William Keck Microanalysis Laboratory


The Microanalysis Laboratory, one of the eight well-equipped state-of-the-art laboratories of the Cerent Engineering Complex (Department of Engineering Science), consists of several major instruments at the present time. These include:

  • Hitachi Scanning Electron Microscope (SEM):
The SEM instrument is configured to allow imaging of inorganic objects as well as the more difficult to prepare and analyze biological specimens. Magnification up to 300,000X is well within the range of the instrument. A sample holder allows us to maintain the sample temperature from -20C to +85C. In addition, to the traditional SEM functionality, this instrument is equipped with Energy Dispersive X-ray Analysis (EDX). We are able to collect full atomic elemental analysis on a per pixel basis of the entire SEM image. As such we obtain extremely magnified images while simultaneously measuring the elemental content of any portion of the image.
  • Pacific Nanotechnology Scanning Probe Microscope (SPM):
    The Pacific Nanotechnology SPM is a tool that allows us to measure the properties of atomic surfaces. Sometimes the SPM is referred to as an Atomic Force Microscope (AFM). The SPM or AFM is comprised of a very small and sharp tip, the point of which is only a few atoms in diameters. This tip is connected to a cantilever and is moved in a systematic way over the surface of the sample. The repulsive Van der Waals force between the tip and the sample results in the movement of the cantilever. That movement is imaged via a secondary laser system built into the instrument. Typical scan areas can vary from 100 nanometers(nm) X 100 nanometers up to 100 microns X 100 microns. A nanometer is 10-9 meters, while a micron is 10-6 meters. The height profile ranges from 0.1 nm to 100 nm. An instrument similar to this instrument recently certified the average roughness of the mirrors used in the new NASA x-ray telescope EXAFS.
  • PHI Auger Spectrometer:
The PHI Auger spectrometer is an instrument that allows us to measure the strengths of various atomic bonds in a particular specimen. The EDX instrument mentioned above allows us to determine the presence of a particular atomic element in a specimen. The Auger spectrometer then allows us to probe the chemical nature of the specimen more deeply.

    [Please contact Dr. Hongtao Shi (hongtao.shi@sonoma.edu) if you are interested in learning more about the above instruments]

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  • Olympus Laser Scanning Confocal Imaging System:
The confocal imaging facility is equipped with an Olympus FV300 laser scanning system attached to an Olympus BX61 upright microscope. This system currently has three lasers: Argon (488 nm), Red HeNe (633 nm) and Green HeNe (543 nm) allowing the utilization of a wide range of fluorescent probes for specimen analysis. The unique feature of this instrument is its ability to generate 3D confocal images of a variety of living and non-living biological materials. With the help of an SIS Biological Suite Imaging Software, the digital camera attached to the above microscope system allows researchers to gather and analyze high quality bright-field, dark-field, phase and Nomarski-DIC images of specimens.

    [Please contact Dr. Murali Pillai (pillai@sonoma.edu) if you are interested in learning more about the above confocal imaging system]