Scanning Electron Microscopy: Difference between revisions
Jump to navigation
Jump to search
No edit summary |
No edit summary |
||
| Line 10: | Line 10: | ||
|'''Detectors''': Secondary (SED) & Backscatter (BSD) | |'''Detectors''': Secondary (SED) & Backscatter (BSD) | ||
|- | |- | ||
|'''Capabilities''': | |'''Capabilities''': EDS, automated image mapping | ||
|- | |- | ||
|'''Sample Dimensions''': <3cm tall, no magnetic samples | |'''Sample Dimensions''': <3cm tall, no magnetic samples | ||
| Line 26: | Line 26: | ||
|'''Detectors''': Backscatter only | |'''Detectors''': Backscatter only | ||
|- | |- | ||
|'''Capabilities''': | |'''Capabilities''': EDS | ||
|- | |- | ||
|'''Sample Dimensions''': <2.5cm in diameter, <3cm tall, no magnetic samples | |'''Sample Dimensions''': <2.5cm in diameter, <3cm tall, no magnetic samples | ||
|} | |} | ||
A scanning electron microscope (SEM) uses an electron beam than scans across a sample, allowing for much higher magnifications compared to optical microscopy. The MILL currently owns two | A scanning electron microscope (SEM) uses an electron beam than scans across a sample, allowing for much higher magnifications compared to optical microscopy. The electrons are reflected off the sample (either elestically or ineleastically) and collected by a detector, yielding an image. The MILL currently owns two benchtop SEM systems: an older Phenom ProX and a new PhenomXL G2 (acquired May 2021). Both SEMs have backscattered electron detectors (BSD) for imaging and energy-dispersive X-ray spectroscopy (EDS) systems for elemental identification. The new PhenomXL contains an additional secondary electron detector (SED), which gives the images it captures better depth of field. | ||
==Theory== | |||
===Electron Imaging=== | |||
===Detectors=== | |||
===EDS=== | |||
<!-- | |||
==Phenom ProX SEM SOP== | ==Phenom ProX SEM SOP== | ||
The Phenom ProX Scanning Electron Microscope can take detailed images of samples. The maximum magnification is 40,000X to 100,000X and the device is capable of resolving features to <500 nm. Samples must be less than 2.5 cm in diameter and less than 3 cm tall. Additionally, energy-dispersive x-ray spectroscopy (EDX) can be performed on samples for elemental detection through point, line, and area scans. | The Phenom ProX Scanning Electron Microscope can take detailed images of samples. The maximum magnification is 40,000X to 100,000X and the device is capable of resolving features to <500 nm. Samples must be less than 2.5 cm in diameter and less than 3 cm tall. Additionally, energy-dispersive x-ray spectroscopy (EDX) can be performed on samples for elemental detection through point, line, and area scans. | ||
| Line 42: | Line 45: | ||
===Operating Principle=== | ===Operating Principle=== | ||
The SEM produces highly magnified images with a large depth of field. Samples placed within the SEM are scanned with a focused beam of electrons | The SEM produces highly magnified images with a large depth of field. Samples placed within the SEM are scanned with a focused beam of electrons. Since heavier atoms will backscatter electrons more strongly than lighter atoms, elements of a higher atomic number will appear brighter. Through EDS, the x-rays emitted from the elements are detected and analyzed to form a prediction of the elemental composition of the sample, and line and map scans can be performed. | ||
===Safety Procedures=== | ===Safety Procedures=== | ||
| Line 77: | Line 80: | ||
#*Close the door to the SEM. | #*Close the door to the SEM. | ||
For a video playlist with additional explanation of SEM operating procedures click [https://www.youtube.com/watch?v=F9jh7PNGqrw&list=PLuUTDbf8_YeL-z748VN6SejPdOToEacvE&index=2&t=0s here] | For a video playlist with additional explanation of SEM operating procedures click [https://www.youtube.com/watch?v=F9jh7PNGqrw&list=PLuUTDbf8_YeL-z748VN6SejPdOToEacvE&index=2&t=0s here]--> | ||
Revision as of 14:00, 26 May 2021
| PhenomXL G2 SEM |
|---|
 |
| Magnification Range: 360x to 190,000x |
| Feature Resolution: <500 nm |
| Detectors: Secondary (SED) & Backscatter (BSD) |
| Capabilities: EDS, automated image mapping |
| Sample Dimensions: <3cm tall, no magnetic samples |
| Phenom ProX SEM |
|---|
 |
| Magnification Range: 40,000x to 100,000x |
| Feature Resolution: <500 nm |
| Detectors: Backscatter only |
| Capabilities: EDS |
| Sample Dimensions: <2.5cm in diameter, <3cm tall, no magnetic samples |
A scanning electron microscope (SEM) uses an electron beam than scans across a sample, allowing for much higher magnifications compared to optical microscopy. The electrons are reflected off the sample (either elestically or ineleastically) and collected by a detector, yielding an image. The MILL currently owns two benchtop SEM systems: an older Phenom ProX and a new PhenomXL G2 (acquired May 2021). Both SEMs have backscattered electron detectors (BSD) for imaging and energy-dispersive X-ray spectroscopy (EDS) systems for elemental identification. The new PhenomXL contains an additional secondary electron detector (SED), which gives the images it captures better depth of field.