Stationary and Rotating X-ray Tube Flashcards
It surrounds the x-ray tube and it is made of pyrex glass
Glass Envelope
Why does glass envelope is thinned at exit window?
To permit exit of on-focus photons
It is the negative side of the x-ray tube.
Cathode
How many filaments are present in focusing cup?
One or two filaments
When cathode is heated, electrons are emitted from the filament which is called ___
Thermionic Emission
Released electrons are directed towards anode for ____
Photon Production
It is the two cathode filaments.
Dual Focus
Two types of Cathode Filaments
Small which is 1cm long for small mA, small parts and small exposures.
Large which is 2cm long for large mA and lower resolution.
It is the positive side of the x-ray.
Anode
Anode absorbs ___ and creates ___.
Anode absorbs electrons and creates x-rays.
This is where x-rays are created.
Anode
Two types of Anode
Stationary and Rotating
What is stationary?
The electron beam is focused in one small area and all of the heat was there.
It has simple design, low heat capacity and low exposures.
What is rotating?
Spreading out those electrons in larger areas and increasing the heat of the tube.
It has complex design, high heat capacity and high exposure.
It turns the anode without contacting on it and it induces the anode to spin.
Induction Motor
It is the only component of xray tube that is outside the glass envelope. It is an electromagnet that causes rotor to rotate.
Stator
It is made of copper and it rotates due to magnetic field of stator. Its tube is attached directly in disk.
Rotor
It is silver plated metal balls which act as lubricant for rotating rotor. It has low friction that allows free rotation of rotor.
Bearings
It is a metal or lead housing that prevents x-ray from being emitting throughout the exam room.
Tube Housing
It creates an airfree vacuum around the cathode and anode to prevent from oxidation.
Glass Envelope
