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CCMR - RET 2008 WEEK 5. A type of electron microscope that images the sample surface by scanning it with a high-energy beam of electrons in a raster scan pattern. . SEM (scanning electron microscope). How does SEM work?.

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Sem scanning electron microscope

A type of electron microscope that images the sample surface by scanning it with a high-energy beam of electrons in a raster scan pattern.

SEM (scanning electron microscope)


How does sem work
How does SEM work? by scanning it with a high-energy beam of electrons in a raster scan pattern.

  • Electron beam interacts with the material, causing a variety of signals to be emitted-revealing details of the material’s shape, homogeneity and elemental composition.


Sem images
SEM Images by scanning it with a high-energy beam of electrons in a raster scan pattern.

  • Low accelerating voltages

    • finer surface structure images can generally be obtained.


Sem images1
SEM Images by scanning it with a high-energy beam of electrons in a raster scan pattern.

  • High accelerating voltages

    • the beam penetration and diffusion area become larger, resulting in unnecessary signals being generated from within the specimen.


Sem images2
SEM Images by scanning it with a high-energy beam of electrons in a raster scan pattern.

Lichen

Unknown


Electron microprobe

Electron Microprobe by scanning it with a high-energy beam of electrons in a raster scan pattern.

1149 Snee Hall


C. by scanning it with a high-energy beam of electrons in a raster scan pattern. The electrons hit the sample

- This knocks out inner electrons in the sample

- The atom is now in an excited state. An outer electron drops down to the inner energy level releasing energy in the form of x-rays at the same time.

A.Electrons are generated by heating a tungsten filament similar to the one in a light bulb.

B.Electrons pass through lenses that condense the beam, remove aberrations and focus the beam

E.The reflected rays are then counted and recorded by a detector.

D.X-rays are then reflected through a crystal

probelab.geo.umn.edu/electron_microprobe.html


Electron microprobe uses
Electron Microprobe Uses by scanning it with a high-energy beam of electrons in a raster scan pattern.

  • Non - destructive

  • Compositional Analysis

    • Quantitative

    • Qualitative

  • Precise X-Ray intensities

  • High Spectral Resolution

http://www.authorstream.com/Presentation/Janelle-19809-Electron-Beam-MicroAnalysis-Geol-619-1-History-Electrons-as-Entertainment-ppt-powerpoint/


Applications of the by scanning it with a high-energy beam of electrons in a raster scan pattern.

Electron Microprobe


Case Study One – What is under the fingernails? by scanning it with a high-energy beam of electrons in a raster scan pattern.

Clay?


Paint? by scanning it with a high-energy beam of electrons in a raster scan pattern.


Lichen? by scanning it with a high-energy beam of electrons in a raster scan pattern.

SEM image


Insect Wing? by scanning it with a high-energy beam of electrons in a raster scan pattern.

SEM image


Electron Microprobe Analysis by scanning it with a high-energy beam of electrons in a raster scan pattern.

Since the fingernail is an organic compound, there was a

large carbon peak. Other elements such as calcium and sulfur

might be found in fingernails normally.


Other Applications of Electron Microprobe by scanning it with a high-energy beam of electrons in a raster scan pattern.


GEOLOGY- by scanning it with a high-energy beam of electrons in a raster scan pattern.

Chemical analysis of rocks, dating, plate tectonics


Archeology by scanning it with a high-energy beam of electrons in a raster scan pattern.

Compositional distinctions between 16th century ‘fac¸on-de-Venise’ and

Venetian glass vessels excavated in Antwerp, Belgium†

I. De Raedt,aK. Janssens*a and J. Veeckmanb

aDepartment of Chemistry, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp, Belgium.

E-mail: [email protected]

bExcavation Department of the City of Antwerp, Godefriduskaai 36, B-2000 Antwerp, Belgium

Received 29th October 1998, Accepted 10th December 1998

At

JEOL 6300 SEM/EDX

Based on chemical analysis,

50% of the glassware was from Italy


FORENSIC SCIENCE by scanning it with a high-energy beam of electrons in a raster scan pattern.

  • SEMGSR

    The SEM solution for Automated

    Analysis and Classification of

    Gunshot Residue

SEM/ Microprobe is used to analyze

inorganic compounds in gunshot residue


STUDY POTENTIAL ELECTROCATALYSTS by scanning it with a high-energy beam of electrons in a raster scan pattern.

FOR FUEL CELLS

(Based on lecture by Hector Abruna)

Sputter different concentrations

of metals onto a substrate


2. Perform Thermal imaging to determine areas of by scanning it with a high-energy beam of electrons in a raster scan pattern.

higher electrochemical activity

3. Use scanning electrochemical microscopy (SECM)

to test sample’s ability to oxidize hydrogen/formic acid

and reduce oxygen.


Now we need to determine the chemical composition by scanning it with a high-energy beam of electrons in a raster scan pattern.

Of the product before bulk manufacture

Obtain composition with microprobe

and Rutherford backscattering (RBS)

SEM-Observe texture and crystal grain size

GADDS-Determine crystal structure


Niobium/Tin Film Studies by scanning it with a high-energy beam of electrons in a raster scan pattern.


Unannealed by scanning it with a high-energy beam of electrons in a raster scan pattern. Sample- 2 to 1 Niobium to Tin


Annealed Sample - by scanning it with a high-energy beam of electrons in a raster scan pattern.

Large peak seen for Niobium.

About 10% of mass unaccounted for.

Oxygen accounted

the missing mass- the niobium was probably oxidized.


Butterfly wings

Butterfly Wings by scanning it with a high-energy beam of electrons in a raster scan pattern.

-The Sequel-


Light microscope images
Light Microscope Images by scanning it with a high-energy beam of electrons in a raster scan pattern.

20µ

Butterfly Scales showing overlapping pattern

10µ

Individual scales showing ribbing pattern


Light microscope views
Light Microscope views by scanning it with a high-energy beam of electrons in a raster scan pattern.

20 µ

10 µ

Fringe Scales

Tips of Fringe scales


Fringe scales of wing
Fringe Scales of Wing by scanning it with a high-energy beam of electrons in a raster scan pattern.

100 µ

50µ

Optical Microscope -Transmitted Light

Optical Microscope – Reflected Light


Unpolarized vs polarized light
Unpolarized vs Polarized Light by scanning it with a high-energy beam of electrons in a raster scan pattern.

10 µ

10µ

Wing Scale Unpolarized Light 50x objective lens

Wing Scale Polarized Light 50x objective lens


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