Scanning Electron Microscopy - Gbhenterprises.com

Materials Testing 

Scanning Electron 

Microscopy 

Test No.: M604 

Aim: Explanation of the basics of scanning electron microscopy using surfaces of fractures as an 

example. 

Comparison and analysis of differing fracture behaviour of metallic and polymeric materials 

by means of scanning electron microscopy. 

Contents 

1 Introduction 

1.1 Limitations of light-optical microscopy 

2 Basics 

2.1 Microscopy by employing electron beams 

2.2 Interaction between electrons and specimen 

2.2.1 Secondary electrons (SE) 

2.2.2 Back scattered electrons (BSE) 

2.3 Scanning electron microscope (SEM): Design and function 

2.3.1 Signal-producing system 

2.3.1.1 Generation of the probe 

2.3.1.2 Lens system 

2.3.1.3 Scanning system / magnification 

2.3.2 Signal-processing system 

2.3.3 Detectors 

2.4 Interrelationship between depth of focus, resolution, and magnification 

2.5 Fractographic analysis 

2.5.1 Transgranular and intercrystalline fracture 

3 Technological significance 

3.1 Assessment of damage 

3.2 Quality assurance and quality control 

3.3 Medical examination and biological investigation 

4 Testing 

5 Evaluation of testing 

6 Questions 

7 Bibliography

Test M604: Scanning electron microscopy 

1 Introduction 

Minor defects often result in considerable damage. Small fractures or cracks in materials can have 

disastrous effects on the stability of buildings, tools, etc. Once an accident has happened, its 

causes have to be found. A microscope examination of the fracture surface shows whether a 

material defect or a processing defect has caused the fracture. Light-optical and electron-optical 

microscopes are used for this purpose. Electron microscopes are advantageous in that a high 

degree of magnification as well as an excellent depth of focus (Fig.1) can be achieved. As a rule, 

surfaces of fracture are very rough so that a light-optical microscope often cannot produce a 

sufficiently clear enlargement of the relevant image section. 

Fig. 1: Photo of blood corpuscles taken by means of a) a light-optical microscope and b) an electron-optical 

microscope (same magnification). 

1.1 Limitations of light-optical microscopy 

The amount of information a micrograph can provide is dependent on resolution. The maximum 

resolution that can be achieved using a microscope means the smallest interval distinguishable 

between two adjacent points. Any magnification exceeding such maximum would not make sense 

since further information cannot be provided. 

The maximum resolution mainly depends on the wavelength of the radiation selected for the 

image. Beams entering the lens- and aperture system of the microscope produce overlapping 

diffraction patterns for each object point. The distance r 1 

between two diffraction maxima must 

exceed full width half maximum (FWHM), otherwise the diffraction maxima cannot be discerned 

as being separate (Fig. 2). According to a simple rule found by Rayleigh, distinction is possible 

when the maximum of the zero order coincides with the first minimum of the second diffraction 

pattern. The distance between the two first minima d 1 

is inversely proportional to the diameter of 

the aperture. 

2


Fig. 2: Minimal distance between two diffraction maxima still projected separately 

Diffraction patterns are dependent on the wavelength λ, on the index of refraction of the 

surrounding medium µ, and on the angle α formed by the optical axis and the edge beam, which 

can only just pass through the aperture. For r 1 

results: 

1 

0,61λ 

r 

1 

= d = 

(1) 

2 µ sinα 

The product µ sin α is referred to as numeric aperture. 

Thus, high resolution can be achieved by a short wavelength, a high index of refraction of the 

surrounding medium, and a short distance to the sample (hereinafter also referred to as 

"specimen") (wide angle α). When normal light-optical microscopes are used, the surrounding 

medium is air (µ = 1) and the distance between sample and lens cannot be decreased at discretion. 

For this reason, the maximum resolution with regard to wavelengths of visible light (400 - 700 

nm) is limited to about 200 nm, and any degree of magnification beyond 1000 would not make 

sense. 

