination allowed observation of complementary images of sputter‐coated, freeze‐etched biological specimens at magnifications up to X30,000. Resolution of sputter‐coated images was also compared with that from evaporative coatings. Use of high‐vacuum evaporation of Pt/C in conjunction with LT‐FESEM provided useful resolutio up to X100,000. In addition, after these specimens were observed in the LT‐ FESEM, their coating, which consisted of a freeze‐etch replica, could be recovered from the frozen tissues and subsequently observed in the TEM at even higher resolutions. Consequently, complementary images of frozen, fractured, fully hydrated cells could be observed in the LT‐FESEM and then compared to the complementary images of the identical cells that were present in the replicas, which were recovered from the frozen specimens, and subsequently observed in the TEM. Being able to evaluate, compare, and contrast data from these two different EM imaging techniques as well as from complementary surfaces, not only provides additional information about the ultrastructure of a specimen, but also helps to assess the resolution of coating films, the presence of contaminants and the three‐dimensional distortion in replicas.
Ion microscopy imaging of various pyrimidic nucleotides and analogs in the nuclei of cultured tumor cells
Authors: Berry J. P. , Lespinats G. , Escaig F.
Published: August 2011

New applications for ion microscopy are presented. This method has been used primarily to detect mineral elements (K+, Na+, AL+). It also can be used to detect organic molecules containing halogen atoms and radioactive isotopes. 14C‐nucleotides and halogenated pyrimidic nucleotides and analogs were employed in this study. The various images obtained were correlated with the mechanism of action of these compounds, thus opening new lines of research.