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17 Cards in this Set
- Front
- Back
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The source of free electrons is?
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Thermionic Emission
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What creates Thermionic Emission?
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The source of electrons is provided by a filament. An electric current flows through the filament to heat it. Heat speeds up the movement of electrons in their orbit and increases their distance from the nucleus. Electrons in the outermost orbital shells move so far from the nucleus that they are no longer held in orbit, but are free (in air) forming an electron cloud around the filament
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What creates an acceleration of electrons?
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A high voltage--provides acceleration of electrons
A high positive electrical potential at the target attracts the negatively charged electrons |
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What is the focusing cup? And what does it do?
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It focuses the electron stream to a point on the anode and it is found behind the filament
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The kinetic energy of the electrons is converted into what types of energy?
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99% heat and 1% x-ray
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What are the two types of radiation?
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Bresstrahlung and Characteristic Radiation
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What makes up the majority of radiation?
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Bresstrahlung
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X-ray beams have what frequency and what wavelength?
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High frequency and Short wavelength
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Quality is determined by what?
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kVp
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Quantity is controlled by what?
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mAs
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X-ray beam that leaves the tube and is unattenuated?
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Primary Beam
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What remains of the primary beam after it has been attenuated by matter
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Remnant Radiation
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What is the inverse square law?
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The relationship between Sourse to Image Diestance and the intensity of the beam I1/I2=(D2)2/(D1)2
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What are the fundamental properties of x-rays
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they travel in straight lines and they ionize matter
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What are the different photon interactions with matter?
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Compton effect
Photoelectric absorbtion Coherent (classical or Thompson's) |
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What is the most common photon interaction with matter?
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Compton effect. Responsible for most scattered radiation
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Anatomic structures that have higher atomic numbers will absorb less radiation? True or False?
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False. High atomic numbers will absorb more radiation.
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