2 Basics 

2.1 Microscopy by employing electron beams 

(Hereinafter the term "electron beam is also referred to as "probe"). If electrons are used instead 

of optical waves, much smaller wavelengths can be achieved. The wavelength can be varied 

depending on the voltage set to accelerate the electrons towards the sample. The velocity v of a 

single electron can almost reach the velocity of light c. In that case, relativistic corrections become 

necessary. The electron mass changes according to the following equation: 

me 

m = 

, ( 2 ) 

1 

2 2 

⎡ ⎛ v ⎞ ⎤ 

⎢1 

− ⎜ ⎟ ⎥ 

⎢⎣ 

⎝ c ⎠ ⎥⎦ 

m e 

is the rest mass of the electron. 

The deBroglie relation determines the interrelationship between wavelength and momentum. 

h h λ = = , ( 3 ) 

p mv 

h is Planck’s quantum (constant of action). The energy transmitted to an electron eV can be 

equated with the energy of relativistic mass changes: 

eV = m − m c 

(4) 

( ) 2 

e 

By means of these three equations the dependence of wavelength on accelerating voltage can be 

derived: 

3


2 

2 h 

λ = 

(5) 

2 2 

⎛ 2eVm 

+ ⎞ 

e 

e V 

⎜ 

⎟ 

2 

⎝ c ⎠ 

⎡ 1,5 ⎤ 

λ = ⎢ 

nm 

6 2 ⎥ 

(6) 

− 

⎣( V + 10 V ) ⎦ 

An accelerating voltage of e.g. 20 kV results in 8.6E-3 nm = 8.6 pm, whereas at 500 kV only 

1.4E-3 nm are reached. 

Since electrons would be too strongly scattered in air, a high vacuum is required in an electron 

microscope. In addition, the samples to be tested have to be electrically conductive, otherwise they 

would be overcharged with electrons during irradiation. For this reason, conductors and insulators 

of inferior quality have to be coated with a conductive layer of metal or carbon prior to 

microscopic investigation. 

2.2 Interaction between electrons and specimen 

Electrons in scanning electron microscopes are accelerated at voltages in the range of 2 to 40 kV. 

An electron beam < 0.01µm in diameter is focused on the specimen. These fast primary electrons 

(PE) interact in various ways with the surface layers of the specimen. The zone, in which such 

interaction occurs, and in which different signals are produced, is called "interaction volume" or 

"electron – diffusion cloud". The size of the interaction volume is proportional to the energy of 

primary electrons, its shape is determined dependent upon scattering processes by the mean atomic 

number. Secondary electrons (SE), back scattered electrons (BSE), and absorbed electrons are 

produced, flowing off as specimen current. In addition, X-rays, Auger electrons, and 

cathodoluminescence are produced (Fig. 3). 

1 

2 

Fig. 3: Interaction volume 

R: The range of primary electrons (PE); 

T: Escape level for back scattered electrons (BSE) 

Resolution limit of BSE ≈ ½ R 

Resolution limit of X-radiation ≈ interaction volume 

Resolution limit of secondary fluorescence > interaction volume 

4


2.2.1 Secondary electrons (SE) 

Although secondary electrons are produced in the entire interaction volume, they can only escape 

from surface layers (metals: max. 5mm, insulators: max. 50 mm, Fig. 4: Escape level t). 

Secondary electrons are very slow, their escape energy is ≤ 50 eV. Approximately half of all SE 

are produced very near to the point of impact of PE (SE1). Owing to back scattered electrons 

(BSE) diffusing in the specimen material, SE are also produced at a distance in the range of 0.1 to 

some µm to the point of impact (SE2). Back scattered electrons reacting with the wall of the 

specimen chamber are the third source of SE. This reaction process causes background radiation 

and thus a smaller degree of contrast, which, however, can partly be increased again electronically. 

(Fig. 4) 

Fig. 4: Production of SE and BSE 

The best lateral point resolution can be achieved by means of SE1. The signal can be intensified 

when the primary beam hits the samples at an angle of < 90°; this is referred to as inclination 

contrast. If radiation can penetrate specimen structures such as tips, fibres, or edges, the images of 

these structures will be very bright (edge contrast) owing to a high SE yield. 

