generators and components Flashcards
wavelength and frequency of a wave are ___ proportional
inverseley
velocity is equal to the ___ ___ ___
speed of light
if frequency increases, then wavelength ____
decreases
___ ___: the x-ray examination room appearance can vary from establishment to establishment
x-ray suite
x-ray machines consist of 3 basic components
operating console
high voltage generator
x-ray tube
most x-ray imaging systems are designed to operate on ___v power
220
electricity in the walls is __v
120
the ___ ___ measures the voltage provided to the x-ray machine and adjusts that voltage to exactly 220v
line compensator
line compensators are used to regulate the ___ in the machine
voltage
___ ____ refers to the number of x-rays or intensity of the x-ray beam
radiation quantity (mAs)
radiation quantity is expressed in ____ or ____
milliroentgens
milliampere-second
___ ___ refers to the penetrability of the x-ray beam
radiation energy (kVp)
radiation energy is expressed in ___ ___
kilovolt peak
radiation quantity can be though of how many x-rays are ___
made
radiation energy can be thought of as how likely the x-rays are to ___ the patient
penetrate
if you increase the radiation energy then you are ___ likely to penetrate
more
the operator is able to directly control the ___ and __ on the console
mAs
kVp
the number of x-rays that reach the image receptor is directly related to both the x-ray tube ____ and the ___ that the tube is energized
current
time
most active machines today are equipped with electronic timers controlled by a ____
microprocessor
____x_____= mAs
sec x milli-amperes
automatic exposure control is used with ___ ___
digital radiography
digital radiography measures the quantity of radiation that reaches the ___ ___
image receptor
digital radiography automatically ____ the exposure when the receptors receives the required ____
terminates
intensity
in order to produce x-rays, a very high voltage potential has to be reached and the current must be ____
direct
for the current to be direct, there needs to be a high voltage _____ and a voltage _____
transformer
rectifier
the voltage rectifier allows the current to flow in ___ directly
1
voltage rectifier converts ___ current to ____ current
alternating
direct
converting alternating current to direct current is accomplished by using ____
diodes
the electricity in the walls is an ____ current
alternating
a very small amount (~__%) of the energy used to prodocue an x-ray is converted in to ____
1
x-rays
the energy that is not used to make the actual x-ray (__%) is essentially wasted as ___ ___
99
heat energy
___ ___ is often a limiting factor as to how many x-rays can be made in a single exposure
heat energy
alternating current generator has a ____% ripple
100
single phase half rectified generator has a ___% ripple
100
single phase full rectified generator is ____% ripple
100
alternating current has an ___ and ___ appearance
up
down
single phase half rectified generators’ wave is the same as alternating current, however, the wave at the bottom is ___ ____
cut off
single phase full rectified generator has the same appearance as alternating current however the bottom wave is ___
inverted
triple phase full rectified generator is ___% ripple
14
Triple phase full rectified generator’s wave is ___ and ___
tripled
flipped
high frequency generators have a <__% ripple
1
every generator is direct current except _____ ____
alternating current
the lower voltage ripple, the greater x-ray ___ and ___, as a result of more constant voltage supplied to the tube
quantity
energy
energy/quantity is ___ related to % of ripple
inversely
when xrays are produced, they are emitted ____
isotropically
____: equal intensity in all directions
isotropically
we only use x-rays that are emitted through the ___ of the tube
window
the x-ray that is emitted through the window of the tube is known as the __ beam or __ beam
useful
primary
____ ____: x-rays that escape through the protective housing
leakage radiation
__ housing with ___ lining is used to prevent leakage radiation and electric shock
steel
lead
leakage radiation must not exceed __mR/hr at 1 meter
100
x-ray tube is where the x-rays are ___
created
internal omponents of the x-ray tube is composed of the ___ and ___
cathode
anode
the x-ray tube is an electronic ___ tube with components contained in a __ or ___ enclosure
vacuum
glass
metal
the __ of the x-ray tube allows for more efficient x-ray production
vacuum
___ in the enclosure of the x-ray tube reduces electron flow from the cathode to the anode
gas
as a tube ages, ___ vaporizes and coats the inside of the glass enclosure
tungsten
newer models and virtually all high capacity x-ray tubes now use ___ enclosures
metal
___: thermionic emission occurs here
cathode
___: site of x-ray production
anode
___ is negatively charged
cathode
cathode holds the ___ in a focusing cup
filament
in the cathode, electricity circuit sends ___ to the filaments, which heats up to the point of boiling off a ___ of ___; this process is known as ___ ___
electrons
cloud of electrons
thermionic emission
filament in the cathod is usually made of ___ __
thoriated tungsten
tungsten provides for a higher ___ ___ than other metals because its boiling point is ____
thermionic emission
3410
the focusing cup is __ charged
negatively
focusing cup is used to direct negatively charged electrons into a ___ area on the target
smaller
___ ___: the cloud of electrons produced at the cathode
space charge
the build up of negative charge makes it difficult for subsequent electrons to be emitted by the filament due to ___ ____
electrostatic repulsion
2 filaments: 1 ___ and 1 ____
small
large
small focal spot is used when ___ spatial resolution is required
better
large focal spot is used when ___ body parts are imaged
large
the anode is ___ charged, drawing the electrons from the cathode ___ it
positively
toward
x-rays are created when electrons are shot over from the cathode and ___ into the anode
SLAM
2 types of anodes
stationary
rotating
___ anodes are sued in x-ray units in which high tube current and power are not required
STATIONARY
rotating anodes are able to produce ___ energy x-rays and __ exposure time because of more ___ ___ and ___ ___
higher
shorter
surface area
heat dissipation
3 functions of the anode
electrical conductor
mechanical support
thermal dissipator
___ is the area of the anode struck by the electrons from the cathode
target
in the stationary anode tube , the target is embedded in the ___
anode
in the rotating anode tube, the target is the ___ ___
rotating disc
the target of the anode is made of ___
tungsten`
the target of the anode is made of tungsten because of 3 things
atomic number
thermal conductivity
high melting point
___ ___ effect is the result of the line focus principle that distributes radiation intensity more on the cathode side than on the anode side
anode heel
the x-rays that are emitted through the “heel” of the anode are ___ in intensity because they have to travel a ___ path through the anode
reduced
longer
the difference in radiation intensity across the useful beam of an x-ray field can vary by as much as ___%
45
in general, the anode portion of the tube should be oriented over the ___ portion of the anatomy
thinner
anode heel effect is altered by 3 main factors:
anode angle
distance
x-ray field size
the smaller the anode angle, the ___ the heel effect
greater
the shorter the distance of the anode heel, the ___ the heel effect
greater
the larger the field size of the x-ray, the ___ the heel effect
greater
the rotating anode is powered by an ___ ___ ____ which has 2 principle parts separated from each other by the glass or metal enclosure
electromagnetic induction motor
what are the 2 principle parts to the induction motor
stator
rotor
___ is the part of the induction motor outside the enclosure
stator
___ consists of a series of electromagnets equally spaced around the neck of the tube
stator
__ is the part of the induction motor that is the part inside the enclosure
rotor
___ consists of a copper/iron shaft
rotor
