How to Use a No Amplifier Geiger Counter

Geiger counters are frequently used in high-radiation areas

Geiger counters are one of the most common types of radiation detection tools. They are "counters" in the sense that they count the number of radiation particles that enter a sensor. The Geiger counter displays this count in one of a few ways. One common approach is to show the count with an LCD display or dial. Most Geiger counters can also output the count in audio form, typically a clicking noise where each click corresponds to the detection of a particle. Many counters use an amplifier circuit to improve detection ability, but there are still some that do not.

Instructions

1. Flip the "On" switch of the Geiger counter (it should be clearly marked on the front of the case). Depending on whether your Geiger counter has a sound output, it may start to click irregularly as it detects the background radiation of the room you are in. The dial should show this as well, with a steady 10-20 counts per minute.

2. Point the probe of the Geiger counter at the object you wish to test the radioactivity of. The probe has a small mica "window" in the front through which alpha and beta particles, as well as gamma rays, can enter the gas-filled chamber (Geiger-Muller tube) which the counter uses to detect them.

3. Monitor the readouts of the Geiger counter. If pointing the end of the probe at the specimen you are measuring causes an increase in the rate of clicking or a jump in the dial then it is probably more radioactive than the base-level for the area you are in. If there is no change in the readouts of the counter than it is likely that the specimen is no more radioactive than anything else nearby.

Tips & Warnings

• Some Geiger counters do not have readouts on the actual counter, but output to a computer via a USB cable. In this case, follow the instructions that come with the instrument.

• Be sure to use a level of radiation safety measures appropriate for the specimen you are experimenting with. If it is simply a household item it is unnecessary to take any special precautions, if you are working with a material known to be radioactive (tritium, uranium, etc.) it is important to be more careful. Do not touch the sample directly, for instance, and keep it in a fully enclosed container.

References

• Black Cat Systems: Geiger Counter