The SE signal, comprising all essential information on topography, produces electron-micrographs 

of high resolution. 

Fig. 5: SE yield δ is dependent on the atomic number Z 

2.2.2 Back scattered electrons (BSE) 

The electrons escaping from the surface of the sample and having an energy of ≥ 50 eV are 

referred to as back scattered electrons (BSE). BSE are produced in the entire interaction volume at 

a larger distance to the point of impact of PE (Fig. 4). When atomic numbers are low, the escape 

5


level T is approx. half the range R; at accelerating voltages > 20kV and when atomic numbers are 

high, the escape level T is lower. The higher the PE energy and the smaller the atomic number of 

the specimen material, the more extends the area of production of BSE and the lower the 

achievable resolution. However, the dependence on the atomic number of the sample material is 

an advantage in that, apart from the topography contrast, a material contrast can be made visible. 

Moreover, owing to higher energy charging occurs less frequently than in case of SE. 

Fig. 6: RE yield η is dependent on the atomic number Z 

2.3 Scanning electron microscope (SEM): Design and function 

The surface of a specimen is brought into the focus of electron beams. The signals produced 

control the brightness of a screen tube such that an image of the surface of the sample appears. 

Fig. 7 illustrates the basic design of a scanning electron microscope. 

Fig. 7: Basic design of an SEM 

In a scanning electron microscope the signal-producing system and the signal-processing system 

operate independently. 

6


2.3.1 Signal-producing system 

The signal-producing system (see Fig. 7 to the left and Fig. 8) is to generate a probe of the 

smallest diameter possible and of maximum brightness when hitting the surface of the specimen. It 

consists of an electron gun, (cathode – Wehnelt cylinder – anode), lens system (lenses, apertures, 

beam deflection coils and stigmator coils) and the specimen chamber. 

Fig. 8: Course of the probe in the signal-producing system 

At least two pumps are required to reduce pressure to a vacuum. A vane-type rotary pump 

produces a pre-vacuum of approx. 10 -3 

mbar. Either a turbomolecular pump or an oil diffusion 

pump maintain the operation vacuum of at least 10 -5 

mbar in the column and in the chamber. 

Dependent upon the type of cathode used, a third pump, the ion getter pump, may be operated. 

For further information please refer to technical literature! 

2.3.1.1 Generation of the probe 

In the field of electron microscopy free electrons are usually produced by thermal emission. Other 

microscopes operate by means of field emission (> 10 9 V/m). Mostly, tungsten filaments or - as 

described here - LaB 6 

-crystals serve as cathode. The electron emitter consists of a three-electrode 

arrangement (Fig. 9). 

7


Fig. 9: Basic design of an electron gun. 

An electric heating current heats up the filament on the negative potential (cathode) opposite the 

anode. The relevant accelerating voltage accelerates the emitted electrons towards the anode where 

they pass through a gap to enter the microscope column. The filament is situated in a Wehnelt 

cylinder so that the electrons can be focused. The potential of the Wehnelt cylinder is slightly 

more negative than that of the filament. The Wehnelt cylinder focuses the electrons by emitting 

them from one point. This point, also referred to as virtual electron emitter or as cross-over, can be 

shifted by a variable bias resistance. The Wehnelt cylinder does not only adjust the diameter of the 

cross-over but the number of electrons leaving the cathode (emission current). 

2.3.1.2 Lens system 

Magnetic lenses and various apertures focus the electron beam. When an electron with the 

charge e and the velocity v reaches a magnetizing field of the intensity B, force F acts on the 

electron such that the force vector F is perpendicular to the velocity vector v and the magnetizing 

field vector B. 

F = e( B ∧ v) 

(7) 

Fig.10: Force vectors of a charge moving in the magnetizing field 

8


The magnetizing field of an electromagnetic lens can be divided into an axial and a radial part. 

