X ray tube- Ch. 6

kkaitlyn96's version from 2016-11-21 01:10

Section 1

Question Answer
Purpose of the x ray tubeto create photons and x radiation
Assembly of the x ray tube cathode, anode, glass envelope, protective housing
Cathode functionfocus electron stream as it heads for the anode
Contents of the cathodeassociated wiring, filament, focusing cup
filamentsmall coil of thin wire
Filament thick, wide, long0.1- 0.2mm thick, 1-2mm wide, 7-15mm long
Filament material and whyTungsten, high melting point, high atomic number, difficult to vaporize
Most x ray tubes are _________ focusdual
Filament functionprovides the right amount of resistance to make thermionic emission
Focusing cup made out of Nickel
Purposeseparate circuit to create negative charge to outside
Space charge effectthe electrons build up and the negative charges start opposing eachother

Section 2

Question Answer
Function of Anodetarget
The anode serves as the primary thermal conductor
Anode material and whyTungsten, high atomic number, high melting point, heat conducting ability
Stationary anodeembedded at 45 degrees
Rotating anodeembedded at 12 degrees
Line focus principleeffective focal spot is smaller than the actual focal spot
The statorinduction motor sits outside of glass envelope, only in rotating anode tube
The rotorinside glass envelope, makes rotor turn
EnvelopePyrex, oil is inside and out, oil is an insulator

Section 3

Question Answer
Housing controls leakage and scatter radiation, protects us from radiation
Leakage radiationcomes out of the tube not through the window
Off focus radiationany photons not created at the focal spot or track
Heat unitsmA* kVp*time*rectification constant
1 phase rectification constant1.00
3 phase 1.40