21 terms

# Radiation Physics Chapters 7 & 12

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In a characteristic interaction, an x-ray photon results when:
An outer shell electron fills a hole left by an ejected inner shell electron
When a ______________________ occurs, the incident electron interacts with the force field of the nucleus:
Bremsstrahlung Interaction
The energy of a characteristic photon depends on the:
Difference of binding energies of the two shells involved
In a bremsstrahlung interaction, the emission of a photon is caused by:
The deceleration of the electron as it nears the nucleus
It is necessary for the incident electron to have higher energy than the K-shell electrons in order for this interaction to occur:
Characteristic
The principle difference between an x-ray photon and a gamma ray is the:
Origin of the photon
The energy of the photons produced in bremsstrahlung x-ray production is dependent on:
Incident electron speed
Atomic # of target
Electron to nucleus distance
Approximate percentage of electron energy that is converted to x-ray energy in the x-ray tube?
1%
Approximate percentage of Kenetic Energy converted into thermal energy 'heat'?
99%
Explain the difference between keV and kVp
keV: Unit of measure of binding energy of an electron
Kvp: controls the quality of electrons striking the target
keV
1,000 electron volts
What effect does increasing the mAs have on the total x-ray emission spectrum?
Changes in Amplitude
What effect does increasing the kVp have on the total x-ray emission spectrum?
Changes the Amplitude and the Number of Photons
X-rays are produced when a high-speed electron from the _____ hits the _____ target.
Cathode / Anode
An Incident Electron travels from zero to half the speed of light in:
2 cm
Higher Mass or Speed of the Incident Electron =
Higher quality & quantity of Photons produced.
Two types of Target Interactions:
Heat & X-ray production
The production of X-ray is very ________.
Inefficient
In _______ the majority of energy is converted into radiation instead of heat.
Therapy
Two types of target interactions that cause radiation:
Bremsstrahlung / Characteristic
Graph of X-ray energies
Spectrum