Radiation monitoring equipment that protects people from excessive radiation exposure comes in three types. The most familiar and widely used is probably the radiation detector. Individual radiation monitors, badges, and “pens,” are not as well known outside certain occupations in mining, energy, and research. Radiation area monitors are the third type of detector. These devices are, as the name implies, used when radiation in an area of detection needs to be measured and recorded versus checking a specific object or person for signs of excess radioactivity. They can be classified in several ways, which are easier to understand if you remember the basics of radiation monitoring and detection.
A Review of Radiation Monitoring Technology
Radiation detector gear uses several different technologies to detect and measure radioactivity. Within the categories below, you will find a variety of specific ways of using the technology to create different devices.
Different devices serve to measure different aspects of radiation. Sometimes you want to know the type of radiation (x-ray or gamma ray, beta versus alpha), and other times you want to know the intensity of radiation coming from a source. In still other cases, you want workers to know how much radiation they have been exposed to. Area monitors detect radiation levels, while badges or pen-type monitors will indicate the dose a person receives, in rems or rads. In some situations, you need to know both, while other cases only require you to know only one or the other. Finally, the distinction between ionizing and non-ionizing radiation can be important too.
Scintillation
These tend to be highly sensitive devices that not only detect almost any amount of radiation but can differentiate between natural and artificial sources, including the nature of the artificial source. They are used for gamma ray and neutron (beta) detection.
Ionization Chamber
This category of radiation area detection device measures the production of charged particles, ions, generated by emissions from a radioactive source. These detectors are limited in that they only measure the strength of a source not the type.
Geiger-Muller
Devices using a Geiger-Muller tube are almost synonymous with the term “radiation detector” thanks to the long-running popularity of Geiger counters. In short, these devices use a gas-filled tube that intercepts some radioactive particles or waves and generates a signal. GM-type detectors deliver both a count (number of radiation events per unit of time) and the amount of radiation present.
Area radiation detection demands different technology depending on the setting and type of radiation hazards anticipated in that environment.
Tools for Radiation Area Detection
Radiation monitoring devices for checking surfaces, packages, vehicles, or individuals use similar technologies to area radiation monitors. Those designed to monitor an area versus a person can be placed in one of two categories:
Interlock monitors – These devices measure gamma rays, x-rays, and/or neutron emissions and cannot automatically lock personnel out of a contaminated area. They will also be able to report the level of radiation available.
Airborne particulate monitors – As the name suggests, these monitors detect radioactive particles in the air and sound an alarm if a dangerous level of radiation is detected. They may use large silicon-based detectors. These devices would monitor radiation levels, of course, but also record radiation data.
Radiation alert monitors — As well as other makes, will have radiation monitoring software either included or available at extra cost. Historical data may be useful in some settings. Other settings or industries operating under different rules may require reporting. So, it is important to know that this capability exists.
While function matters, note that area monitors may be classified in diverse ways. Their main function, serving as an interlock monitor or radiation alert monitor may be assumed or combined with other functions. For example, these are some classifications you may find for specialized uses:
Noble gas monitors – These radiation area monitors are useful for measuring beta radiation in nuclear facilities.
Gamma and neutron radiation monitors – These radiation detectors do pretty much what the label indicates. They may use scintillation or solid-state sensors, or Geiger-Muller tubes.
Iodine monitor – This niche products measure gamma-ray activity associated with isotopes of this widely used element. These devices may use other technologies but most likely you will find one using NaI(TI), sodium iodide doped with thallium, to measure radiation events.
These diverse ways of categorizing radiation monitors hint at their wide-ranging applications.
Applications of Radiation Area Monitors
Because radiation sources vary so much in their nature, and especially in the type of hazardous radiation they emit, no single type of detector is useful for every application. Medical labs, mining operations, nuclear research centers, nuclear power plants are examples of environments where monitoring needs may differ. A lab that handles radioisotopes may be concerned with high energy neutron emissions from their research materials. Some research labs may need radiation area monitors for gamma rays, primarily.
Different Area Monitoring Needs Call for Different Technology
Area radiation monitors may be classified either by their main function, of which there are two, or by their method of operation. Some vendors and users may think in terms of the specific task a device performs, such as monitoring iodine or neutron sources. S.E. International carries the Radiation Alert ® line radiation area monitors with models suitable for most any commercial, national security, medical, industrial, or scientific application.
