Lecture 1 Flashcards
Matter
Anything that occupies space and has mass.
Energy
The ability to do work.
Atoms
All matter is composed of fundamental building blocks which are arranged in various complex ways
Mass
A primary distinguishing characteristic of matter.
the quantity of matter contained in any physical object
Forms of energy
-Solar
-Mechanical
-Radiation
-Sound
-Chemical
Potential energy
Ability to do work by virtue of position
ex: roller coaster or stretch spring
Kinetic energy
Energy of motion, work because of motion
ex: moving car or moving river
Chemical energy
Energy released by chemical reaction
ex: energy from the food we eat
Electrical energy
Electrons moving through an electrical potential difference
ex: household electricity – 110 volts
Thermal energy
Energy of motion at the atomic and molecular level. The kinetic energy of molecules vibrating.
ex: solar energy to heat water
Nuclear energy
Energy contained in the nucleus of an atom
ex: nuclear electric power plants
Electromagnetic energy
Radiation is the transfer of energy (usually
through space); often referred to Electromagnetic radiation when it is traveling through space
Exposed or Irradiated
Matter that intercepts radiation and absorbs part or all of it is exposed or irradiated
Ionizing radiation
is radiation with enough energy so that during an interaction with an atom, it can remove tightly bound electrons from their orbits, causing the atom to become charged or ionized (examples: gamma rays, neutrons)
Non-ionizing radiation
is radiation without enough energy to separate molecules or remove electrons from atoms. Examples are visible light, radio, television waves, ultra violet (UV), and microwaves with a large spectrum of energies
Sound energy
is a kinetic (mechanical) energy caused by the physical vibration of air particles or molecules that moves through substances
Radioactivity
is the spontaneous transformation of an unstable atom and often results in the emission of radiation. This process is referred to as a transformation, a decay or
a disintegrations of an atom
Radioactive Material
is any material that contains radioactive atoms
Radioactive Contamination
is radioactive material distributed over some area, equipment or person
MRI Signal Production
-Images are created by interaction of a magnetic field and radiowaves with tissue
-Atoms – Nucleus – Electrons
-Non-Ionizing Radiation
Sonography
Uses a mechanical wave to
generate the image
Non-ionizing
X-ray energy is used to expose
or irradiate patients for
medical treatments or
diagnosis
Ionizing radiation occurs in two forms
wave and particle
Particle radiation
-Alpha
-Beta
-Neutron
Waves radiation
-Gamma Rays
-X-Rays
Alpha
An alpha is a particle emitted from the nucleus of an atom, that contains 2 protons and 2 neutrons.
It is identical to the nucleus of a Helium atom, without the electrons
Beta
A beta is a high speed particle, identical to an electron, that is emitted from the nucleus of an atom
Neutron
Neutrons are neutral particles that are normally contained in the nucleus of all atoms and may be removed by various interactions or processes like collision and fission
Gamma Rays
Gamma rays are electromagnetic waves / photons emitted from the nucleus (center) of an atom
X-Rays
X- Rays are electromagnetic waves / photons emitted not from the nucleus, but normally emitted by energy changes in electrons. These energy changes are either in electron orbital shells that surround an atom or in the process of slowing down electrons, such as in an X-ray machine.
Alpha Decay
a radioactive process in which a particle with two neutrons and two protons is ejected from the nucleus of a radioactive atom
-Alpha decay only occurs in very heavy elements such as uranium, thorium and radium
Beta decay
a radioactive process in which an electron is emitted from the nucleus of a radioactive atom, along with an unusual particle called an antineutrino (almost massless particle that
carries away some of the energy)
Neutron radiation
a form of ionizing radiation that presents a free neutrons. Typical phenomena are nuclear fission or nuclear fusion causing the release of free neutrons, which then react with nuclei of other atoms to form new isotopes—which, in turn, may trigger further neutron radiation
Crookes tube
-large partially evacuated glass tubes
-the beginning of the modern fluorescent
lamps and x-ray tubes
Many university physics labs were
investigating the conduction of cathode
rays… electrons
in 1870s & 1880s
Birth of X-Ray
November 8, 1895: Wilhelm Conrad Rontgen discovered x-rays
-Honored in 1901 with the first Nobel prize in physics for his efforts
First Radiograph
Anna Bertha Roentgen, 15 min exposure
Gray (Gy)
-to measure absorbed dose … the amount of energy actually absorbed in some material, and is used for any type of radiation and any material (doesn’t describe the biological effects of the different radiations)
Gy = J / kg (one joule of energy deposited in one kg of a material)
Sievert (Sv)
to derive equivalent dose … the absorbed dose in human tissue to the effective biological damage of the radiation
Sv = Gy x Q (Q = quality factor unique to the type of incident radiation)
Becquerel (Bq)
to measure a radioactivity … the quantity of a radioactive material that have 1 transformations /1s
Bq = one transformation per second, there are 3.7 x 1010 Bq in one curie
Roentgen (R)
to measure exposure but only to describe for gamma and X-rays, and only in air.
R = depositing in dry air enough energy to cause 2.58E-4 coulombs per kg
Air kerma = depositing in dry air, exposure in air
Curie (Ci)
to measure radioactivity. One curie is that quantity of a radioactive material that will
have 37,000,000,000 transformations in one second. 3.7 x 1010 Bq
