Term
| what is the purpose of a transformer in the x-ray circuit? |
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Definition
| vary voltage and current in the circuit |
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Term
| which type of transformer has more turns in the secondary coil than in the primary coil? |
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Definition
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Term
| what changes occur with voltage and current across a step up transformer? |
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Definition
-Voltage increases while current decreases.
-the change is proportional to the ratio of the number of turns in the primary coil to the number of turns in the secondary coil |
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Term
| what is the purpose of the step up transformer |
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Definition
| to provide voltage across the x-ray tube sufficient to produce x-rays |
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Term
| what is the purpose of the step down transformer |
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Definition
| provide filament amperage and voltage necessary for thermionic emission |
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Term
| in which of the two circuits is the step down transformer located |
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Definition
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Term
| in which circuit is the step up transformer located |
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Definition
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Term
| what type of transformer has only one winding and serves as a variable ratio transformer |
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Definition
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Term
| what is the purpose of the autotransformer |
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Definition
| varies incoming line voltage to an appropriate level |
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Term
| what is the purpose of the line voltage compensator |
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Definition
| corrects fluctuations in the line voltage |
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Term
| in half wave rectification, how many pulses of current per second will flow across an x-ray tube? |
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Definition
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Term
| in full wave rectification, how many pulses of current per second will flow across an x-ray tube? |
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Definition
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Term
| when 3 phase current is rectified, how many pulses per cycle are generated? |
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Definition
| six pulses per cycle als known as 3 phase |
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Term
| what is the main advantage of 3 phase generators over single phase? |
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Definition
| the voltage never drops to zero thus creating a near constant potential |
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Term
| to obtain similar results, what kVp adjustment should be made when going from single phase to 3 phase equipment? |
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Definition
| approximately 12% reduction (or almost half the mAs) |
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Term
| does mA help control the QUALITY or QUANTITY of x-ray photons? |
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Definition
| QUANTITY- increasing the mA provides more electrons available for x-ray production. |
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Term
| does kVp help control the QUALITY or QUANTITY of x-ray beam? |
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Definition
| QUALITY- kVp imparts the force that gives projectile electrons their kinetic energy.the energy will be converted at the anode so kVp changes help control the energy or the quality of the beam. |
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Term
| what is the purpose of the focusing cup? |
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Definition
| focus electron stream onto the focal spot at the anode |
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Term
| list 3 purposes of the anode |
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Definition
deceleration of electrons
electrical conductor
thermal conductor |
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Term
| what metals are used in an Anode? |
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Definition
| molybdenum with rhenium alloyed tungsten as the target focal spot |
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Term
| which type of x-ray photon results from projectile electrons braking, or slowing down, as they near the tungsten nucleus? |
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Definition
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Term
| which type of photon is formed as the result of a vacancy in an inner shell created by projectile electrons interacting with and ejecting an electron? |
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Definition
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Term
| what target material is often used in dedicated mammography tubes and why? |
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Definition
| molybdenum - emits a more uniform range of lower energy photons |
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Term
| why is the window of mammography tubes often composed of beryllium? |
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Definition
| absorbs less of the low energy beam than does glass |
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Term
| what term describes the physical area of the focal track that is impacted by the electron stream? |
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Definition
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Term
| what term describes the area of the focal track that is projected out of the tube toward the film? |
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Definition
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Term
| what effect does decreasing the target angle have upon effective focal spot size? |
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Definition
| decreases effective focal spot size |
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Term
| how many half value layers are needed to reduce an 80 mR beam to 10 mR |
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Definition
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Term
| which component of an image intensification tube converts x-ray photons to light photons |
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Definition
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Term
| which component of the image intensifier converts light photons to electrons? |
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Definition
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Term
| what is the purpose of the output phosphor? |
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Definition
| converts electron image to light image |
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Term
| what term defines a measurement of the increase in image intensity achieved by an image intensification tube? |
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Definition
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Term
| brightness gain is the product of what two factors? |
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Definition
| minification gain and flux gain |
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Term
| what is the range of accuracy for evaluating radiation field to light field congruency? |
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Definition
| plus or minus 2% of the SID |
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