Geology Scholarship Proposal - Example
Introduction: The Scanning Electron Microscope (SEM) is designed to examine and image objects at magnifications of up to 300,000X. It uses a filament that sends a beam of electrons towards the sample. The beam travels through two sets of lenses before reaching the sample, where it is usually rastered in rows. Electrons bouncing back from the surface of the sample are then used to generate a 3D like image. The incident electrons can also generate X-rays characteristic of the elements contained in the sample examined. Collection of these X-rays by an energy dispersive spectrometer (EDS) yields information on the elemental composition of the sample (Goldstein et al., 1981; Reed, 1996). However, all of the data collected with the EDS is qualitative.
Significance: The objectives of this project are: (i) to calibrate the SEM and EDS detector for the elements: Si, Al, Fe, Mg, Ca, Na, K, Ti, P, Cr, Mn, Zn, and Cl using a set of well characterized standards, so that it can be used in the future for analysis of minerals, (ii) to test the precision and accuracy of the calibration using other standards and previously analyzed (and well characterized) minerals; and (iii) to write a protocol for the routine calibration and quantitative analysis of minerals, metals, and alloys.
Experimental Approach and Work Plan: The department of Chemistry will offer the 4 credit hour class CHM483 “Advanced Microscopic Techniques” next Spring which I plan on taking. This will familiarize me with the procedures of operating the SEM. In addition, I will be working on the calibration of the electron beam and EDS detector for ~ sixty five hours; averaging four - five hours a week. Calibration will be done using a set of well characterized mineral and oxide standards provided from the Smithsonian Institute that are pure and homogenous. These standards have been mounted on a block that can also hold a standard thin section of a rock or mineral. This design would allow for the analysis of unknowns immediately after standardization. Beam calibration and standardization will be carried out using the LINK ISIS 300 software (v. 3.02) available in the lab and following the procedures outlined in the manuals provided by Oxford Instruments. I will then test the accuracy of my standardization by analyzing multielement Smithsonian standards (not used in the original standardization) and minerals of known composition provided by the Geology faculty. Precision will be gauged by the ability to replicate our results.
Outcomes: Calibration and standardization of the electron beam and EDS will
allow for the quantitative analysis of minerals in thin sections. I plan on
analyzing coexisting minerals from schists and
Essene, E. J., 1982. Geologic thermometry and barometry. In Ferry, J. M.(ed.) Characterization of metamorphism through mineral equilibria. Reviews in Mineralogy, 1): 153 – 206.
Goldstein, Joseph I.; Newbury, Dale E.; Echlin, Patrick;
Joy, David C.; Fiori, Charles; Lifshin,
Eric, 1981. Scanning Electron Microscopy and X-Ray Microanalysis: A Test for
Biologists, materials Scientists, and Geologists.
Reed, S.J.B., 1996. Electron Microprobe Analysis and Scanning Electron Microscopy in
• Student stipend: $1000
• All the supplies will be provided by the department of Geology at Marshall University.