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19 Cards in this Set
- Front
- Back
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How do we generate X-ray for XRD? |
We bombard a source with electrons from a heated filament to generate electrons.
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Why is the X-ray emission characteristic for a material |
It is based on the different energy levels |
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What are the health risks of X-rays? |
DNA mutation |
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How does a soller slit operate? |
Ensures all x-rays are parallel by passing through a stack of parallel plates |
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What shape is a Goebel mirror? |
Parabolic |
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If we apply a filter, should the material have a larger or smaller atomic number? |
Smaller |
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Why is a monochromator detrimental to operation sometimes? |
Not enough intensity |
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How do we detect X-rays? |
Developed on a film or sensor based on pn junction. |
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How does the Edwald sphere utilize the wavelength? |
Radius of the sphere is 1/wavelength |
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In our Edwald sphere, what rotates as we scan? |
The crystal rotates. |
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What does FWHM stand for? What is it used to calculate? What is the limit |
Full Width at Half Maximum. It is used to calculate particle sizes greater than 200 nm. |
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Why is their a limit on the particle size we can calculate? |
Intrinsic broadening of the XRD machine. |
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What does XRR stand for, what information does it give? |
X-ray reflectivity and surface roughness? |
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When a stressed object (being pulled apart) is analysed under XRD, how do peaks change. |
Shift to lower angles as their is a larger distance. |
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What does XRR measure? |
Thickness of sample and roughness
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What will a polycrystalline diffraction pattern look like? |
Concentric rings |
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Is it easier to position the detector for single crystals or polycrystals |
Poly Crystals |
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Why do amorphous samples show XRD peaks? |
Amorphous crystals have short range order |
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What is structural extinction? |
Certain angles that satisfy the Bragg condition, will not show up in peaks due to destructive interference |
