final notes Flashcards
what three characteristics are needed to describe a photon?
velocity, frequency and wavelength
The longer the wavelength the__
the lower the frequency
The shorter the wavelength the __
the higher the frequency
Frequency x velocity =
wavelength
the distance between two crests in a wave __
wavelength
the number of crests or cycles per second __
frequency ** measured in hertz**
What is kinetic energy?
energy in motion
As ___ increases, both intensity and energy are increased
kinetic energy
unit of electrical charge
coulomb
unit of electrical potential
volts
unit of electrical current
amperage
unit of electrical resistance
OHMS
unit of electrical power
watts
Electrostatic force is measured in__
newtons
Resistance depends on?
material, length, cross sectional area and temperature
Most used and advanced transformer, both primary and secondary coils wound around a central core for maximum effiency
shell type
What voltage is needed to drive electrons across the tube with sufficient speed?
30,000-150,000 /30 to 150kv
constant high voltage showing 6 pulses per second 1/60 sec
three phase
single phase ripple
100%
3 phase, 6 pulse ripple
13% –voltage never falls below 87%
3 phase 12 pulse rippl
3.5% voltage never falls below 96.5%
high frequency ripple
less than 1%
x-ray tube acts as rectifier, no diodes, 100ma to 100kvp, used in dental offices
self rectification
1 or 2 diodes, out puts 60 pulses per second
half-wave
used in all stationary x-ray machines, positive voltage always impressed across tube, atleast 4 diodes
full rectification
Only allows current flow when higher potential placed on the P-side
p-n junction
Loosely bound electrons (arsenic or phosphorus doped)
N-type
contain electron traps (gallium or boron doped)
P-type
the x-ray tube window is how many cm?
5 cm squared
thermionic emission is controlled by?
filament current
Focusing cup works on__
electrostatic repulsion
Electrical conductor, thermal conductor, mechanical support
anode
Thermal conductor ____% of kinetic energy is heat and __% energy is x-rays
99% and 1 %
Rotating anode target angle ranges from
5-15 degrees
Anode diameter is __ larger= increases workload
3-5 inches
The lower the target angle the ___ the____, the greater the hear load
smaller, effective fss
Vacuum tube is made of
pyrex
tungstens high melting point is
3410 C
A filament made of and is how big?
tungsten, 2mm diameter 1 or 2 cm long
When electrons interact with target atoms at various depths
heel effect
radiation intensity is greater on the cathode side
heel effect
The heel effect is less pronounced at ?
increased SID, as size of film decreased, larger FSS
The image intensified is located where during flouro?
above table
The x-ray tube is located where during flouro?
under table
The x-ray tube is operated at less than ___ mA during flouro
5 mA
Brightness gain is
the ability of image itensifier to increase the illumination level of the image
Brightness gain =
minification gain x flux gain
Receives remnant x-ray beam
converts it into light
converts light into electron image
Finally conversion of electron image back to light image of increased brightness
Image intensifier tube
when high energy electrons interact with the image intensifier screen, the output phosphor, it produces how much light
5000 to 20,000 brighter
what is flux gain?
increase in brightness due to acceleration of electrons
what is minification gain?
increase in brightness as a result of minification of the image
The unit of electrostatic charge is ?
coulomb
The unit of electrostatic force is ?
newton
Normal power supple in US is
120 V , 60 hz single phase
P= IV
power
The number of turns in a conductor (copper) , the induced EMF is directly _______
proportional to the # of turns in the coil
The left hand rule determines the what?
the direction of the induced current
EMF is expressed in what?
volts
What are wavelengths measure in?
Angstroms
Anode cooling chart formula for single phase
kvp x ma x time
Anode cooling chart formula for 3 phase / high frequency
kvp x ma x time x 1.40
Laying in the prone position the barium will be where ?
barium in body of stomach
laying supine , barium will be where ?
in the fundus
peristalis occures best in what position
RAO
which flexure is lower?
right
area with more cancers?
sigmoid
what helps with peristalis in colon?
haustra
creatine and bun levels
creatine .6 to 1.5 BUN 10-20
upper poles of the kidney are more__
posterior
lower poles of kidney are more __
anterior