The axial part, running in parallel to the direction of movement of the electron, does not influence 

the electron. The radial part, however, forces the electron to take a helix-path by the force 

(B rad 

e v). Thus, due to such circular component the velocity vector is influenced by the axial 

magnetizing field (B ax 

e v zirk 

). As a result the radius of the helix-path is becoming ever smaller. 

The electromagnetic lenses of an SEM produce an image reduced in diameter of the cross-over in 

the gun on the surface of the specimen. Two condenser lenses (Fig. 8) reduce the diameter of the 

electron beam (the diameter of the electron beam is also referred to as "probe size") from d 0 

to d 2 

. 

The higher the lens current, the smaller the diameter (Fig. 11). 

Fig. 11: Schematic illustration of the probe a) low, b) high lens current 

The smaller the probe size, the smaller the portion of electrons reaching the specimen since not all 

electrons leaving lens 1 can pass through lens 2. (Fig. 11): α 

2 

< α1 

. Increasing noise results, 

limiting the resolving power of the SEM. 

The third lens, i.e. the objective lens, focuses the probe towards the specimen. 

Lens holes which are not absolutely symmetrical mechanically, whose magnetizing fields are 

inhomogeneous, and whose pole piece holes are contaminated, and contaminated apertures in 

particular, will result in an elliptical probe producing "axial astigmatism". The surface of the 

specimen cannot be brought into focus accurately since an elliptical probe will produce a distorted 

image of specimen structures during the focusing process. A corrective magnetic field, required to 

recover the rotational symmetry of the probe, is to be produced by a stigmator. A stigmator 

consists of 2 times 4 coils arranged centrically towards the optical axis. 

2.3.1.3 Scanning system / magnification 

Beam deflection coils in a scanning generator (Fig. 7) scan the specimen surface by means of the 

primary electron beam for a certain period of time; beam deflection coils are installed in the pole 

piece duct of the objective lens. Simultaneously a cathode ray scans the screen of a monitor. 

Due to the principle of scanning, an SEM lineagraph consists of many spots. The beam deflection 

coil can be used to produce horizontal and vertical deflections by means of the electron beam. 

Horizontal deflection generates a line whose position is determined by vertical deflection. 

9


Scanning speed depends on the time set for the scanning of one line and on the number of lines per 

scanning process ("frame"). 

In order to increase magnification the current in the beam deflection coils must be increased. This 

involves a reduction of the scanning pattern produced on the specimen, whereas the size of the 

image displayed remains unchanged. Thus, magnification results from the ratio between the edge 

length of the screen and the edge length of the zone scanned on the specimen (Fig. 7). If, e.g., a 

zone of 1mm x 1mm is scanned, while the edge length of the screen is 30 cm, the degree of 

magnification will be 300-fold. 

2.3.2 Signal-processing system 

Fig.12: System of signal processing 

Due to the principle of scanning, signals - e.g. secondary electrons - are successively produced by 

each object point. After registration by means of a detector an electrical signal, the video signal, is 

generated and amplified by a preamplifier and by video amplification. The video signal, such 

amplified, modulates the cathode ray deflected simultaneously to the primary electron beam such 

that an image appears on the monitor. In this way, there is a spot-by-spot-correlation between the 

signal level of an object point and the brightness of the corresponding display spot. 

The amplitudes of the signal can be displayed as Y-modulation. 

The modulation of object signals to successive electrical signals is advantageous in that the latter 

can be modified in order to optimise image information (brightness, contrast etc.). 

2.3.3 Detectors 

Detectors connect the signal-producing and the signal-processing system of an SEM. They convert 

the signals produced (electrons) into electrical signals. As a rule, each signal (secondary electrons, 

back scattered electrons, X-rays) requires a special detector. 

10


Fig. 13: Everhart - Thornley – Detector 

K: Collector, S: Scintillator, LL: Optical fibre, V: Preamplifier, PM: Photo multiplier 

The most widely used detector of secondary electrons is the Everhart-Thornley-Detector (Fig. 13). 

