Build Your Own Geiger Counter
Build a fully functional Geiger Counter capable of measuring the three primary forms of radiation; alpha, beta and gamma radiation. The counter is sensitive enough to detect background radiation. In addition you can enhance the basic Geiger Counter by adding a Digital Meter Adapter, RS-232 Adapter with free Windows Radiation monitoring program or a Randam Number Generator. The windows 98/XP radiation program is free and available for downloading, more on this later.
The Geiger Counter produces an audible click and blinks a LED each time it detects a radioactive particle. Typically the counter clicks 10-20 times a minute due to normal background radiation. While the device is sensitive enough to measure background radiation, it is not suitable for measuring radon gas. There are Radon gas detectors that use an activated charcoal filter that are easy to use and more accurate.
Radioactivity is the spontaneous emission of energy from the nucleus of certain atoms. The most familiar radioactive material is uranium.
There are three forms of energy associated with radioactivity; alpha, beta and gamma radiation. The classifications were originally determined according to the penetrating power of the radiation, see Figure 1. Our Geiger Counter can detect the three types of radiation; alpha, beta and gamma radiation.
Alpha rays are the nuclei of helium atoms, two protons and two neutrons bound together. Alpha rays have a net positive charge. Alpha particles have weak penetrating ability, a couple of inches of air or a few sheets of paper can effectively block them.
Beta rays were found to be electrons, identical to the electrons found in atoms. Beta rays have a net negative charge. Beta rays have a greater penetrating power than Alpha rays and can penetrate 3mm of aluminum.
Gamma rays are high-energy photons. This has the greatest penetrating power being able to pass through several centimeters of lead and still be detected on the other side. Thick lead is needed to attenuate gamma radiation.