chapter 13 Difference between Ionizing Radiation and Nonionizing Radiation

Ionizing Radiation

•  Higher energy electromagnetic waves (gamma) or heavy particles (beta and alpha).

•  High enough energy to pull electron from orbit making the atom unstable which forms an ion pair.

Nonionizing Radiation

•  Lower energy electromagnetic waves. Not enough energy to pull electron from orbit, but can excite the electron.

NonIonizing Radiation :

Radiowaves – are used for radio transmissions, they are around us all the time

•  Can be detected by a radio receiver

•  Frequency = c/s (cycles per second)

•  Frequency is measured in Hz

•  The greater the frequency the shorter the wavelength

Microwaves – short wavelength, used to exite water molecules if food to cook it

Infrared Radiation – (infrared = below red)

•  Humans cannot see infrared light

•  We can feel infrared light as HEAT

Visible Light – contains all colors of the spectrum

Can be detected by :

•  Film

•  Human eye

•  Photoelectric cells

Ultrviolet Light – can be detected by:

•  Film

•  Photoelectric cell

•  Biological change – sunburn

•  Used commercially to kill bacteria

Ionizing Radiation :

X-Rays and Gamma Rays – high energy / very short wavelengths

•  The higher the energy of the photon the shorter the wavelength

X-Rays – are produced by an electron hotting a target (LINAC)

Gamma Rays – are emitted from the nucleus of radioactive substances (Cobalt 60 Machine)

** both x-rays and gamma rays have no mass and no charge**

*** the radiation we use is x-rays(photon beams) and some places have dual energy machines(photons and electrons)***

Electromagnetic Spectrum : 

Cobalt 60 Machine – releases a clean (homogenous) beam

•  Has an energy of 1.25 Mev all the time

LINAC – releases a spectrum of energies (wavelengths)

•  The beam is named for the highest energy beam the machine releases (for shielding purposes

•  For a 6Mev LINAC 6Mev is only 1/3 of the beam

•  Most of the energy from a 6Mev LINAC is 2Mev