How does geiger counter work

They can detect various types of radiation, such as gamma rays or alpha and beta particles. It is the primary sensing element of the counter. Geiger counter is one of the most well-known instruments used for radiation detection in the world. The principle for the creation of a Geiger counter was first realized in , but the instrument could not yet be produced then. Hans Geiger was the physicist that established the principle at the Victoria University of Manchester.

A Geiger counter looks like a metal cylinder or a tube, and it is filled with low-pressure gas. The gas is sealed in by a window made of plastic or ceramic. A metal wire is running through the middle of the tube, and it is connected to a positive voltage. This means that there is a strong electric field between the wire and the outside of the tube. Those can be operated by a single hand. There are three major types of radioactivity; Gamma, Beta, and Alpha radiation.

Less expensive Geiger counters just detect gamma and beta radiation. Prefessional models detect all types of radiation, alpha, beta and gamma. A typical Geiger counter consists of a Geiger-Mueller tube, a visual indicator or meter readout analog or digital , and an audio indicator. Typically the audio indicator sounds a "click" for each radioactive particle detected. Digital Geiger counters not only offer visual digital readouts on an LCD display, but they typically also have audio ports for external speakers, as will as data ports for readout on computers and data loggers.

Each output pulse from the GM tube is a count. The counts per second give an approximation of the strength of the radiation field. The response curve of a GM tube shows the relationship between counts and radiation feild.

It allows the manufacturer to get an approximation calibration using a cesium source and response curve. See chart is shown in Figure 3. However true calibration requires that a geiger counter have an NRC certification to its accuracy.

Law enforcement personnel may use sophisticated versions of the devices to detect the transportation of illicit radioactive materials , and many emergency responders carry them as well, according to the Department of Homeland Security. In Japan, personal Geiger counters became hot sellers after the accident at the Fukushima Daiichi nuclear power plant. They're also used by prospectors to find uranium and other minerals. But Geiger counters also have limitations.

Sign up for our Newsletter! Mobile Newsletter banner close. Mobile Newsletter chat close. Mobile Newsletter chat dots. Mobile Newsletter chat avatar. Mobile Newsletter chat subscribe. How Do Geiger Counters Work? Geiger counters used to be fairly big and bulky devices, but today can be handheld like this one or even downloaded as an app on a smartphone.

Hans Wilhelm Geiger , left, and Ernest Rutherford with their apparatus for counting alpha particles. Together they worked on the radiation detector invented by and named after Geiger. In this early model of a Geiger counter, a low pressure gas is held in a copper cylinder, which an electrical current runs through.