Ionizing Radiation Flashcards
What is matter?
Anything that has mass and occupies a space
The _____ is the basic unit of all
matter
atom
What is in the nucleus of an atom?
Protons + Neutrons
What is the atomic mass (A)?
Number of protons + neutrons
What is the atomic number (Z)?
Number of protons
- determines identity of the atom
Protons and electrons are the same # in a _______ atom
neutral
What is the binding energy?
The amount of energy required to remove an electron from its shell.
What is binding energy measured in?
electron Volts (eV)
Within a given atom, inner shells electrons are _____ tightly bound
more
The more protons (higher atomic number) the electrons are ______ tightly bound
more
What is ionization?
Process of forming a positive and negative ion by removal of an electron from an neutral atom
If a neutral atom loses an electron becomes a ________ ion and the free
electron becomes a ________ ion.
positive
negative
What is radiation?
the transmission of energy through space (vacuum) and matter
What are the two forms/theories of radiation?
wave theory or quantum (particles) theory
Which radiation theory explains the propagation of radiation?
wave theory
Which radiation theory explains the interaction of radiation with matter?
quantum theory
Which theory concerns electromagnetic radiation?
wave theory
What is the distance between two successive crests?
wavelength
What is the number of wavelengths passing a particular point in time?
frequency
High energy radiation: _____ frequency, _____ wavelength
High frequency
short wavelength
Low energy radiation: ____ frequency, _____ wavelength
Low frequency
Long wavelength
What is the speed of radiation in wave theory?
speed of light
How are wavelength and frequency related in the wave theory of radiation?
inversely proportional
What is the definition of non-ionizing waves?
Does not have sufficient energy to eject an electron from the shells
What are examples of non-ionizing waves?
- radio waves
- microwaves
- infrared radiation
- visible light
- UV
What are examples of ionizing waves?
- x-rays
- gamma rays
- a little UV
What are the different types of waves?
What is quantum theory?
explains the interaction of radiation with matter
Quantum theory considers radiation as small discrete bundles of energy called…
photons
Each photon has…
- energy (eV)
- mass
- travels in straight lines at the speed of light
Quantum theory of radiation has particles that are usually charged besides…
neutrons and x-rays
What is energy in the wave theory equation?
Directly proportional to frequency, inversely proportional to wavelength.
High frequency means short wavelength → _____ energy
High
Low frequency means long wavelength → ____ energy
Low
What are other examples of particles/photons in the quantum theory of radiation?
alpha
beta+
beta-
electron
neutron
proton
Which photon has the most charge, most weight, and is very useful in cancer treatment?
alpha particle
What is linear energy transfer (LET)?
Rate of loss of energy from a particle as it moves through matter
What is best for creating an image: low LET or high LET?
low LET
What changes linear energy transfer (LET)?
Depends on velocity, charge and size
______ velocity
______ charge
_______ size
= greater LET
lower velocity
higher charge
bigger size
Higher linear energy transfer (LET) has _____ penetration
less
Why do higher LET have less penetration?
they lose their energy after short distances
What are x-rays? (according to wave theory)
They are weightless packages of pure energy (photons) without an electrical charge which travel in waves with a specific frequency and wavelength at the speed of light and are able to ionize matter.
What are the properties of x-rays?
- Invisible, weightless (depends on theory), no electric charge
- Travels in straight lines. (depends on theory)
- Travel at the speed of light
- Highly penetrating (short wavelengths = 0.01-0.1nm)
- Differentially absorbed by matter
- Can ionize matter
- Produce biological changes
X-rays travel in straight lines but in what direction?
X-ray beam diverges over distance
X-rays have a high or low LET
low LET
What is excitation?
When the transferred energy is not sufficient to overcome binding energy, electron is NOT ejected
What happens after an electron is excited but not ionized?
Instantaneously gives up this excess energy and returns to ground
level
The binding energy is:
a. The minimum energy required to remove an electron from its shell
b. The maximum energy required to remove an electron from its shell
c. The minimum energy required to remove a proton from the nucleus
d. The maximum energy required to remove a proton from the nucleus
a. The minimum energy required to remove an electron from its shell
Which of the following is false regarding the wave theory of x-radiation?
a. X-rays have a mass
b. Increased frequency means short wavelengths
c. X-rays travel at the speed of light in a vacuum
d. The waves are formed as a combination of electro and magnetic fields
a. X-rays have a mass
The higher the mass and charge, the higher the LET
– True
– False
– True
Microwaves are ionizing
– True
– False
False
Considering elements A and B. Is the following statement true or
false?
– To remove an electron from the K shell of element B requires more energy than element A.
Element A (atomic number 100)
Element B (atomic number 110)
True