A driving potential of e.g. +300 to 400 V is applied between the specimen and the collector for the 

intake of secondary electrons of low energy. Between collector and scintillator, high voltage of 10 

kV is applied, accelerating the SE to come forcibly into contact with the scintillator. The 

scintillator consists either of a glass plate coated with luminescent powder (phosphor compound) 

or of a YAG- or YAP- monocrystal. The photons produced pass via the optical fibre to the photo 

multiplier. The photons release electrons at the photocathode of the multiplier. The multiplier 

voltage accelerates these electrons towards the dynodes where they produce cumulatively a 

multiple of electrons. 

BSE are also detected. If an image is to be produced by BSE only, no SE must be present; the 

collector must be switched off or a negative voltage must be applied to repulse the SE. 

Scintillator detectors (Robinson detector) or semiconductor detectors are especially in use to detect 

BSE. 

2.4 Interrelationship between depth of focus, resolution, and magnification 

Great depth of focus is required for an analysis of fracture surfaces. The term "depth of focus" 

describes that zone of object positions, in which a change in focus cannot be perceived through the 

sight. Fig. 14 shows the interrelationship between the depth of focus and the point resolution X or 

magnification. 

At a 1000-fold magnification, the light-optical microscope can only project a depth of approx. 

0.2 µm, whereas 100 µm can be achieved by means of an electron microscope. 

11


Fig. 14: Interrelationship between depth of focus, point resolution, and magnification: Light-optical microscope 

and scanning electron microscope. 

2.5 Fractographic analysis 

Any fracture of a body starts with the formation and propagation of cracks in submicroscopic, 

microscopic, and eventually macroscopic dimensions. The structure of the fracture surface varies 

depending on the composition and microstructure of the material in question as well as on other 

conditions given during the process of breaking, such as temperature and stress state. Thus an 

analysis of the fracture surface can provide essential information on the cause of fracture. 

2.5.1 Transgranular and intercrystalline fracture 

Metals are composed of a multitude of small crystallites formed when the melt is cooling down. 

Atoms are very regularly arranged in the crystallites. At the boundary between two crystallites the 

order of the crystal lattice is disarranged. These crystal boundaries show two-dimensional lattice 

defects. As the atoms at the crystal boundaries are not in an equilibrium state, the crystal 

boundaries in engineering materials are in general of higher strength than those of regular 

crystallites. They form a barrier to the propagation of small cracks so that - at room temperature 

and at lower temperatures - cracks normally run through the grains. This process is referred to as 

transgranular fracture (Figs. 15 a and c). 

12


Fig. 15: a) Transgranular cleavage fracture, b) intercrystalline cleavage fracture c) dimple fracture 

(transgranular), d) fatigue fracture 

Various types of separation occur in brittle and tough material. In the case of transgranular brittle 

fracture, crystallites are split without deformation (Fig. 15a). If the material is tough, sliding 

processes occur in crystallographically preferred planes; microvoids and cavities form themselves. 

The cavities widen, any metal remaining in between propagates and narrow edges are formed. The 

resulting microstructure is called dimple fracture, see Fig.15c). 

Cyclic straining (cf. Test M512) leads to transgranular cracks showing fracture paths and fatigue 

striation (Fig. 15d). 

At higher temperatures atoms move more easily, and the strength of crystal boundaries is reduced. 

The path of fractures that have occurred after a long time of load at high temperatures runs along 

crystal boundaries. Such fractures are referred to as intercrystalline fractures (Fig. 15b); they do 

not occur at room temperature unless crystal boundaries have been weakened or embrittled due to 

precipitation or impurities. In particular the influence of hydrogen can also lead to intercrystalline 

fractures. 

3 Technological significance 

3.1 Assessment of damage 

As has been mentioned in the introduction, scanning electron microscopy is essential to an 

assessment of causes of damage due to fracture. Microscopic analysis has made it possible to 

distinguish between material defects and processing defects. Thus, considerable legal 

consequences may result with regard to liability for damage. 

