what is the anode? what does it include?
its where xrays are produced.
includes anode disk, rotor, and stator
what charge is the anode
positive
where are xrays produced in the anode
target surface, tungsten
where is excess charge sent
high volt generator
what does it mean that the anode is the primary thermal conductor
90% of elecs from filament produce heat
what is the focal spot
region of the anode target in which electrons interact to produce xrays
aka focal track
what is the purpose of copper and molybdenum in an anode?
conducts heat away from anode surface
what is the difference between a stationary and rotating anode
s- doesnt move, tungsten is in the middle and target for xray production
r- has a molybdenum neck thing, has a focal track which produces xrays, and tungsten is an anode disk
what is the target angle for stationary anodes? where are they mainly used
45 degrees
dental units
how big is the anode disk? what does it contain?
5-13 cm in diameter
contains tungsten rhenium target area, and a molybdenum or graphite backing
why is rhenium added to tungsten?
allows the target to expand as it heats
why is molybdenum used as the back and stem of anode
because it doesnt expand when heated so it prevents anode from breaking cause it gets so hot
why is graphite used in anode
decreases the weight of the anode so it spins faster
where is SID measured from
focal spot
what are the 3 reasons why tungsten is used as the target material?
1- atomic #, good for xray production in diagnostic range
2- thermal conductivity, dissipates heat well
3- high melting point, results in minimal damage to anode
why do anodes need high heat capacity? what allows it to have good heat capacity?
cause the process of making xrays generates a lot of heat.
as the anode spins the focal spot is stuck my electrons creating heat spread over a large area, the rotation allows for higher heat capacity and the faster the better
is it better for heat to be spread over a larger or smaller area, why?
larger, prevents damage
how big is the small and large focal spot
sm- 0.5 mm- 1.0 mm
lrg- 1.0 mm - 2.0mm
what is focal spot blooming
as the tube ages rhe focal spot size increases due to wear. this causes blurry images because elecs are hitting the anode outside of the focal spot
what are 3 things about the cathode that affect focal spot size
1- size of filament
2- shape of focusing cup (determines elec stream shape)
3- position of filament in focusing cup
why do some anodes have slits? what are they used for?
1- allows for expansion of metal without cracking anode.
2- used in CT or interventional high exposures
what forms an electromagnetic induction motor? what does it do?
1- the stator and rotor
2- used to spin the anode
where is the stator located? what is it composed of? what kind of current does it use?
1- outside envelope and vacuum but still in tube housing.
2- electromagnets
3- alternating current which creates magnetic field that causes the rotor to spin (this is why its not in envelope)
what makes the rotor spin? what does that cause to happen?
1- stator, or specifically the coils in the stator.
2- stator causes rotor to spin which causes anode to spin
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M1 L18
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M1 L2 basic elements6
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M1 L334
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cathode36
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anode30
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line focus principle M1L623
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anode heel effect M1L714
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tube preservation21
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M2 L1 scatter19
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M2 L2 collimator31
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M2 L3 intro to grids26
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M2L4 grid formulas14
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M2 L523
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M2 L6 grid errors14
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M3 L1 & 231
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M3 L3 & 416
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M3 L520
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M4 L1 & 230
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M4 L315
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M4L4 & questions from review15
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M5 L1, 2, & 329
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M5 L423
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M5 L5-732
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M6 L1-338
