Basics of Radiation Exposure

Using safety information from the World Nuclear Association and U.S. Environmental Protection Agency, this Basic Radiation Fact Sheet discusses the physical properties of radiation, dose information, conversions, and more.

Background radiation
~3 mSv/yr (300 mrem/yr) in North America and slightly higher in Asia. 88% of background radiation comes from natural sources (half of this from radon gas), almost all the remaining radiation comes from medical sources.
Safety Levels
American regulatory limit for occupational exposure: 50 mSv/yr (5 rem/yr). This limit was chosen because it is the lowest rate at which there is evidence of cancer being caused in adults. Pregnant women and children should have no more than a 10th of this (5 mSv/yr or 500 mrem/yr). A lethal full-body dose for a man is around 4 - 5 Sv (400 - 500 rem) in a short time period.
Radiation Exposure
vs. Distance
if the distance from the source is doubled, the exposure is reduced by a factor of 4.

Geiger Counters vs. Scintillation Detectors

Although these two types of radiation detectors are used for many of the same purposes, they are very different in the way they detect radiation and what they can pick up.

Geiger counters
Geiger counters use Geiger-Mueller tubes, which have low sensitivity and a wide range and are the most commonly used detectors on the market. The downside to these kind of detectors is that they are much less sensitive to radiation than other detector types and cannot differentiate between radiation types. They are also too slow to detect moving radiation, but are cheap and durable.
Sodium Iodide (NaI(Tl))
Cesium Iodide (CsI(Tl))
Sodium Iodide (NaI(Tl)) and Cesium Iodide (CsI(Tl)) are also common gamma radiation detectors but, unlike Geiger-Mueller detectors, they are fast, sensitive (up to 100 times more sensitive than Geiger-Mueller detectors), and can measure the actual energy of gamma rays. Scintillation detectors are ideal for scanning people or cargo on the move for radiation, as well as looking for tiny amounts of radiation in food or water to make sure it’s not contaminated. D-tect Systems’ mini rad-D and mini rad-V devices use CsI(Tl) radiation detectors equipped with photo-multiplier tubes (PMT) that detect radiation from tens of meters away.

View the full D-tect Radiation Basics Sheet.

Radiation Contamination in Food and Water: What's the Risk?

We discuss the basics of radiation contamination in food and water, and the effect the recent crisis in Japan has had on the international community. We cover checking food and water supplies as well as recent trends in detection.

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Am I at Risk of Radiation Exposure?

This article puts the risks of radiation contamination in perspective by discussing relative doses for common radiation sources, the risks involved in contamination, and some simple guidelines on how to protect individuals and families from contamination.

View the full article Am I at Risk of Radiation Exposure?

Protecting the Public from a Nuclear Power Plant Radiation Leak

Many people around the world live near nuclear power plants and have questions about much risk nuclear radiation actually poses. This article discusses how to stay safe and how instruments such as dosimeters and radiation detectors that are used in response to a crisis.

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Radiation Exposure: What Can I Do?

The experts at D-tect Systems have put together some basic information on the effects of radiation as well as suggesting some guidelines for mitigating radiation risks, such as using a dosimeter and radiation detector, and having emergency supplies on hand.

View the full article Radiation Exposure: What Can I Do?

Radiation Detector Overview

Since each radiation security situation is different, it is important to choose the right radiation detector for the job. This overview contains basic information about of the following detector types:

  • Geiger-Mueller (GM)
  • Sodium Iodide (NaI(Tl)) and Cesium Iodide (CsI(Tl)
  • Plastic Scintillators (PVT)
  • Lanthanum Bromide (LaBr3)
  • High Purity Geranium (HPGe)
  • Cadmium Zinc Telluride (CZT)
  • Helium-3 (He3)

View the full Radiation Detector Overview.

For more information on the following radiation safety topics, visit the D-tect Systems Blog.

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