basic concept part 2 Flashcards
1
Q
TWO BASIC TYPES OF RADIATION
A
Ø ELECTROMAGNETIC RADIATION
Ø PARTICULATE RADIATION
2
Q
TYPES OF ELECTROMAGNETIC RADIATION
A
¡ RADIO WAVES
¡ MICROWAVES
¡ INFRARED
¡ VISIBLE LIGHT
¡ ULTRAVIOLET LIGHT
¡ X-RAYS
¡ GAMMA RAYS
3
Q
The range of wavelengths of frequencies over which
electromagnetic radiation extends
A
ELECTROMAGNETIC SPECTRUM
4
Q
Have the longest wavelength in
the electromagnetic spectrum
A
radio waves
5
Q
Carry signals for television and
cellular phones
A
radio waves
6
Q
Basis for all non-written
communication and most wireless
communication
A
radio waves
7
Q
Radio stations, for example, are
identified through their frequency
of transmission and are called
A
radiofrequency emissions or RF
emissions.
8
Q
Frequency vary according to
use
A
microwaves
9
Q
waves that heat our food in a
microwave oven
A
longer microwaves
10
Q
used in
remote sensing
A
shorter microwaves
11
Q
Lies between the visible and
microwave portions of the
spectrum
A
infrared
12
Q
Wavelength of ____is just a
bit longer than that of red rays
Primary source: heat or thermal
radiation
A
infrared
13
Q
Heats any substance on which it
shines
Maybe considered radiant heat
A
infrared
14
Q
3 categories of infrared
A
¡ Near-infrared
¡ Far-infrared
¡ Mid-infrared
15
Q
closest to visible light
A
near-infrared
16
Q
closest to microwaves
A
far-infrared
17
Q
region between near and far infrared
A
mid-infrared
18
Q
The only EM waves visible to
human eyes
Seen as the colors of the
rainbow
A
visible light
19
Q
has the longest wavelength
A
red
20
Q
has the shortest
wavelength
A
violet
21
Q
When all the waves are seen together, they make
A
WHITE LIGHT
22
Q
Although photons of visible light travel in a straight line, their
course can deviate when they pass from one transparent medium
to another. The deviation in the line of travel is called
A
refraction
23
Q
Source: the Sun
A
uv
24
Q
most harmful and are almost
completely absorbed by our
atmospher
A
UV-C
25
harmful rays that cause
sunburn
UV-B
26
cause burning of the eye
surface (snow blindness or
photokeratitis)
UV-A
27
Has shorter wavelength than visible light
uv
28
closest to visible light or optical light
NUV
29
lies between NUV and EUV; ionizing
radiation completely absorbed by ozone
FUV
30
closest to x-rays and the most energetic
of the 3 regions; ionizing radiation observed by the
atmosphere
EUV
31
Has shorter wavelengths and higher energy than uv waves
x-rays
32
First observed and documented in
1895 by Wilhelm Conrad Roentgen
X-rays
33
Relatively harmful to the human body, but in controlled doses, can be used
for medical purposes such as imaging the internal structures of the human
body
x-rays
34
Have the smallest wavelength and the
most energy of any other wave in the
EM spectrum
gamma rays
35
Generated by radioactive atoms and in
nuclear explosions
gamma rays
36
Can kill living cells which medicine uses
to its advantage, using gamma rays to
kill cancerous cells
gamma rays
37
the viewing conditions of a radiographic or fluoroscopic
image are critical to diagnosis; described by wavelength
visible light
38
described in terms of energy
X and gamma radiation
39
fundamental to producing a high quality radiograph
xray
40
used in Nuclear Medicine
gamma
41
has become more important in medical imaging with the introduction of MRI; described by frequency
RF
42
The only difference between x-rays and gamma rays is their
origin
43
are emitted from the electron cloud of an atom, or outside the nucleus
xray
44
are emitted spontaneously from radioactive
material, inside the nucleus
gamma rays
45
Stream of atomic or subatomic particles that may be positively charged or negatively charged or not at all
particulate radiation
46
Atomic or subatomic particles which carry energy in the form of kinetic energy or mass IN MOTION.
At rest, they cannot cause ionization
PARTICULATE RADIATION
47
Also known as corpuscular radiation
particulate radiation
48
Involves tiny fast-moving particles that have both energy and mass
particulate radiation
49
Primarily produced by disintegration of an unstable atom
particulate radiation
50
Type of ionizing radiation ejected by the nuclei of some unstable atom
alpha particles
51
Relatively heavy, high-energy subatomic particle
equivalent to a helium nucleus consisting of 2 protons and 2 neutrons
alpha particles
52
Discovered by Ernest Rutherford in 1899
alpha particles
53
Has mass of approximately 4
amu and carries 2 units of
positive electric charge
alpha particles
54
Emitted only from the nuclei
of heavy elements (high
atomic numbers)
alpha particles
55
¡ Average alpha particle: 4-7 MeV of
KE
¡ Ionizes approximately 40,000 atoms for every centimeter of travel through air
¡ Because of this amount of
ionization, the energy of the
alpha particles
56
Very short range in matter
¡ In air, it can travel
approximately 5 cm
¡ In soft tissue, range may be
less than 100 um
alpha particles
57
___ from an
external source is nearly
harmless because radiation
energy is deposited in the
superficial layer
¡ If deposited in the body, it
can intensely irradiate the
local tissue
alpha particles
58
uses alpha emitters
alpha particles
59
may be used to treat cancer
radium-226
60
serves as a static eliminator in paper mills
and other industries
Polonium-210
61
smoke detectors
Americium-241
62
High velocity electrons with an
electrical charge of -1
beta particles
63
beta means
high speed
64
Light particles with atomic mass number of
0
¡ Carry one unit of negative or positive
charge
beta particles
65
credited with the
discovery of beta particles
Henri Becquerel
66
In 1900, he showed that beta particles were
identical to electrons.
