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Which of the following are true regarding the production of X-ray photons when using a tungsten target? a. The majority of X-rays emitted are a result of characteristic radiation b. The kinetic energy of electrons (keV) interacting with the target is equal to the kV between the anode and cathode of the X-ray tube c. Filament electrons with 90 keV can dislodge K-shell electrons in the target d. The energy of Ka radiation is greater than Kb radiation e. L-shell radiation makes up 25% of characteristic radiation emitted from the tube |
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Answer» a. False. Approximately 80% of X-rays emitted by a tube are Bremsstrahlung radiation. b. True. c. True. The kinetic energy of filament electrons needs to exceed the binding energy of K-shell electrons (70 keV for tungsten). d. False. For tungsten: Kα radiation = K-shell binding energy (70 keV) – L-shell binding energy (12 keV) = 58 keV. Kβ radiation = K-shell binding energy (70 keV) – M-shell binding energy (2 keV) = 68 keV. e. False. As the binding energy of L-shell electrons is equal to 12 keV, the photon energy produced when an electron from an outer shell occupies the gap is too small to leave the tube (i.e. less than 10 keV). |
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