Radiation Quantities and Units Flashcards
Used to describe a beam of radiation
Radiation Quantities
Radiation fall into two general categories:
Radiation Exposure
Radiation Dose
Radiation travelling through air
Total radiation delivered to a body
Radiation Exposure
Radiation travelling through a medium
Concentration of radiation at some point or to a specific tissue or organ
Radiation Dose
a measure of the amount of radiation, and therefore measures a radiation beam.
Radiation quantities
Radiation quantities can be categorized into 2:
Radiation exposure and radiation dose
which is a measure of the radiation that emanates from the source and delivered to a specific target. It is therefore usually measured in
air
Radiation exposure
which is a measure of the concentration of radiation at a given point in matter.
Radiation dose
It is a measure of the amount of radiation when the radiation interacts in a medium.
Radiation dose
The removal of an orbital electron from an atom.
Ionization
Produces an ion pair
Negatively charged electron and Positively charged ion (atom minus 1 electron)
causes the deposition of energy to the interacting medium.
The removal of electron from an atom
usually transferred to the ejected electron, and will eventually be absorb by the medium as the recoil electron undergoes a series of interaction and eventually come to rest.
the energy of the incident radiation
A form of radiation with sufficient energy to excite and or ionize atoms.
Ionizing Radiation
Ionizing radiation particles
•Gamma rays,
X-rays,
heavy charged particles,
•neutrons,
and beta particles are examples of ionizing radiation.
Not all radiation are capable of ionization. Radiations that are capable of ionization are also called
Ionizing radiation
the electromagnetic radiation, high frequency ultraviolet radiation, x-rays and gamma rays are
ionizing radiation
Ionizing radiation is divided into two categories:
Directly Ionizing and Indirectly Ionizing
Directly ionizing
Alpha and beta
Indirectly Ionizing
photons and neutrons
includes all charged particles.
These particles interact with electrons through long-range Coulombic charged-particle interactions and deliver energy to matter directly.
Directly ionizing radiation
•includes x-rays, gamma rays, and all uncharged particles. They will typically interact via a transfer of energy to a single charged particle, and it is the secondary charged particle that delivers energy to the absorbing material.
Indirectly ionizing radiation
unit of exposure
x
unit of absorbed dose
D
Unit of equivalent dose
H
Unit of Activity
A
It is the measure of ionization produced in air by photons.
Exposure
It is a quantity of charge released during the ionization of air by passage of radiation under strictly defined conditions.
Exposure
the measure of radiation that emanates from the source.
Exposure
measured using ionization chamber.
Exposure
Exposure is divided into two:
Primary standard instrument
Secondary instrument
Free air ionization chamber
Primary standard instrument
Instruments designed for field use such as the Victoreen R meter.
Secondary instrument
therefore created to produce the conditions necessary to measure radiation exposure. It is through the use of ionization chamber.
Device
It is the instrument employed in the measurement of the exposure according to the definition of Roentgen (old unit of exposure).
Free Air Ionization Chamber
the quantity of charge released during the ionization of air by passage of radiation under strictly defined conditions.
Roentgen
It is generally used for calibration of secondary instruments designed for field use.
Free Air Ionization Chamber
It is confined to some national standards laboratories.
Free Air Ionization Chamber
the primary instrument, and is constructed based on the definition of Roentgen, which is the old unit of measure of exposure.
Free air ionization chamber