Henri Becquerel
67
originates in the nuclei of
radioactive atoms
Negative beta particles
68
It is their excess energy, in the form of
speed, that causes harm to living cells
beta particles
69
treatment of thyroid disorders (cancer, Grave’s
disease)
Iodine-131
70
radioactive tracer in medical and agricultural
studies; in a controlled manner, used to treat bone tumors
Strontium-90
71
life science and drug metabolism studies
tritium
72
Positive beta particles
positron
73
the antiparticle or the
antimatter counterpart of the electron
Positron or anti-electron
74
Has the same mass as an electron and an electric charge
of +1e
positron
75
When a low-energy positron collides with a low-energy electron, annihilation occurs resulting in two or more gamma ray photons
Electron-Positron Annihilation
76
concluded the
existence of a positive particle of
electronic mass (positive electron) and was
awarded the Nobel Prize in Physics in 1936
1932 – Carl D. Anderson
77
the production
of positive electrons by means of
radioactive sources and the identification
of Anderson’s particle with the anti-
electron, whose existence had been
suggested by
Paul Adrien Maurice Dirac
78
¡ Are able to penetrate tissues and organs of the human body when the radiation source is outside the body
¡ can also be hazardous if neutron-
emitting nuclear substances are deposited inside the body
¡ High-speed nuclear particles that have an ability to penetrate other materials
neutrons
79
A free neutron has a half-life of approximately
15 mins
80
the neutron decays via _____ to a proton and an
antineutrino
beta decay
81
energies below thermal energies typically
corresponding to meV and sub meV energies (0 to 0.025
eV)
cold neutrons
82
neutrons colliding with atomic nuclei
either pick up energy if they are moving slower than the
colliding nucleus, or lose energy if they are moving
faster
thermal neutrons
83
generally have energies between 100’s of
eV to 0.5 or 1 MeV
slow neutron
84
generally between 0.5 and 10-20 MeV.
These are the energies of neutrons emitted by fission
sources
fast neutrons
85
above 20 MeV
high energy neutrons
86
primarily occurs inside a nuclear reactor
Neutron radiation
87
exist independently and free of any
nucleons; they are unstable outside the nucleus
free neutrons
88
TYPES OF RADIATION ACCORDING TO ITS
IONIZING ABILITY
Ø IONIZING RADIATION
Ø NON-IONIZING RADIATION
89
Refers to any process by which
electrically neutral atoms or molecules
are converted to electrically charged
atoms or molecules (ions)
ionization
90
Radiation that has enough energy to cause the atoms in a molecule to vibrate but
not enough to remove electrons
NON-IONIZING RADIATION
91
the energy is converted to heat which can lead to burns, depending on time exposure and energy concentration
NON-IONIZING RADIATION
92
¡ Extremely low-frequency radiation
¡ Has very long wave lengths
¡ Frequencies in the range of 100 Hz or less
¡ UV radiation (except the high energy end of the UV-
spectrum), visible light, infrared radiation, microwaves,
and radio waves
NON-IONIZING RADIATION
93
Carried by any of several types of
particles and rays given off by
radioactive material, X-ray
machines, and nuclear reactions
IONIZING RADIATION
94
Radiation with enough energy so
that during an interaction with an
atom, it can remove tightly bound
electrons from the orbit of an atom,
causing the atom to become
charged or ionized
IONIZING RADIATION
95
¡ Includes alpha particles, beta particles, gamma rays,
and X-rays
¡ Types: Directly Ionizing and Indirectly Ionizing
ionizing radiation
96
Includes charged particles
(electrons, positrons,
protons, alpha particles,
heavy ions) with sufficient
energy to ionize atoms or
molecules
DIRECTLY IONIZING RADIATION
97
All directly ionizing
radiation must be moving
at relativistic speeds in
order to carry the required
kinetic energy
DIRECTLY IONIZING RADIATION
98
¡ When charged particles
pass through materials they
ionize atoms
¡ Involves a larger energy
transfer event from the
primary charged particle to
an electron of the medium
DIRECTLY IONIZING RADIATION
99
This may result in the production of a relatively
energetic secondary electron, often referred to
as a ______ which itself will go on to
produce multiple ionization events
delta ray
100
very fast electrons produced in quantity by
alpha particles or other fast energetic charged
particles knocking orbiting electrons out of atoms.
Collectively, these electrons are defined as delta
radiation when they have sufficient energy to ionize
further atoms through subsequent interactions on
their own
delta ray
101
tends to deposit its
energy at localized range in materials
Directly ionizing radiation
102
deposits it along its whole path
ionizing radiation
