Actual Focal spot
The physical area of the focal track that is impacted.
Anode
The positive side of the x-ray tube, serves as a target surface for
high voltage electrons from the filament, conducts the high voltage
from the cathode back into the x-ray generator circuitry, and serves
as the primary thermal conductor.
Anode Assembly
Consists of the anode, stator. and rotor.
Anode cooling chart
Permits the calculation of the time necessary for the anode to cool
enough for additional exposures to be taken.
Anode heel effect
Due to the geometry of the angled anode target, the radiation
intensity is greater on the cathode side.
Cathode
The negative side of the x-ray tube; produces a thermionic cloud,
conducts the high voltage to the gap between the cathode and anode,
and focuses the electron stream as it heads for the anode.
Cathode assembly
Consists of the filament, focusing cup, and associated wiring.
Dual focus
A two-filament arragngement within the x-ray tube.
Effective focal spot
The area of the focal spot that is projected out of the tube toward
the object being radiographed.
envelope
The entire cathode and andoe assembly is housed within the glass or
metal structure.
Extrafocal radiation
Photons that were not produced at the focal spot; also called
off-focus radiation.
filament
A small coil of thin thoriated tungsten wire.
Focal point
The portion of the anode where the high-voltage electron stream will impact.
Focal spot
The portion of the anode where the high-voltage electron stream will impact.
Focal track
The portion of the anode where the high-voltage electron stream will
impact. when discussing a rotating anode, this describes the circular
path that will be impacted by the electron beam.
Focus
The portion of the anode where the high-voltage electron stream will impact.
Focusing cup
A shallow depression in the cathode assembly designed the house filament.
fractional focal spot
A very small focal spot usually a fraction of a fraction of a
millimeter in size.
grid-biased
A type of tube that quickly regulates the flow of electrons,
producing x-ray photons.
grid-controlled
A type of tube that quickly regulates the flow of electrons,
producing x-ray photons.
grid-pulsed
A type of tube that quickly regulates the flow of electrons,
producing x-ray photons.
Housing cooling chart
Permits the calculation of the time necessary for the housing to cool
enough for additional exposures to be made.
leakage radiation
Any photons that escape from the housing except at the port.
line-focus principle
Used to reduce the effective area of the focal spot.
off-focus radiaiton
Photons that were not produced at the focal spot; also called
extrafocal radiation
protective housing
The entire cathode and anode assembly is housed within this metal structure.
radiographic tube rating chart
A guide regarding the most common technical factor combinations that
can be used without overloading the tube.
rotating anode
An andoe assembly that turns during exposure.
rotor
A hollow copper cylinder or cuff that is attached to the anode disk
by a molybdenum shaft.
saturation current
as kVp increases, a greater percentage of the thermionically emitted
electrons are driven toward the anode.
space charge effect
As more and more electrons build up in the area of the filament,
their negative charges being to oppose the emission of additional electrons.
stationary anode
An anode assembly that is immobile
stator
Induction-motor electromagnets that turn the anode
target
The portion of the anode where the high-voltage electron stream will impact.
tube rating chart
provides a guide regarding the most common technical factor
combinations that can be used without overloading the tube.
window
A structure where the primary x-ray beams exits the envelope, which
allows less absorption or scatter of photons.