x ray tube construction

• Why is it important to understand the X-ray tube?

  It allows for safe and effective use of the equipment
• What does QC stand for in the context of X-ray tubes?

  Quality Control
• What is the relationship between wavelength and properties of electromagnetic radiation?

  Different wavelengths result in different properties
• How were X-rays discovered?

  By observing a faint glow on a screen when a Crookes tube was powered
• What happens to electrons in the X-ray tube?

  They are heated, released, accelerated, and crash into the anode
• What is the cathode in an X-ray tube?

  The negative end of the tube where electrons are emitted
• What material is the filament in the cathode made of?

  Tungsten
• What is thermionic emission?

  The liberation of electrons from an electrode due to temperature
• Why is the filament in the cathode designed as a coil?

  To increase the surface area for electron emission
• What is the function of the focusing cup in the cathode?

  To concentrate the electron beam towards the focal spot of the anode
• What material is the focusing cup typically made of?

  Nickel
• How does the negative charge of the focusing cup affect electron acceleration?

  It helps to accelerate the electrons towards the anode
• What happens to a cloud of electrons as they approach the anode?

  They tend to spread out due to repulsion
• How can the analogy of balls rolling down a hill be related to electrons in the X-ray tube?

  The hill represents the potential difference, and the balls represent electrons crashing into the anode
• What is the effect of rectification on the X-ray spectrum?

  It increases mean photon energy and reduces lower energy photons
• How does increased mean photon energy affect patient dose?

  It results in fewer low-energy photons contributing to patient dose
• What voltage is typically used for a chest X-ray exposure?

  125,000 volts
• Why is a vacuum necessary in the X-ray tube?

  To prevent electrons from interacting with particles that would scatter them
• What is the appearance of the anode in an X-ray tube?

  A disk at a slight angle that rotates
• Why does the anode rotate?

  To dissipate heat more effectively
• What percentage of energy is converted to X-rays during generation?

  Less than 1%
• What happens to the majority of energy during X-ray generation?

  It is lost as heat
• What is the formula for calculating heat produced in the X-ray tube?

  Heat (J) = w x kVp x mAs
• What does kVp stand for in the heat formula?

  Peak kilovoltage
• What does mAs represent in the heat formula?

  Current exposure time product
• Why is a higher heat capacity desirable for anodes?

  It allows for better temperature management during operation
• How can heat capacity be increased in the X-ray tube system?

  By increasing heat removal from the system
• What is the target material typically used in X-ray tubes?

  Tungsten
• Why is tungsten used as a target material in X-ray tubes?

  It has a high atomic number, high melting point, and good thermal conductivity
• What is the difference between stationary and rotating anodes?

  Rotating anodes dissipate heat better than stationary anodes
• Why are stationary anodes less common in general radiography?

  They have limited use and cannot handle high exposure rates
• What is the typical rotation speed of an anode disk?

  50 Hz
• What is the purpose of angling the target in an X-ray tube?

  To increase the area of heat distribution
• What is the focal spot in an X-ray tube?

  The area of the target impacted by electrons where X-rays are produced
• How does the anode angle affect the effective focal spot size?

  Larger angles increase the effective focal spot size
• What is the target stem made of in an X-ray tube?

  Molybdenum disk with a thin tungsten target
• Why is it important to minimize heat conduction to bearings in an X-ray tube?

  To prevent overheating and damage to the bearings
• What role does oil play in the X-ray tube?

  It acts to dissipate heat
• What is the purpose of the anode cooling chart?

  To show how long it takes for the anode to cool down
• Why is proper cooling time crucial for anode longevity?

  A worn anode could lead to inconsistent output and image quality