Radiation Frisker is a handheld, wand-shaped radiation detector, featuring digital display and an internal pancake, halogen-quenched, Geiger-Mueller detector. Geiger counters are mainly used for portable instrumentation due to its sensitivity, simple counting circuit, and ability to detect low-level radiation. Although the major use of Geiger counters is probably in individual particle detection, they are also found in gamma survey meters. They are able to detect almost all types of radiation, but there are slight differences in the Geiger-Mueller tube. For alpha and beta particles to be detected by Geiger counters, they must be provided with a thin window. This “end-window” must be thin enough for the alpha and beta particles to penetrate. However, a window of almost any thickness will prevent an alpha particle from entering the chamber. The window is usually made of mica with a density of about 1.5 – 2.0 mg/cm2 to allow low-energy beta particles (e.g., from carbon-14) to enter the detector. Effective window diameter in a Frisker is about 50 mm.
The Frisker detects alpha, beta, gamma, and X-ray radiation. Typical Frisker detects:
- gamma rays and X-rays down to 10 keV typical through the window, 40 keV minimum through the case.
- alpha particles down to 2 MeV.
- beta particles down to 0.16 MeV
Efficiencies vary, depending on energy and isotope. The Frisker is ideal for general purpose survey in laboratory use, nuclear power plant frisking, emergency response, border patrol, airport security, and other applications.