BASIC CONCEPTS OF RADIATION (PART 2) Flashcards
Types of Electromagnetic Radiation
Radiowaves, Microwaves, Infrared, Visible light, Ultraviolet light, X-rays, and Gamma rays
Lowest energy, lowest frequency, and longest wavelength
Radiowaves
Highest energy, highest frequency, and shorter wavelength
Gamma rays
Range of wavelengths or frequencies over which electromagnetic radiation extends
Electromagnetic Spectrum
- Longest wavelengths
- carry signals for televisions and cellular phones
Radiowaves
Relative size of radiowaves
Mountain range
1.) waves which heat our food in microwave oven
2.) remote sensing (used for radar; doppler radar for weather forecasts)
1.) Longer microwaves, closer to a foot in length
2.) Shorter microwaves
Relative size of microwaves
Dice
- Also known as “IR”
- lies between visible and microwave portions
- cannot be seen by human eye
Infrared
Below the red spectrum of visible light
Infra
Relative size of Infrared
Pin tip
Heat or thermal radiation (radiation produced by motion of atoms and molecules in an object)
Primary source of infrared radiation
- Is named because of the wavelength of infrared rays is a bit longer than red days
- Is essentially heat radiation
Infrared radiation
- part of infrared spectrum closest to visible light
- higher energy
Near Infrared
Closer to microwave region
Far Infrared
Region between the two
Mid-Infrared
- only electrogmagnetic waves visible to human eyes
- seen as colors of the rainbow
- each color = different wavelength
- optical light
Visible light
Relative size of Visible light
Bacteria
longest wavelength, lowest frequency, lowest energy
Red
shortest wavelength, highest frequency, highest energy
Violet
all waves seen together
white light
Light shines through
prism
white light broken apart into colors of the visible light spectrum
prism
shorter wavelength than visible light
Ultraviolet Light (UV)
Relative size of Ultraviolet Light (UV)
DNA
source of full spectrum of ultraviolet radiation
sun
most harmful, completely absorbed by atmosphere
UV-C rays
harmful, causes sunburn; increases risk of DNA and other cellular damage in living
UV-B rays
- NUV
- closest to visible light
Near Ultraviolet
- EUV
- closest to x-rays
- most energetic
Extreme Ultraviolet
- FUV
- between near and extreme UV regions
Far Ultraviolet
- shorter wavelength
- higher energy than UV rays
X-rays
X-rays are first observed and documented in
November 8, 1895
who discovered X-rays?
Wilhelm Conrad Roentgen
- smallest and shortest wavelength
- most energy of all the waves in electromagnetic spectrum
- generated by radioactive atoms and nuclear explosions
- used for medical advantage as it can kill living cells (cancer cells)
Gamma rays
Relative size of Gamma rays
Atomic Nucleus
- any process by which electrically neutral atoms or molecules are converted to electrically charged atoms (ions)
- one of the principal ways that radiation transfers its energy to matter
Ionization
- carried by any of several particulate and rays given off by radioactive material, x-ray machines, and nuclear reactions
- radiation with enough energy to remove tightly bound electrons from orbit, which causes the atom to become charged or ionized
- includes alpha particle, beta particle, gamma rays, x-rays
Ionizing Radiation
electrically charges atom
Ions
- includes charged particles with sufficient energy to ionize atoms
- all must be moving at relative speed to carry required kinetic energy
- when charged particles pass through materials, they ionize atoms
- involves large energy transfer from primary charged particle to an electron of the medium
- deposits energy at localized range in materials
Directly Ionizing Radiation
may result in production of a relatively energetic secondary electron
Delta ray
which itself will go on to produce multiple ionization events
Delta ray
- not capable of producing multiple ionization events
- includes uncharged particles
- deposits energy along its whole path
Indirectly Ionizing Radiation
uncharged particles
photons: x-rays and gamma rays, neutrons
- radiation that has enough energy to cause the atoms in molecule to vibrate but not enough to remove electrons
- not capable of ionization, but capable of excitation
- ultraviolet radiation (except high energy end of UV-spectrum), visible light, infrared radiation, microwaves, radio waves = ?
- extremely low-frequency radiation
- very long wavelength
- frequency ranges from 100 Hz or less
Non-Ionizing Radiation
relative size of x-rays
atom
- stream of atomic or subatomic particles
- may be positively charged or negatively charged or not at all
- carry energy in the form of kinetic energy or mass in motion
- involves tiny fast-moving particles that have both energy and mass
- primarily produced by disintegration of an unstable atom
Particulate Radiation
positively charged
alpha particles
negatively charged
beta particles
no charged at all
Neutrons
particulate radiation is also known as
Corpuscular radiation
- relatively heavy, high-energy subatomic particle
- conists of 2 protons and 2 neutrons
- ernest rutherford
- tend to be very large atoms ( high atomic numbers)
Alpha Particles
treat cancer
Radium-226
static eliminator in paper mills and other industries
Polonium-210
smoke detectors
Americium-241
- high velocity electrons
- electrical charge of -1. (negative)
- high speed
- Henri Becquerel, in 1900 showed that this particle is similar to electron
Beta Particle
depends on how much energy they have
speed of individual beta
treat thyroid disorders such as cancer, graves diseases
Iodine-131
radioactive tracer in medical and agricultureal studies
Strontium-90
life scinece and drug metabolism studies to ensure safety of potential new drugs
Tritium
- able to penetrate tissues and organs of human body when the radiation source is outside the body
- high speed nuclear particles
- exceptional ability to penetrate other materials
Neutron Radiation
energies below thermal energies typically corresponding to meV and sub meV energies
Cold Neutrons
neutrons colliding with atomic nuclei either pick up energy if they are moving slower than colliding nucleus, or lose energy if they are moving faster
Thermal Neutrons
energies between 100’s of eV to 0.05 or 1 MeV
Slow Neutrons
between 0.5 and 10-20 MeV, energies of neutrons = emitted by fission sources
Fast Neutrons
above 20 MeV
High energy neutrons
- antielectron
- antiparticle or antimatter counterpart of electron
- electric charge = +1e
- same mass as an electron
- low energy positron = colllides with low energy electron = annihilation
Positron
Carl D. Anderson in 1932, concluded the existence of a positive particle of electronic mass (positive electron)
First and crucial step in discovery of positron
