A Geiger counter — named after Hans Geiger, a German scientist from the early 1900s who worked on detecting radiation — is an instrument that can detect radiation. Geiger counters can tell you there is radiation around you, but it can’t tell you the original source of the radiation, what type it is or how much energy it contains.
The United States Nuclear Regulatory Commission (USNRC) explains how these instruments work on its “What is a Geiger Counter” page. However, personal radiation detectors detect and localize radiation sources generated by manmade devices such as nuclear weapons, improvised nuclear devices (INDs) or radiological dispersal devices (RDDs. They are worn on the person and provide radiation detection in the immediate area around the wearer. The instruments can quickly pinpoint the location of radioactive sources easily, allowing the wearer to respond to the exact location of a threat.
Types of Personal Radiation Detectors
Personal radiation detectors offer the functionality of traditional Geiger counters, while delivering features not available in traditional Geiger counters. These lightweight instruments offer an improved range of detection of multiple types of ionizing radiation, even in the same unit – alpha, beta, x-rays, and gamma. They also feature different types of interfaces and a catalog of optional accessories for wireless reachback, rechargeable batteries, and extension poles to maintain good ALARA principles. Variations include units that can monitor dose rate, stay time, and peak values. Intrinsically safe options are available for users that may operate them in explosive environments.
Some examples of personal radiation detectors that go beyond Geiger counter capabilities are:
- Basic Survey Meters are lightweight personal radiation detectors that are used when the direction or location of the source of radiation is unknown or all around the person. They continuously monitor radiation exposure in any nuclear or radiological emergency and display Gamma count rate, dose rate, accumulated dose, remaining stay time, and peak dose and count rate values.
- Gamma surveys are used when one needs an extended energy range such as establishing hot and warm zones. Nuclear medicine personnel who work with medical isotopes or in facilities that use radiation need to monitor their risk of exposure at all times. The instruments are usually portable and highly accurate with excellent dose rate energy response. The instruments displays Gamma count rate, dose rate, accumulated dose, stay time, and peak values .
- Surface contamination and Post accident response instruments are used to detect surface contamination, as well as personal dose rate monitoring, all in one unit. First responders need to quickly identify mixed radioactive surface contamination in facility and field environments. These instruments offer contamination and dose rate measurement tools for characterizing alpha, beta, gamma and X-ray radiation in a single unit.
- Portable survey meters with full range of modular probes are used in situations where there are hard to reach areas or areas with high radiation and ALARA must be practiced. They usually have built-in a calibrated dose detector and external connections to read a wide range of probes, including Geiger Muller.
An alternative to Geiger Mueller detectors, scintillation detectors detect even the smallest amounts of artificial radioactivity. They are especially useful when searching for small amounts of hidden or shielded radiation. Many have capability to also identify the radioactive isotope. Scintillation detectors can work as standalone instruments for security screening events, or can be paired with a Geiger Muller detector to provide detection capability and personal dose monitoring to extremely high dose rates.
Summary: Personal Radiation Detectors offer much more than Geiger counters
To quote William Shakespeare: “What’s in a name? that which we call a rose by any other name would smell as sweet.” When it comes to radiation detection, the Personal Radiation Detector name means so much more than a Geiger counter.