Radiation Physics Flashcards
2 parts of an atom
Orbiting electron and nucleus
Contains equal number of protons and electrons
Neutral atom
Dense core of the atom
Nucleus
Nucleus is composed of
Neutrons and protons
Number of protons and neutron determines the ?
Mass number or atomic weight
Number of protons equals the number of electrons determines the?
Atomic number
Tiny, negatively charged particles that have very little mass
Electrons
Electrons travel around the nucleus in well defined paths known?
Orbits/shell
Binding energy or binding force of an electron ( maintains electrons in their orbits)
Electrostatic force
Electrostatic force is measured by ?
Electron-volts (eV) or kilo-electron volts (keV)
Two or more atoms joined by chemical bonds
Molecules
Formed by transfer of electrons or by sharing of electrons between the outermost shells of atom
Molecules
When matter is altered, the result is?
Energy
An atom that gains or loses an electron
Ions
Process of converting atom into ions
Ionization
It requires sufficient energy to overcome the electrostatic force that binds the electron to the nucleus
Ionization
Electron is removed from an atom wherein the atom become the positive ion and the ejected ion becomes the negative ion
Ion pair
Emission and propagation of energy through space or a substance in the form of waves or particles
Radiation
Process by which certain unstable atoms or elements undergo spontaneous disintegration or decay in an effort to attain a more balance nuclear state
Radioactivity
Gives off energy in the form of particles or Rays as a result of the disintegration of the atomic nuclei
Radioactive substance
Radiation capable of producing ions by removing or adding an electron to an Atom
Ionizing radiation
2 types of ionizing radiation
Particulate radiation and electromagnetic radiation
Tiny particles of matter that possess mass and travel in straight line at high speeds
Particulate radiation
Transmit kinetic energy by means of their extremely fast-moving, small masses
Particulate radiation
Types of particulate radiation
Electrons. Alpha particles, protons , neutrons
Movement of energy through space as a combination of electric and magnetic fields
Electromagnetic radiation
Energy propagated is accompanied by oscillating electric and magnetic fields positioned at right angles to one another
Electromagnetic radiation
Move through space as both a particle and a wave
Electromagnetic radiation
2 concept of electromagnetic radiation
Particulate concept and wave concept
Concept where electromagnetic radiation are discrete bundles of energy called photons or quanta
Particle concept
Bundles of energy with no mass or weight that travel as waves at the speed of light and move through space in straight line
Photons or quanta
Concept where electromagnetic radiation are propagated in the form of waves with properties of velocity,wavelength and frequency
Wave concept
Speed of the wave or speed of light (186,000 miles per second)
Velocity
Distance between the crest of one wave to the crest of the next wave
Wavelength
Determines the energy and penetrating power of radiation
Wavelength (shorter the distance, the higher the energy and ability to penetrate)
Number of wavelengths that pass a given point in certain amount of time
Frequency ( high frequency=shorter wavelengths ;and vice versa )
High energy, ionizing electromagnetic radiation
X-radiation
Weightless bundles of energy without an electrical charge that travel in waves with specific frequency at the speed of light
X-Rays
TRUE or FALSE
X-Ray photons interact with materials and cause ionization
True
TRUE or FALSE
X-rays cannot be focused to a point and always diverge from a point
True
TRUE or FALSE
X-rays are sometimes absorbed by matter
False ( always)
TRUE or FALSE
X-rays can cause all substances to fluoresce or emit radiation In longer wavelength
False (certain substance only)
Allows for movement and positioning of the tube head
Extension arm
Tightly seal, heavy metal housing that contains the X-ray tube
X-ray tube head
Protects the X-ray tube and grounds the high voltage component
Metal housing
Prevents overheating by absorbing the heat created by the production of X-rays
Insulating oil
Acts as a filter to the X-ray beam
Tube head seal
Device that alters the voltage of incoming electricity
Transformer
Filter out the non penetrating, longer wavelength X-rays
Aluminum disks (0.5 mm thick of aluminum)
How many volts does filament circuit uses
3-5 volts
Lead plate with central hole that fits directly over the opening of the metal housing where the X-ray exit
Lead collimator
Restricts and reshapes the size of the X-ray beam
Lead collimator
Aims and shales the X-ray beam
Position indicating device
Heart of the X-ray generating system
X-ray tube
Leaded glass vacuum tube that prevents X-rays from escaping in all direction and with a window to permit the X-ray beam to exit the tube
Leaded glass housing
Supplies the electrons necessary to generate X-ray (X-ray produced are accelerated toward the anode)
Cathode
2 components of cathode
Tungsten filament and molybdenum cup
2 electrical circuits used in X-ray production
Filament circuit and high voltage circuit
Focuses the electrons into a narrow beam and directs the beam across the tube toward the tungsten target of the anode
Molybdenum cup
Converts electrons into X-ray photons
Anode
Produces the electrons when heated
Tungsten filament
2 component of anode
Tungsten target and copper stem
Dissipated the heat away from the tungsten target
Copper stem
Energy used to make X-rays
Electricity
Flow of electrons through a conductor
Electrical current
Measurement of the number of electrons moving through a conductor
Amperage or milliamperage
Measurement of electrical force that caused electrons to move from a negative pole to a positive one
Voltage
Located on the control panel, increases or decreases the number of electrons passing through the cathode filament
Milliamperage adjustment
Regulates the flow of the electrical current to the filament of the X-ray tube (controlled by milliampere settings)
Filament circuit
Controls the current passing from cathode to the anode
Kilovoltage peak adjustment
How many volts does the high voltage circuit uses ?
