Tube head functions Flashcards
What is the function of the lead case/lining
Inner case that is made of lead surronds tube head. Ensures x-rays do not escape, lead absorbs any radiation
What is the function of the glass envelope?
A glass vaccum tube that contains the anode an cathode of the x-ray tube
What is the function of the vacuum?
A vacuum is a space in which all the air and gasses have been extracted, the function is to allow the x-rays to travel in a straight line, if air or oxygen were present the x-rays would bounce of the particles and be misdirected
What is the function of the cooling fins?
To disperse the heat
What is the function of the focusing cup?
A recessed area wher the filament lies, directing the electrons toward the anode. The focusing cup is made of molybdenum
What is the function of the filament?
Part of the low-energy circuit in the cathde that, when heated releases electrons from their orbit
What is the function of the target?
it is the anode
What is the function of the copper stem?
acts as a conducter of heat and draws the heat away from the tungsten target
What is the function of the oil?
Transfers heat away from the anode (in heavy duty radiography the oil in the tube housing is often circulated through a heat exchanger
What is the function of the aluminium filament?
Flat sheet of aluminium covering window which absorbes any soft x-rays
How are x-rays produced?
Within the tube head there is a cathode (-ve) and anode (+ve). The cathode consist of a filament made of tungsten. The filament is heated by an electric current which produces electrons. These electrons are released by thermionic emission. The electrons are directed by the focussing cup to the anode. The elctrons travel at high speed across the tube from the cathode which is negatively charged to the positively charges anode (target area). Electrons hit the target are and produce 1% x-rays and 99% heat.
