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How many electrons are emitted by X-ray
- two electrons
- source electron
- Ejected electron
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What does X-ray depend on
atom atomic number
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How many spectra does X-ray produce?
- two major series type
- K series
- L series
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Bohr Atomic Model Explains ...
- Spectra of Hydrogen
- Energy of atom is related to the distance of electron from nucleus
- energy of atom is quantized
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atom can only have certain specific energy states called
Quantum levels or energy levels
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X-ray analysis is ___________ for the sample and X-ray spectrum is _________ complex than optical sepctra
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___________ determines wavelength used for anlaysis
accelerating voltage
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what is theta?
Anlge between incident beam and the lattice planes
-
it is _________ that determines the identity of elements in a sample
Wavelength
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Common metal used in X-ray
Cu,W,Mo
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Which part of the x-ray source causes the emission
Target, Anode
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What is Collimeter
it is a series of metal plates with holes in the middle. it is designed to absorb all X-rays not traveling in the proper direction.
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Why normal grating or prism can not be used
- X-ray would either pass through or be absorbed
- no dispersion
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Disperser is a single crystal mounted on a rotatable table
Goniometer
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The entire spectrum is disperesed simultaneously (T/F)
False
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As the crystal rotates ______, th edetector is rotated _____ to keep the detector in line with the _____-
- Theta
- 2theta
- Diffracted radiation
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What is the difference between XRD and XRF?
In XRD the electron are bounced off while in XRF wavelength is being emitted
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X-ray reads Carbon atom (T/F)
False
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Ionization Detector Contains________-,__________,______, and Solid state Detector contains________,_________,and________
- Ionization chamber, proportion Counter, Geiger muller Tube
- Fluorescent Screen, Scintillation Counter,PMT detector
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What gas is used in ionization detector
Argon
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Ionization Detector does not discriminate between different radiation (T/F)
True
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In the semiconductor Detector, the detection is base on ...
Based on the current required to re-establish the depletion zone
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What is the difference between WD-XRF and ED XRF Analysis?
- WD-XRF has X-ray tube, Sample holder, Crystal, and detector. Wavelength is detected.
- Detector can detect up to 24 element simultaneously
- ED-XRF has only x-ray tube and sample holder. energy is being detected instead of wavelength.
- Detector is sequential or Simultanous
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Which XRF analysis has greater resolution and better S/N ratio?
WD-XRF
-
LLD
Typical limits of detection
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X-ray can be scattered by the planes in a crystal, resulting in both __________ and _________ interference
- Constructive( results in diffraction)
- Destructive
-
Provides information on structure and chemical make up of materials
XRD Methods
-
The repetitive patterns of the unit cell result in _________ that _______ x-rays
- Diffraction planes
- Diffract
-
Atoms located exactly on a crystal plane produce _______- diffraction
Maximum
-
Atoms located halfway between planes produce ____________- interference
Maximum destructive
-
What is Bragg's Law of Diffraction?
- When an xray stikes a crystal, some of the xrays are scattered by the atoms at the surface
- others penetrate the second layer of atoms where more scattering occurs
- this scattering results in diffraction and will only occur if the distance between atom layers is approximately the same as the wavelength of the xray
-
A ____________ may be used instead of film to yield exact _____ data
- Scintillation Counter
- Intensity
-
Parallel beam optics generated through..
Gobel mirrors
-
Where does Gobel mirror located
- Between Xray tube and sample
- it will result in parallel beams to hit the sample
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what kind of informatin can be obtained from a powder diffration pattern?
- Peak Position ------------------- dimention of the unit cell
- Peak intensity-------------------- content of the unit cell
- Peak broadening----------------- Strain/crystallite size
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