65,000 - 100,000 volts
Provides the high voltage to accelerate electrons and generate X-rays in the X-ray tube (controlled by kilovoltage settings)
High voltage circuit
Device used to either increase or decrease the voltage and the electrical circuit
Transformers
3 types of transformers
> step down transformer
step up transformer
autotransformer
Used to decrease the voltage from the incoming 110-220 line voltage to 3-5 volts
Step down transformer
Used to increase the voltage from 110-220 line voltage to 65,000 to 100,000 volts
Step up transformer
Serves as a voltage compensator that corrects minor fluctuations in the current
Autotransformer
Types of X-ray produced
> general radiation/bremsstrahlung/ braking radiation
>characteristic radiation
Primary source of X-ray photons from an X-ray tube, produces by sudden stopping or slowing of high speed electrons
General/braking radiation or bremsstrahlung
Electron from the filament displaces an electron from the shell of tungsten atom and causes ionization of the atom (this is produced only at 70 kilovoltage peak equivalent to binding energy of k shell electron
Characteristic radiation
3 types of x-radiation definitions
Primary, secondary and scatter radiation
Penetrating X-ray beam that is produced at the target of the anode and exits the tube head (useful beam)
Primary radiation
This is created when the primary radiation interacts with matter
Secondary radiation
A result of an X-ray that has been deflected from its path by the interaction of matter
Scatter radiation
X-ray photon collides with a tightly bound, inner shell electron and ejects it
Photoelectric effect (accounts for 30% of interactions of matter)
Ejected electron absorbed by the other atom
Photoelectron
2 types of scatter radiation
> Compton scatter
> coherent/classical/elastic/Thompson scattering
X-ray photon collides with a loosely bound outer shell electron and gives up part of its energy to eject the electron from the orbit (X-ray photon loses energy and continues in a different direction)
Compton scatter (52% of interactions of matter)
X-ray photon path is altered by matter , this occurs when a low energy photon interacts with outer shell electron (no change in atom and no ionization occurs)
Coherent scatter (8% of interactions)
Interval of time during which the X-rays are produced (measured in impulses)
Exposure time ( 60 impulses = 1 second)
Regulates the temperature of cathode filament
Tube current /milliamperage ( increase in milliamperage, increases the number of electrons produced)
TRUE or FALSE
If milliamperage is increased, there must be decrease in exposure time
True
TRUE or FALSE
Increasing the tube voltage,will decrease the penetrating ability of the X-ray beam (kvp)
False (will increase penetrating ability)
This removes low frequency radiation
Filtration
Used to reduce the size of the X-ray beam, and reduces the exposure area
Collimation
TRUE or FALSE
Intensity of the beam is inversely proportional to the square of the distance from the source
True
TRUE or FALSE
X-ray beam spreads out as it moves from the source
True
TRUE or FALSE
The thickness of an absorber required to reduce one half the number of X-ray photon passing through it
True
Increase the mean penetrating capability of X-ray beam while reducing the intensity
Aluminum filters
Path of electrical current
Circuit
TRUE or FALSE
X-rays travel in straight line and cannot be deflected or scattered
FALSE (can be deflected and scattered)
Anything that occupies space and has a mass
Matter
Serves as the focal spot and converts bombarding electrons into X-ray photons
Tungsten target
Permits the exit of X-rays to the tube head
Tube head seal
Fundamental unit of matter
Atom
