rad 103 exposure 2

what are the two main parts of the xray tube

anode and cathode

purpose of cathode

produce electrons

main parts of cathode

filament and focusing cup

what is filament made of

tungsten

purpose of focusing cup

focuses electrons onto the anode

anodes charge?

positive

cathodes charge

negative

what is the focusing cup made of

molybdenum

area electrons strike anode

focal track

three things needed to make x-rays?

electrons, something to push the electrons, a way to suddenly stop the electrons

thermionic emission

electrons are boiled off from the filament forming a space charge

space charge

cloud of electrons around filament

rotating part of the tube

anode

why is the envelope coated in lead

absorb leakage radiation

isotropic

goes out in all directions equally

focal spot affects

spatial resolution

kinetic energy is turned to

electromagnetic energy

1st step in xray production

heating filament

1

glass housing

2

filament

3

anode

4

focal spot

6

electrons

7

xrays

8

focusing cup

9

window

10

space charge

how many filaments usually are there

two

focusing cup gets a very strong ____ charge

negative

anode gets a very strong ___ charge

positive

what percent of of electrons turn into heat

99%

what percent if electrons turn into xrays 1%

small focal spot

increased spatial resolution

large focal spot

withstand higher heat load and can use higher ma, kvp, and time

leakage radiation

all radiation that comes out through the tube housing and not the window

xrays are created in what fashion

isotropic

what energy is turned to xrays

kinetic energy

heat filament

negative charge, controlled by mAs

anode function

pulls or attracts negative electrons

primary radiation

wanted radiation that comes through the window

scatter radiation

when radiation hits an object, it bounces off and goes in another direction