Production of X-rays part 1 Flashcards
What are the two parts of the tubehead?
x-ray tube
power supply (generator)
What buttons are on the control panel?
Exposure time, kVp and mA selectors
What type of exposure button do we use?
dead-man type (if you take finger off it stops exposure)
What three things are required on the control panel?
- dead-man type exposure button
- indicator light
- audible signal
What is in the tube head?
Power supply + x-ray tube
What transformer is on the cathode (-) side?
step-down transformer
What transformer is on the anode (+) side?
step-up transformer
X-rays are produced by the anode or cathode?
anode
Electrons are produced by the anode or cathode?
cathode
What does the step-up transformer do?
raises voltage
What does the step-down transformer do?
lowers voltage
What are the parts of the tube head besides the power supply and x-ray tube?
◦ Glass envelope
◦ Insulating oil
◦ Metal housing
◦ Tube window
◦ Aluminum filters
◦ Lead collimator
What does the insulating oil in the tube head do?
disperse heat
What does the lead collimator do in the tube head?
determines final shape of the x-rays
What do the aluminum filters do in the tube head?
filters the x-rays that are not useful (don’t go to patient)
What is the space called inside the x-ray tube?
vacuum
What are the two main parts of the cathode (-)?
filament
focusing cup
What is the filament made of?
tungsten
What is the focusing cup made of?
molybdenum
What is the source of electrons?
filament
How does the filament generate electrons?
Is heated with a low voltage source and emits electrons at a rate proportional to its temperature (thermionic emission)
What is the charge of the focusing cup?
negative charge
What does the focusing cup do?
Focuses the electrons into a narrow beam directed to the focal spot (+)
What is thermionic emission?
emits electrons at a rate proportional to its temperature