Slag inclusion in welding seams, e.g., cannot be clearly identified using a light-optical microscope 

whereas, owing to the fact that the conductivity of metal differs considerably from that of slag, 

13


contrasts become clearly visible when an electron microscope is used. In connection with X-ray 

analysis, such slag inclusion can be clearly identified. 

Heavy expenses occur to insurance companies, both in the commercial and in the private field, for 

the evaluation of damage due to corrosion of water pipes etc. The cause of corrosion can be 

determined by electron-microscopic investigation such that e.g. defective connections between 

different metals can be located. 

3.2 Quality assurance and quality control 

Electron microscopes are well suitable for controlling and ensuring e.g. a constant surface quality 

or a defined roughness of workpieces. However, some disadvantages must be mentioned here, too. 

In practice, electron microscopes cannot be integrated directly in a production line as they require 

high-vacuum for operation so that usually investigation can only be made by taking samples. 

Apart from vacuum resistance, the electric conductivity of the specimen surface is of utmost 

importance. Although electric conductivity is easy to achieve by coating even relatively sensitive 

organic material with metal or carbon, there are high expenses involved so that a wide application 

of this method would be disadvantageous. Meanwhile the development of atomic force 

microscopy has become a competitive alternative as far as topographic investigation is concerned: 

The forces of attraction acting between the specimen surface and the measuring prod are 

determined in atomic dimensions. 

3.3 Medical examination and biological investigation 

Particularly in the field of medical and biologic research, electron microscopy has enormously 

contributed to improve examination and investigation. Here, low-vacuum units have been 

developed, enabling the investigation of non-conducting, hydrous, organic preparations. The great 

depth of focus is not as important as the fact that the 1000-fold magnification achieved by an 

optical microscope can be exceeded. 

4 Testing 

In the course of this test you are to analyse and compare the differing fracture behaviour of 

metallic and polymeric materials in order to give an example of scanning electron microscopy as 

frequently used in practice. Use the surfaces of fracture obtained as a result of other tests 

conducted in this laboratory course, e.g. the tensile test or the notched-bar impact test. As far as 

metals are concerned use the samples cut to adequate size (no further preparation necessary). In 

case of polymeric materials, insulators are usually used. Prior to testing, coat the specimen 

surfaces with a thin film of precious metal to prevent charging. For this purpose a low-vacuum 

cathode sputtering unit is available 

Do not operate the electron microscope and the cathode sputtering unit unless the adviser is 

present. Follow the instructions to the letter! 

For purposes of documentation and later evaluation store and print typical images of the specimen 

you have tested. 

Carefully note down in writing information obtained and experience gained during the laboratory 

course! 

Specimen 

The adviser will hand over the specimen to you. 

Testing equipment 

Scanning electron microscope SEM XL30 (Philips) 

Cathode sputtering unit SCD 050 (Baltec) 

14


5 Evaluation of testing 

Prior to giving your results, describe in detail the theory of the electron microscope. Describe 

experience gained and information obtained from the specimen, referring to theory. If necessary, 

consult technical literature. 

Describe the individual fracture behaviour of each specimen. Determine - to the extent possible - 

the average dimensions of characteristic features such as size of crystallite, size of dimple, fatigue 

striation. Briefly describe the differing material properties or conditions of fracture, respectively, 

that have caused the surfaces of fracture you observed. 

6 Questions 

• How can the range of usage of a light-optical microscope be extended 

• Which are the advantages/ disadvantages of transmission electron microscopy (TEM) in 

comparison to scanning electron microscopy (SEM) 

• Which are the scattering types that can occur at atoms in case of accelerated electrons Give 

some examples! 

