RT 1303 REVIEW QUESTIONS CHAPTER 8 X-RAY PRODUCTION Where does the electron traveling from the cathode to the anode get its kinetic energy? Ans: From the high voltage How much of the kinetic energy is lost in the form of heat? Ans: 99% How does the anode handle all of the heat generated? Ans: Spread it over a large surface area rotating anode Larger anodes for high capacity output High rotation of the anode--10000 rpm vs. 3600 rpm Use of line focus principle Use tungsten 90%, and rhenium 10% to handle all of the hear produced Draw the heat quickly from the anodetube housing with cooling fans (Above questions were answered in ch.7) What are the two ways x-rays are produced? Ans: Brems X-ray production Characteristic X-Ray production Describe Bremsstrahlung X-Ray production Ans: The kinetic electron from the cathode is attracted toward the nucleus of the tungsten atom. When it turns toward the + charge of the nucleus, it releases kinetic energy in the form of electromagnetic energy, most of it in the form of heat, but some in the energy of x-rays. The energy of the x-rays is polychromatic, which means that the energy is from the applied KVP down to where it is heat, hence the use of the term KVP and not just KV. The average energy of the x-ray beam is 1/3 to of the applied kv and this is why we will need to use a filter to increase the mean energy of the beam. (next chapter) Describe characteristic X-Ray production Ans: The kinetic electron comes into the tungsten atom and if it has 69,.5 kv of energy, it can eject an electron from the k shell of the tungsten atom. This hole is filled from an outer shell electron. The excess kinetic energy of the electron is given up in the form of an x-ray. The energy of the x-ray depends upon where the two electrons came from.
RT 1303 REVIEW QUESTIONS CHAPTER 8 X-RAY PRODUCTION Where does the electron traveling from the cathode to the anode get its kinetic energy? Ans: From the high voltage How much of the kinetic energy is lost in the form of heat? Ans: 99% How does the anode handle all of the heat generated? Ans: Spread it over a large surface area rotating anode Larger anodes for high capacity output High rotation of the anode--10000 rpm vs. 3600 rpm Use of line focus principle Use tungsten 90%, and rhenium 10% to handle all of the hear produced Draw the heat quickly from the anodetube housing with cooling fans (Above questions were answered in ch.7) What are the two ways x-rays are produced? Ans: Brems X-ray production Characteristic X-Ray production Describe Bremsstrahlung X-Ray production Ans: The kinetic electron from the cathode is attracted toward the nucleus of the tungsten atom. When it turns toward the + charge of the nucleus, it releases kinetic energy in the form of electromagnetic energy, most of it in the form of heat, but some in the energy of x-rays. The energy of the x-rays is polychromatic, which means that the energy is from the applied KVP down to where it is heat, hence the use of the term KVP and not just KV. The average energy of the x-ray beam is 1/3 to of the applied kv and this is why we will need to use a filter to increase the mean energy of the beam. (next chapter) Describe characteristic X-Ray production Ans: The kinetic electron comes into the tungsten atom and if it has 69,.5 kv of energy, it can eject an electron from the k shell of the tungsten atom. This hole is filled from an outer shell electron. The excess kinetic energy of the electron is given up in the form of an x-ray. The energy of the x-ray depends upon where the two electrons came from.
RADT%201303%20Chpt%208%20Review%20Questions.docx