Scanning Electron Microscope
Scanning Electron Microscope (SEM) is an important tool for imaging material surface as well as for identifying chemical signatures. The UF Geology department recently established a SEM laboratory equipped with EVO MA10 XVP which is one of the most upgraded models in the Carl Zeiss’ EVO series (as of 2008). Among various features of this model, followings are considered to be directly beneficial to a wide range of users: (1) it can dynamically image partially wet, hydrated samples, (2) VPSE detector can generate sharp cathodoluminescence images, (3) analytical working distance can be variable from 2.0 to 20 mm without compromising any other functionality, (4) 5-axis motorized stage can be fully tilted for imaging large samples with very uneven surface. Detailed description of this model is available at the manufacturer’s website.
- The present SEM system is equipped with following detectors for diverse applications:
- Secondary Electron Detector (SED)
- Variable Pressure Secondary Electron Detector (VPSED)
- Backscattered Electron Detector (BSD)
- Energy Dispersive X-ray Spectrometer (EDS or EDX: “GENESIS XM2” manufactured by EDAX)
- Cathodoluminescence detector (CLD: “MiniCL” manufactured by Gatan)
Targets and Sample Preparation
The targets can be almost any type of solid materials having resistance to incident electron beam (<30 kV). Common examples are metal, rock, soil, glass, plastic, polymer, fiber, ceramic, concrete, biological entities, or any combination of these.
The MA10 introduces controlled pressure of water and air to the chamber. Interacted with secondary electrons, the introduced water molecules become ionized, efficiently neutralizing charges (electrons) accumulating on the sample surface. Because of this capability, the MA10 can generate a stable signal for non-conductive specimens, eliminating the need of coating those with conductive substances. This capability allows for users to perform SE/CL imaging and EDS analysis with least chemical contamination of the target – this aspect is important for some applications which require multiple experiments on a single specimen with minimal interference. If coating is desirable for your applications, the Denton Sputter Coater (Desk IV) with carbon evaporation accessory is available in the lab.
If there is enough demand, the current SEM system will be upgraded by adding water kit (coolstage and vapor introduction kit) in order to improve the capability of analyzing fully wet samples (max chamber pressure=750 Pa). We also plan to install Wave Dispersive X-ray Spectrometer (WDS) for more quantitative, in-situ elemental analysis.
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*Assistance is required at the beginning stage of sample analysis for any new users.
Please contact Dr. Heatherington to schedule your analyses.