• Field emission SEM: Describe the principle! Which are the advantages of this method 

7 Bibliography 

• Macherauch, Eckard: Praktikum in Werkstoffkunde (Laboratory course in 

metallography); Publishing house: F. Vieweg & Sohn, 

Braunschweig / Wiesbaden 1992 

• Flegler, Heckman, Klomparens: Elektronenmikroskopie (Electron microscopy); 

Publishing house: Spektrum Akademischer Verlag, 

Heidelberg 1995 

• L. Reimer, G. Pfefferkorn: Rasterelektronenmikroskopie (Scanning electron 

microscopy); Publishing house: Springer-Verlag, 

Berlin 1977 

• L. Engel, H. Klingele: Rasterelektronenmikroskopische Untersuchungen von 

Metallschäden (Scanning electron microscopy used for 

the inspection of damage to metal), Publishing house: 

Gerling, Köln 1982 

• W. Schatt.: Einführung in die Werkstoffwissenschaft (Introduction to 

materials science), Publishing house: Deutscher Verlag 

für Grundstoffindustrie, Leipzig 1972 

• E. Hornbogen, B. Skrotzki Werkstoffmikroskopie (Materials microscopy), 

Publishing house: Springer Verlag, Berlin 1993 

15


Abbildungen des Versuchs M604 

Abb. 3 

Primärelektronenstrahl 

primary electron beam 

1 mm Auger Elektronen Auger electrons, 1 mm 

Rückstreuelektronen 

back scattered electrons 

Charakterische Röntgenstrahlung 

characteristic X-radiation 

Röntgenstrahlung: Kontinuum 

X-radiation: continuum 

Sekundäre Fluoreszenz (Kontinuum und 

charakteristische Röntgenstrahlung) 

Secondary fluorescence (continuum and 

characteristic X-radiation) 

RE-Auflösung 

BSE resolution 

Röntgenstrahlung, Auflösung 

X-radiation, resolution 

Abb. 4 

Wandung 

wall 

zum Detektor 

towards detector 

Probenoberfläche 

specimen surface 

Austrittstiefe 

escape level 

Reichweite 

range 

Elektronendiffusionswolke 

electron diffusion cloud 

Abb. 5 

Ordnungszahl 

atomic number 

Abb. 7 

Elektronenstrahl 

electron beam 

Kondensorlinsen 

condenser lenses 

Ablenkspulen 

beam deflection coils 

Objektivlinse 

objective lens 

Probe 

specimen 

Verstärker 

amplifier 

Rastereinheit 

scanning unit 

Signaldetektor 

signal detector 

Sichtbildschirm 

screen 

Abb. 8 

Kathode 

cathode 

Wehneltzylinder 

Wehnelt cylinder 

Anode 

anode 

Sprayblende 

dispersion aperture 

Kondensorlinse 

condenser lens 

Stigmator 

stigmator 

Objektiv 

objective 

Bildfeinverschiebung 

fine-adjustment of micrograph 

Aperturblende 

aperture diaphragm 

Probe 

specimen 

Abb. 9 

Elektronenkanone 

electron gun 

Hochspannungskabel 

high-voltage cable 

Keramikisolator 

ceramic insulator 

Wolframdrahtfaden 

tungsten filament 

16


Vakuumdichtung 

Abschirmung oder Wehneltzylinder 

Anode 

Abb. 11 

Linse 

Abb. 12 

Elektronen-optische Parameter 

Vorverstärker 

Videoverstärker 

Kontrast 

Helligkeit 

Differenzierung 

Inversion 

Oszillograph 

weiß 

schwarz 

Photobildschirm 

Beobachtungsbildschirm 

Abb. 14 

Punktauflösung 

Schärfentiefe 

REM 

Förderliche Vergrößerung 

Betr. Querverweis auf M512 

transkristallin 

(in M512 engl. "transcrystalline") 

interkristallin 

Bruchbahnen 

(in M512 eng. "slip planes") 

Schwingungsstreifen 

(in M512 engl. "nodal lines") 

vacuum seal 

shielding or Wehnelt cylinder 

anode 

lens 

electron-optical parameters 

preamplifier 

video amplification 

contrast 

brightness 

differentiation 

inversion 

oscillograph 

white 

black 

screen / micrographs 

screen 

point resolution 

depth of focus 

SEM 

useful magnification 

M604 

transgranular 

intercrystalline 

fracture paths 

fatigue striation 

17

Scanning Electron Microscopy - Gbhenterprises.com

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?