Review Of Radiation Physics Flashcards
Mass of the particle when it is not moving
Rest Mass
Measure of how strongly the particle is attracted to an electrical field, and can either be positive or negative
Electric Charge
Spontaneous disintegration of atomic nuclei
Radioactivity
Process whereby an excited, unstable nucleus dropped into state of lower energy stability
Radioactivity
Standard unit of radioactivity
Curie
Measure of the number of disintegrations occurring one gram of radium per second
Curie
Time required to decay one-half of the initial number of atoms
Time required for the initial activity to decrease by one-half
Half-life
Emitted by materials found in nature that is naturally radioactive and unstable
Natural Radioactivity
Emitted by materials which is a product of nuclear reaction initiated by man
Artificial Radioactivity
Modes of Decay
Alpha Particle Emission
Beta Particle Emission
Gamma Emission
Emitted from the nucleus of an atom as unstable nuclei undergo decay
Gamma emission
Mainly dependent on the wavelength of radiation and therefore its energy
Dependent on the density, thickness and atomic number of interacting material
Radiation interaction
Incident electron loses a small amount of energy to the nucleus of atom and bounce away with reduced energy
Elastic collision
High energy electron pass close to the nucleus and be strongly attracted that they will slow down and change direction losing some of their kinetic energy
Inelastic collision
Progressive weakening of an X-ray beam
Attenuation
Reduction in the energy involves process of
Absorption
Scattering
Combination
Transfer of energy from the primary X-ray beam to the atom in which the X-ray beam interacts as it passes through the medium
Absorption
Occurs following collisional interaction bet the primary X-ray beam and atoms of the medium
Scattering
Photon retains much of its energy
Forward direction
Photon lost much of its energy
Back scatter
Thickness of some material required to reduce the wan intensity to half of its original value
Half Value Layer
High HVL
High penetrating ability
Hard beam
Low HVL
Low penetrating ability
Deposit their energy in a medium fairly quickly
Soft Beam
Composed of different energy levels of radiation
Polyenergetic beam
Smallest unit of matter
Atom
