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Chapter 7 Physics

Chapter 7 Physics Xray Production
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Almost all of the kinetic energy of the incident electron is converted to?
Heat
What percentage of target interaction results in the production of xray photons?
1 percent
The transfer of incident electrons' kinetic energy to the outer-shell electrons causing vibration of the outer-shell electron results in the emission of?
Infrared radiation
The types of target interaction that occur in the production of xray photons in the diagnostic range are dependent upon?
Incident electron kinetic energy
The energy of a brem photon is?
The difference between the enetering and exiting kinetic energy of the incoming electron
Brem interactions may occur only when the incident electron interacts with?
The force field around the nucleus
Characteristic interactions may occur only when the incident electron interacts with?
An inner shell electron
During a characteristic interaction, the kinetic energy of the incident electron must be _______the electron it knocks from orbit.
Greater than that of
During a characteristic interaction, the dropping of a higher-energy state electron into a lower-energy state hole results in the emission of?
A photon of electromagnetic energy
The energy of a characteristic photon is?
The sum of the binding energy of the outer and inner shells between which the electron dropped
At the end of the characterstic cascade, the ______ shell is missing an electron.
Outermost
The K shell can hold a maximum number of ____electrons.
2
If the peak kVp is 110, the average keV energy of that beam would be?
33-44 keV (30-40%)
X rays are characterized as?
Both: electromagnetic waves of short wavelength and electromagnetic waves with high frequencies
The emission spectrum of an xray beam from a tungsten anode consists of?
All of the above:
A characterstic spike at 69 keV
A significant portion due to brem interactions
A mixture of brem and characteristic interactions
If uranium(92) were used to produce x-radiation, rather than tungsten?
All of the above:
The K shell binding energy would be greater than with tungsten
The intensity of brems production would be greater
The energy of characteristic photons would be greater than with tungsten
Electrons traveling from the cathode filament to the anode are called?
Primary electrons
When comparing the xray emission spectrum between beams produced at 70 kVp and 110 kVp?
The 70 kVp beam would demonstrate less brems and higher characteristic spike
For the element of molybdenum, the effective energy of characteristic interactions is?
18 keV
When the xray emission spectra between single and three phase generators are compared?
Three phase beams would have a higher average energy
What is the emission of infrared energy?
Kinetic energy
What is M to L transition in atomic number 74?
9.6 keV
What is energy exerted on electrons by the nucleus of the atom?
Binding energy
What results from electrons interacting with the nuclear force field?
Brem radiation
What is energy that has ionizing potential and no mass?
Electromagnetic energy
What is molybdenum's characteristic spike?
20 keV
What is the difference between xray and gamma rays?
Xray is man made, gamma is naturally occuring
At what speed do electrons strike the anode?
Half the speed of light
What are the electrons called that strike the anode?
Incident electrons
Kinetic energy of the incident photons is changed into?
Xray photons
What percent of target interactions result in the production of xray?
Less than 1 percent
99% of the incident electrons kinetic energy is converted to?
Heat
What happens to the efficiency of photon production as kinetic energy of the incident electron increases?
Increases
What are the two types of target interactions that occur in the diagnostic range?
Brem and characteristic
What are the determining factors of which interaction will occur?
Electron kinetic energy and binding energy
Why is tungesten used as a target material?
Atomic number, maximum number of similar shell binding energies
What does brem mean in german?
Slowing or breaking
A brem interaction occurs when the incident electron interacts with the?
Force field of the nucleus
The incident electron has enough energy to pass through the?
Orbital shells
The force field of brem interactions causes the incident electron to?
Slow down and change direction
The energy lost in a brem interactions is emitted as an?
Xray photon
The energy of the xray photon is equal to the difference between the?
Entering and exiting incident photon
What is the range of energies in Brem interactions?
From peak to no energy
When does a characteristic interaction occur?
With an inner shell electron
In a characteristic interaction, the electron from an outer shell to an inner shell cases an _____to be emitted.
Xray photon
A ________interaction is the energy difference between the binding energy of the outer and inner shellf of the electrons involved.
Characteristic
Can there be only one or multiple xray photons produced in a characteristic interaction?
Many
How many electons does Tungesten have?
74
What is the binding energy of the k shell electrons?
69.5 keV
What interaction will cause the highest energy xray photon?
L shell electron dropping into a K shell hole or a N shell electron dropping into a K shell hole
Is ionization result only from K shell interactions?
No
Do characteristic interactions resul in one energy level or many?
Many
Which electron transfer produces a diagnostic xray?
K shell
Which interaction is the most common in the diagnostic xray range?
Brem
When is characteristic radiation produced?
with kVp over 70
What is the percentage of Brem and chacteristic radiation when 80-100 kVp is used?
80-90 Brem, 10-20 characteristic
K shell emissions for a characteristic peak with the effecetive energy range of?
69 keV
What is the maximum possible energy of any photon?
Maximum kVp
The average photon energy is only about ______% of the kVp
30-40
When mAs is changed, what effect does it have on the emission spectrum?
Changes amplitude
When kVp is changed, what effect does it have on the emission spectrum?
Number of high energy and amplitude
When xray photons pass through a filter, what happens to the low energy xray photons?
Absorbed
What effect does the abosorbtion of xrays through a filter have on the intensity and the average photon energy?
Decreases the intensity and increases energy
What happens to the beam intensity and average photon energy when generator efficiency increases?
Increases both
What is a characteristic cascade?
The reaction of electrons dropping into the holes created during a characteristic interaction until there is only a hole in the outer shell
What effect does increasing mAs and kVp have on the total xray emission spectrum?
When mAs is changed, it results in the amplitude of the emission spectrum graph.
When kVp is changed, it results in a change in the number of higher-energy photons, as well as in the amplitude
What is a Brem interaction?
An incident electron interacts with the force field of a nucleus, causing the electron to slow down, thus diverting the electrons course. The electron loses energy and changes course.
What is a Characteristic interaction?
When the incident electron interacts with an inner-shell electron, knocking out the inner shell electron and continuing in a slightly different direction which creates a shole int he inner shell making the shell unstable.