What Is a Geiger Meter?

The Geiger meter, also known as a Geiger counter or a Geiger-Muller counter, has been around for almost a century, but continues to evolve to meet new demands.

History

Hans Geiger, a nuclear physicist, invented the first version of the Geiger counter in 1911. He and physicist Walther Muller developed a more accurate and durable counter in 1928.

Purpose

The Geiger counter measures radiation created by cosmic rays and radioactive materials.

Parts

Geiger counters consist of a sealed metal tube filled with gas, a wire or needle, a voltage source and possibly a rate meter with a pointer and scale.

How It Works

The voltage source creates a current that almost flows through the gas from one electrode to the next. If radiation is present, it ionizes the gas, which then carries the current to complete the circuit. Audible clicks occur for each particle that passes through. A rate meter provides a visual measurement.

Prospects

In 2006, a team at the University of Michigan announced the development of a Geiger counter small enough to fit on a postage stamp. The device has potential for widespread use in large public venues that are potential terrorist targets.

References

• Massachusetts Institute of Technology: Geiger Counter
• University of Michigan News: Tiny Wireless Geiger Counter Detects Radiation