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Research Technical Services

Scanning Electron Microscopy

(SEM)

Scanning electron microscopy (SEM) consists of tracing the surface of the sample with a focused electron beam. It provides high resolution and high depth of field images of the sample. It provides high resolution and high depth of field images of the sample. Associated with an X-ray detector by energy separation (energy dispersive x-ray spectoscopy EDS) it offers an identification of almost all the elements of the periodic table.

It is a very useful tool when the optical microscope does not provide the resolution the user needs.

We can offer personalised attention. The user is invited to accompany the technician in carrying out the study. This increases trust and ensures the confidentiality of the process.

Scanning Electron Microscope TESCAN CLARA

Job request

In order to request the analysis of a sample by MER, you must contact the staff responsible for the equipment, or by sending an e-mail to umb.str@udg.edu.

It is necessary to report the toxicity and the storage precautions and once the results have been delivered, if the sample is not picked up after a week, the rest of it will be destroyed.

The equipment

Scanning Electron Microscope TESCAN CLARA

Year:
2024
Resolution:

0.9 nm at 15 kV
Voltage of acceleration:
30kV
Useful increase:
x 1.000.000
Photographic register:
Digitised image of up to 16384 x 16384 pixels
Detectors:
· secondary electrons (SE)
· backscattered electrons (BSE)
· gaseous secondary electrons (GSE)
· scanning transmission electron microscopy
· energy dispersive X-ray (EDX)

Characteristics:
  • Bruker X Flash 7 energy dispersive X-ray microanalysis (EDX) system
  • Resolution: 129 eV (Mn Kα, 1000 cps)
  • Detector: Silicon drift droplet detector (SD3) with ultra-thin polymer window.
  • Detects elements with atomic number equal to or greater than 5 (B)
  • Low vacuum system up to 500 Pa
  • Refrigerated plates up to -50 ºC
  • Complementary devices for the preparation of samples
  • Associated computer equipment

How does it work?

  • The sample must withstand the vacuum inside the device.
  • The sample has to be conductive. Otherwise, it must be subjected to metal evaporation procedures to make it conductive.
  • The size of the sample must be compatible with the dimensions of the sample holder. We can introduce samples up to 8 cm2 and 1Kg in weight. Because of that, we sometimes need to cut it.
  • Obtaining the resolution we offer is often conditioned (limited) by the characteristics of the sample and its preparation.
  • Many of these limitations are solved with the suitable preparation of the sample. 

Advantages of the technique

  • Very good non-destructive qualitative analysis method of the analysed sample.
  • Rapid obtaining of the analysis (100 sec).

Limitations of the technique

  • The sample must withstand the vacuum inside the device.
  • Some materials are not stable in the electron beam.
  • Detection limit conditioned on the homogeneity of the sample.
  • If you want to do an EDX analysis and have to cover the sample with a Carbon vapour, to make it conductive, it can affect the quantification of the sample's own C.
  • Limited sensitivity for low atomic number elements.
  • Semi-quantitative analysis for samples that are not flat, polished or homogeneous.

Applications / Practical cases

  • Obtaining images with high resolution
  • Elemental microanalysis and particle characterisation
  • High depth of field. The entire image is in focus.

Scopes of application

  • Biology and Medicine: Ultrastructural studies of tissues and organs of living beings and their pathologies. Immunolocalisation
  • Geology: Mineralogical, crystallographic and petrological studies.
  • Characterisation of materials: Structural studies in materials like metals, polymers, semiconductors, ceramics, etc.
  • Metallurgy: Quality assurance. Studies of corrosion, fissures, deposits and fractures.
  • Restoration: Structural and chemical studies in works of art. Degradation and characterisation in monuments.
  • Control of quality and maintenances in industry: Studies in waters purification systems. Studies of surfaces: corrosion, fissures, deposits, etc. Evaluation and verification of the technical characteristics of the supplied and produced product.
  • Archaeology and Palaeontology: Archaeological tools. Forensic studies Study of archaeological teeth to determine their diet. Palaeobotany.
  • Expertises and forensic applications.

More information:

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