SEM Imaging Laboratory

Imaging minerals and other geological, biological, and environmental materials at the micrometer scale.

 

Equipment: FESEM

Model/Brand: JSM-7800F JEOL

Specifications

Resolution:
  • 0.8 nm(15 kV)
  • 1.2 nm(1 kV)
  • 3.0 nm (15kV、5nA、WD10mm)
  • Magnification: ×25 to ×1,000,000(SEM)
  • Accelerating Voltage: 0.01kV to 30kV

  • Probe Current: Several pA to 200nA                                       

Specimen Stage: Fully eucentric goniometer stage

  • Low Vacuum Mode: Option to work at low vacuum (up to 300 Pa for uncoated, nonconductive samples)
  • EDS Detectors: 2 Oxford Xmax 150 mm2 detectors
  • EBSD Detector:  Oxford NordlysNano detector

 

Applications

Image and semiquantitatively measure the chemical compositions of minerals from all rock types. Map the compositional variations of minerals and rocks to observe zoning paterns, locate fine-grained phases, and determine relative proportions of phases (including vesicles). Characterise volcanic ash paricles based on morphology and constiuent minerals. Identify minerals using composition and crystal structure. Investigate morphologies of quartz sand grains to distinguish different sediment sources. Observe the morphology of microfossils such as foraminifera and diatoms. Measure the orientation of pheonocrysts in volcanic rocks. Differentiate calcite from aragonite in modern and ancient carbonates. Textural analysis of porphyroclasts in dynamically recrystallized rocks.

 

 

Equipment: High Vacuum Carbon Coating System

Model/Brand: Cressington 208carbon 9620-220

Specifications

  • Sample Table: Holds 12 SEM pin stubs; height adjustable through 60mm
  • Coating Material: Double-Tip Carbon Rods (2 step; Ø6.15mm)
  • Vacuum System: Pfeiffer turbo pump backed by a rotary pump allows for fast pumping down to 10-4 mbar

Applications

Coat a thin film of carbon on to the surface of nonconductive samples prior to imaging and analysis

 

 

Equipment: Sputter Coater

Model/Brand: EM ACE600 LEICA

Specifications

  • Different coating methods including sputtering, carbon thread, carbon rod and e-beam evaporation with the ability up use up to two methods at the same time in the same instrument
  • Angled sources attached to a metal vacuum chamber and a rotating stage to allow evenly distributed films on a stage size over 100mm

  • Pre-vacuum level, which is the main contributor to the granularity for a coated layer, can be set to the 10-6 mbar range (even less is possible) for high resolution imaging or to the  10-4 mbar range for quickly coating samples

Applications

Coat nonconductive samples with a very thin and homogenous film of metal (e.g., gold, platinmum) or carbon with nanometer-scale accuracy. The rotating stage allows for coating without shadows  to make smallest features visible.