Term
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Definition
| kVp x mA x time x rectification constant |
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Term
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Definition
| As more and more electrons build up in the area of the filament, their negative charges begin to oppose the emission of additional electrons |
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Term
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Definition
| Where the intensity of radiation is greater on the cathode side |
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Term
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Definition
| The ejection of electrons from the surface of the wire due to increased heat, causing an electron cloud (also called space charge cloud) |
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Term
| Describe what it means when the x-ray tube is gassy. |
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Definition
| A small percentage of electrons are permanently vaporized from the filament and they contribute to reducing the vacuum, thus making the tube gassy. |
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Term
| What is responsible for the noise during rotor acceleration? |
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Definition
| Long use at high temperatures causes the ball bearing to become imperfectly round. |
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Term
| Describe the focusing cup and what it does. |
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Definition
| A shallow depression in the cathode assembly designed to house the filament. |
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Term
| What is the primary purpose of the focusing cup? |
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Definition
| To narrow the thermionic cloud as it is driven towards the anode. |
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Term
| Atomic number of tungsten? |
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Definition
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Term
| What part of the anode assembly is located outside the glass housing? |
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Definition
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Term
| What is the maximum allowable radiation leakage from the tube, according to the NCRP? |
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Definition
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Term
| What is the primary purpose of the tube glass housing? |
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Definition
| Maintain the vacuum between the cathode and the anode. |
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Term
| What material is used for the anode target area? |
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Definition
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Term
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Definition
1. High atomic #
2. High melting point
3. Heat conducting ability |
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Term
| What material commonly makes up the target for mammographic units? |
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Definition
| Beryllium, to avoid attenuating the lower-energy photons. |
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Term
| Where do you measure the "source" when measuring for SID? |
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Definition
| The exact point at which photons are created. The target is considered to be a source point. |
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Term
| What happens if the stator or rotor malfunction? |
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Definition
| Electron stream overheats the target area of the anode focal track. Melting might occur, tube will be destroyed. The end of civilization as we know it! |
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Term
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Definition
| A small coil of thin thoriated tungsten wire. |
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Term
| What are some desirable characteristics of the material used for filament? |
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Definition
| High melting point and difficult to vaporize. |
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Term
| Cathode end of the tube is what charge? |
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Definition
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Term
| What type of charge does anode have? |
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Definition
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Term
| Why is a rotating anode desirable over a a stationary anode? |
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Definition
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Term
| What is a spinning top test used for? |
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Definition
1. timer accuracy
2. rectifier failure |
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