Check Out Our Reference Guides on Radiation Safety

Quick Reference Guide

  • Types of Radiation
  • Radiation Shielding
  • Typical Isotopes
  • Measuring Radiation
  • Laser Safety

Radiation is Everywhere: Sources of Radiation

Natural radiation sources include cosmic rays from space, cosmogenic radionuclides, and primordial radionuclides and their progeny. Some of these radionuclides are found in the food we eat, the air we breathe, and even in our own bodies. We have limited practical options for avoiding exposure to many of these natural radiation sources.

Man-made radiation sources (of which we can help control) include diagnostic imaging and radiotherapy machines, sources used for nuclear medicine, sources used for radiography and well logging, nuclear power plants, particle accelerators, consumer products, and laser cutters and welders.

Types of Radiation

Ionizing Radiation


  • two protons and two neutrons
  • shielded by a piece of paper
  • cannot penetrate the dead skin layer
  • concern for internal exposures


  • electron
  • shielded by plastic (low Z mat.)
  • 70keV beta to penetrate the dead skin
  • highest concern for localized skin exposures


  • electromagnetic energy
  • gamma and x-rays
  • shielded by lead (high Z mat.)
  • can penetrate deep tissue


  • From the atom nucleus
  • shielded by water (hydrogen)
  • can make items radioactive

Non-Ionizing Radiation


  • 180nm–1mm wavelength (ANSI Z 136.1)
  • eye and skin hazard
  • ancillary hazards (Fire, LGAC)
  • shielded like light (high power requires curtains)

Microwave & Rf

  • large spectrum
  1. Microwave 300MHz–300GHz
  2. RF 3kHz–300GHz
  • Radio, telecommunications, etc.
  • in research, industry, facilities
  • main hazard (heating & burns)

Magnetic Fields

  • flying metal objects hazards
  • posting above 5 Gauss
  • pacemaker hazard
  • electronic de-activation (e.g. credit cards)


  • Eye and skin hazards
  • Cancer (prolonged exposure)
UV-C 190–290 Skin & Eye
UV-B 290–320 Skin & Eye
UV-A 320–400 Cataracts

Having the appropriate radiation shielding when working with radioactive material can greatly decrease the potential for exposures. It is also important to understand that certain shielding material should not be used for other radiations.

Examples of improper use include:

  1. Lead (high-Z material) should not be used to shield beta radiation because it can create bremsstrahlung radiation.
  2. Lead can be used for shielding alphas but so can paper (which is much cheaper)

Presented here is a simple list of popular isotopes (referred to as CHIPS) and their properties.

Not all radiation detectors can be treated as equal. The most important aspect of any detector is understanding its capabilities and limitations. Although we can help you choose the correct detector for your needs, following the information presented here can also be helpful.

  1. Determine whether you want to measure radiation exposure or radioactivity.
  2. Determine what configuration will meet your needs (portable, swipe counter, gamma spectroscopy, effluent, etc.)
  3. Compile a list of types of radiations (beta, gamma, etc.) and the isotope if possible, to determine the energy of the radiations that need to be measured.
  4. Research detector manufacturers and detectors capable of completing the task. Communicate with the manufacturer and even request a trial or demonstration of the device, if possible.

Radiation Detector Vendors (Some)


Laser is an acronym for Light Amplification by Stimulated Emission of Radiation. Lasers emit light on the electromagnetic spectrum that can be very useful but also hazardous if not controlled properly. Lasers are referenced as specific devices having the properties listed below from wavelengths of 180nm–1mm (ANSI Z136.1).

Lasers emit light that is:

  1. Directional: does not expand as easily as regular light (travels much further),
  2. Highly coherent: identical in wavelength and phase,
  3. Monochromatic: identical wavelength (very narrow band)