Radiation Flashcards
The emission of energy as electromagnetic waves or as moving subatomic particles, especially high-energy particles which cause ionization.
Radiation
A stream of particles or electromagnetic waves emitted by the atoms and molecules of a radioactive substance as a result of nuclear decay.
Radiation
is the process by which ions are formed by gain or loss of an electron from an atom or molecule.
IONIZATION
MEANS OF RADIATION ENTRY THROUGH THE BODY (3)
- Inhalation
2.Ingestion
3.Absorption/ skin
cuts
Radiation coming from outside the body
External exposure
Radiation emitted within the body
Internal exposure
Sources of radiation
- Natural sources
- Man-made radiation sources
constant source of ionizing radiation present in the environment and emitted from a variety of sources.
NATURAL SOURCES
Natural sources also called as
Background radiation
A source of natural background radiation, which originates in outer space and is composed of penetrating ionizing radiation (both particulate and electromagnetic).
COSMIC BACKGROUND RADIATION
The sun and stars send a constant stream of cosmic radiation to Earth, much like a steady drizzle of rain.
COSMIC BACKGROUND RADIATION
Electromagnetic radiation emitted by the Earth’s surface and atmosphere is called terrestrial or long wave radiation (Arnfield 2020)
terrestrial radiation
Low levels of terrestrial radiation
Uranium, Thorium, and their decay products are found everywhere.
decay products of uranium
Throrium, Radium, and Radon
The major isotopes of concern for terrestrial radiation are
Uranium and the decay products of uranium
is a naturally occurring radioactive gas which can accumulate in enclosed places, including houses and other buildings.
Radon
When a radioactive atom decays, its nucleus, which is unstable, breaks down, turning into the nucleus of another element called a
daughter product.
It comes from the radioactive decay chain of uranium, which is present in small amounts almost everywhere in the Earth’s crust
Radon
3 natural sources
cosmic
and terrestrial sources
INTERNAL RADIONUCLIDE (RADIATION)
It is the primary source of radiation from the human body.
potassium-40
K40 in a 70-kg person is
about 5,000 Bq, which represents 5,000 atoms
essentially are from human food derived from plants.
Carbon-14
The rates of disintegration of—and— in the normal adult body are comparable (a few thousand disintegrated nuclei per second).
Potassium-40
Carbon-14
TWO DISTINCT GROUPS EXPOSED TO MAN-MADE RADIATION SOURCES
- Members of the public 2.Occupationally exposed
individuals
is any individual except when that individual is receiving an occupational dose.
members of the public
The most significant source of man-made radiation exposure to the public is from medical procedures, such as (3)
diagnostic x- rays, nuclear medicine, and radiation therapy.
Is the dose received by an individual in the course of employment in which the individual’s assigned duties involves exposure to radiation or to radioactive material.
occupationally exposed individuals
Occupationally exposed individuals, however, are monitored for radiation exposure with ____ so that their exposures are well documented in comparison to the doses received by members of the public
dosimeters
Two basic types of radiation
Electromagnetic radiation
Electromagnetic waves
Pure energy with no mass and is like vibrating or pulsating waves of electrical and magnetic energy.
Electromagnetic radiation
is produced by vibrating electric charge and as such, they consist of both an electric and magnetic component.
Electromagnetic radiation
Electromagnetic waves Act like a stream of small “packets” of energy called
photons
Travel in a wave-like pattern
Electromagnetic radiation
Travel in a wave-like pattern
Electromagnetic radiation
Electromagnetic radiation travels in a straight line at the speed of
speed of light (3x10^8m/s)
A changing magnetic field will induce a changing electric field and vice-versa (the two are linked)
These changing fields form
Electromagnetic waves
do not require a medium to propagate.
Electromagnetic waves
The electromagnetic energy can be described by
frequency, wavelength, or energy
The number of crests that pass a given point within one second is described as the
frequency of the wave.
The unit of frequency is
Hertz (Hz)
The unit of frequency is Hertz (Hz), named after?
established the existence of radio waves.
Heinrich Hertz
One wave or cycle per second is called a
Hertz (Hz)
Wavelength is represented by the Greek letter
lambda (λ)
The distance between the crests is the
wavelength.
The ____ the wavelength, lower frequency
longer
The_____ the wavelength, higher the frequency
shorter
An electromagnetic wave can also be described in terms of its
Energy
An electromagnetic wave can also be described in terms of its
Energy
The unit of energy is called_____ or Joule (J).
electron volts (eV)
is the amount of kinetic energy needed to move an electron through one volt potential.
An electron volt
The _____ the wavelength, higher the frequency, the higher the energy of electromagnetic radiation
shorter
The____ the wavelength, lower frequency, the lower the energy of electromagnetic radiation
longer
Wavelength and frequency are ____ related to each other
Inversely
