LRA FINAL QUESTIONS WITH CORRECT ANSWERS RATED A+

1. Leakage radiation must not exceed: Less than 100 mR/hr. 2. What are the key determinants of x-ray production: nuclear binding energy and electron binding energy 3. Anode: The anode is the positive end of the tube. It provides the target for electron interaction to produce x-rays and is an electrical and thermal conductor. Designed to dissipate heat 4. A rotating anode is made up of: A rotating tungsten-coated (high atomic number) molybdenum disc mounted on a copper shaft with a molybdenum core 5. Size of target window: Usually 5cm squared 6. The x-ray tube is situated in a: Protective housing 7. What is the glass envelope made of: Borosilicate glass (Pyrex) because it is heat resistant 8. Tungsten: Has a high atomic number that can withstand heat 9. Stator: The stator is made up of electromagnets arranged in pairs around the rotor. The stator is outside the tube enclosure. 10. Rotor: The rotor is made of an iron core surrounded by coils and located in the center of the stator but within the enclosure. The rotor does not touch the stator, nor is it supplied with electric current. It is operated through mutual induction. 11. Cathode: Negative end of the tube. It provides the source of electrons needed for x-ray production. The cathode is made up of the filaments and the focusing cup 12. Which component of the x-ray tube is responsible for concentrating the electron cloud: Focusing cup 13. The x-ray tube is part of the: X-ray circuit secondary 14. Thermionic emission: The process of electrons being burned off of the filament 15. What is the target window designed for: The desired exit point of the x-rays produced. The target window is fashioned to minimally interfere with (absorb) the x-rays 16. The intensity of the x-ray beam is more: On the cathode side 17. What reduces leakage radiation to required standards: Protective housing 18. The term space charge within the x-ray tube refers to: Free electrons 19. What makes up the cathode: Dual-focus tubes (2 filaments) Focusing cup 19 Molybdenum: Used as the disk base and core because it has a low thermal conductivity and it is a light but strong alloy 20. Housing: A protective housing provides solid mechanical support 21. The protective housing is made up of: -Lead lined structure • -Oil bath (99% heat, 1% x-ray) • -Cooling fans • -Electrical insulation • -Large cables • -Absorbs stray photons 22. Electromagnetic radiation: A form of energy that originates from the atom, can exist apart from matter and travel through a vacuum 23. The relationship between wavelength and frequency is: Inverse 24. Wavelengths are measured in: Meters, from crest to crest 25. Frequencies are measured in: Hertz, how many waves in a timeframe 26. Electromagnetic radiation is characterized by: How it interacts with matter 27. X-rays originate through: Interactions between electrons and atoms 28. Amplitude: Height of a wave 29. Ionization: Removal of an electron from an atom 30. The metal envelope variety provides: Constant electric potential between the electron stream from the cathode and the enclosure, thereby avoiding the arcing problem and extending tube life 31. The area where incident electrons strike the anode: Actual focal spot 32. The width of the x-ray beam as it's projected toward the patient from the anode is called: Effective focal spot 33. The smaller the effective focal spot: The sharper the image will be