Radiation Physics Flashcards
what kind of Effect is Radiation induced cancer
Stochastic effect
how strong of a carcinogen is Radiation
weak carcinogen (20x less than smoking)
what electron shell has the highest binding energy
The K shell (the inner most)
what is the atomic number
Number of protons
what is the atomic mass
Number of protons and neutrons
High Z number(protons) does what to the binding energy
increases the binding energy
does Radiation energy move
Yes
How can Radiation move through space
Electromagnetic waves
Energentic particlesParticulate
is all radiation ionizing
No
why might not all radiation be ionizing
Needs sufficient energy to remove electrons from atoms it encounters in its path
the process of removing electrons from atoms
Ionization
How are Electric and MAgnetic planes rotated in relation to one another
Planes at right angles
how fast does Electromagnetic radiation go
Speed of light
what is an angstrom
1Angstrom=10^-10meters
what is the velocity of EMRs in air
all are the same
what is the definition of electromagnetic radiation
Transfer of energy through space as a combo of electrical and magnetic fields
what is Quantum theory
Electromagnetic radiation is considered as bundles of energy called photons
Energy of a wave
E=hv
relation of energy and freqeuncy
Direct
Relation of energy and wavelength
Inverse
what is ionization
Gaining of loosing an electon
when does Ionization occur
When particulate or electromagnetic radiation energy is greater than binding energy
what is the threshold for ionization
10eV
what types of EMR is ionization radiation
Gamma rays
X rays
UV rays (only the highest energy ones though)
what is an ion pair
The combo of the ejected negative ion and the remainder atom which is positive
when are Gamma rays used
To image the distribution of radiopharmaceuticals
when are X-rays used
Diagnostic imaging
When is visible light used
Extra oral imaging and viewing radiographs
when are Radiofrequency waves used
MRI
how much do X rays weight
No weight
Charge of X rays
No charge
How do x rays travel
In waves with a specific frequency at the speed of light
How do X rays leave the central focus
Diverging in a straight line
wavelenthgs of X rays
.1-.5Angustrum
what can X rays do
cause Fluorescence
Affect photographic film
Produce biological and chemical changes
how are X rays produced
High velocity electrons are suddenly decelerated when they pass close to the nuclei of high Z absorbing materials
The requirments of X ray products
Electrons
High velocity to those elctrons
High Z number material (tungsten)
2 types of X ray production
Bremsstrahlung radiation
Characteristic radition
how does Bremsstrahlung radition work
Fast moving electrons slow/stop when close to the nucleus of atoms releaseing energy
how does Characteristic radiation occur
Few electrons interact with tungston electrons, and ionize the Inner shell electrons and energy is released when they fall down to the higher binding energy level
do all electrons move at the same velocity for Bremmstrahlung radiation
No(some move at higher and lower velocity)
Can electrons in Bremmstrahlung radition experience multiple declerations
Yes (if still traveling fast) leading to different wavelengths of light produced
what is the result of Bremmstrahlung radiation?
Polychromatic(heterogeneous) x ray beam
how much of the X ray beam is Bremsstrahlung
70%
what part of the X ray tube makes Bremsstrahlung radiation
Anode
what is the ultimate fate of an electron in Bremsstrahlung radition
It will slow down to a resting state and be absorbed by an atom needing an electron
what kid of X-ray beam does Characteristic radition give off
A Heterogeneous X ray beem with a narrower energy spectrum
how much of the X ray beem is Characteristic
30%`
What percentage of the energy released from forming Radiation is released actually as radition
1% (the rest is heat)
How to get Homogenous radiation
switching current to DC
why does DC current make Homogenous radition
Kilovoltage rapidly rises to its peak and remains there throughout the x-ray exposure, leading to cathode electrons with similar KE
how much radiation does Homogenous radiation deliver to a patiation
20% less
