EDX background - MAT E 211 EDX Operation J.B. Wiskel/C....

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MAT E 211 EDX Operation J.B. Wiskel/C. Barker EDX Procedure (point or area analysis) 1. In order for fully quantitative analysis to be performed, the sample must be flat and polished as the TOA (take-off angle) for the X-rays must be a constant. Therefore, the sample must be polished down to the final stage (usually 0.5 micron alumina). 2. If the sample is mounted in a non-conductive material such as epoxy, bakelite, or lucite, then carbon must first be evaporated onto the sample surface. It then must be grounded to the sample holder with either conductive tape (copper or carbon) on a fast drying liquid known as colloidal graphite. 3. Screw the sample holder onto the end of the specimen exchange rod and evacuate the airlock on the Scanning Electron Microscope (SEM). Wait for the green (vacuum ready) light. Open the valve to the main chamber of the SEM and slide the sample holder into the jig in the SEM chamber. Close the valve to the main chamber & wait for the green ready light on the top left of the main SEM console to stop flashing (indicates that a vacuum of at least 10 -5 torr has been achieved). 4. Turn on the accelerating voltage. Press the fast waveform monitor button on the SEM console. Turn up the filament current and stop just at the point where it reaches a maximum. This is known as saturating the filament and is the point at which the current is the most stable and the filament has the longest life. 5. For both EDX and Backscattered Electron (BSE) imaging, the optimum working distance (WD) is 17mm. Therefore, the specimen height must be adjusted with the Z control and the image focused until a WD of 17mm is achieved. The WD value is displayed on the SEM monitor. 6. If the sample contains different phases, then the Backscattered Electron (BSE) detector may be used in addition to (or instead of) the Secondary Electron (SE) detector, which is a fixed position detector used for imaging topography. Ensuring that the working distance is 17mm, move the BSE detector into position over the sample and adjust the brightness and contrast on the separate vertical control panel located beside the
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This note was uploaded on 04/27/2010 for the course MAT E 211 taught by Professor Wiskel during the Winter '10 term at University of Alberta.

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EDX background - MAT E 211 EDX Operation J.B. Wiskel/C....

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