Among the information it has about potassium iodide: If you want to learn more about radiation and iodide tablets, a good place to start is at the Centers for Disease Control web site. Nuclear Regulatory Commission notes in a lesson plan for teachers that when you use a Geiger counter to determine how radioactive a substance is, you need to know what the background radiation level is so that you don't add that count to the reading of the substance you are testing. It's unlikely most of us are that expert. However, you should still see activity from gamma and beta particles even with the boot on.įor older revisions with a bleed button: Remember to always hit the bleed button with your power supply connected, after the tube power switch is moved from the ON position to the OFF position.Geiger counters, which measure radiation, can be had on eBay, but in the wrong hands (which means most of ours) may be an ineffective tool. The boot should be removed if you are needing to detect alpha particles. The Geiger tube comes with a red boot to protect the end window during, production, handling, and shipping. An enclosure is not absolutely necessary, but if you choose not use an enclosure, remember to be extra careful with the end window and high voltage regions.

Do not touch the end window of the Geiger tube and do not to touch any conductive region inside the area marked HIGH VOLTAGE when the Geiger tube is powered ON. The reason being when you move the switch into the OFF position, the high voltage lines are bled out through a resistor connected to ground, more information on this in the tutorial.Ī project box or enclosure is suggested. In order to turn the unit off, you must flip the tube power switch to OFF while the USB cable is plugged in or while the board is still connected to your power supply.

Note: While the Geiger counter is powered and the switch is in the ON position, the board contains exposed high voltage components.

Here at SparkFun, on average, we get about 20 counts a minute.Ĭheck out the random number generating Geiger counter tutorial for more information. Simply plug the unit into USB (make sure you have FTDI drivers installed), open a terminal program to the correct COM port at 9600bps, and you will see random bits being generated from the random background radiation. This is a USB powered Geiger Counter equipped with an ATMega328 that can be programmed in circuit using one of the programmers below. We've made some minor changes to the board layout, but functionality remains the same.

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