Geiger Counter with USB Capability

Figure 1 

The project is concerned on building a detector for ionizing radiation known as Geiger counter with the interfacing on a microcontroller that is capable of connecting to a PC through a USB.

There are many forms of radiations that can be detected from radio elements such as alpha, beta, or gamma, but beta and gamma are the more sensitive radiations. The Geiger-Muller device is a tube filled with a gas with two electrodes and produces an electrical impulse when fast-moving charged particles traverse the counter where a high potential is applied between the electrodes. A temporary conductive path between electrodes is created when an ionizing particle arrives. An electronic amplifier can detect the resulting current.

A Geiger counter contains a high voltage regulator which consists of a 50Hz oscillator with a classical NE555 circuit, transformer, voltage multiplier, and voltage regulator. The regulator stops the oscillation when the potential is too high. A Zener diode is being used to limit the voltage at 550V. Along with the generator are a Geiger tube, an amplifier, and a monostable.

Other kinds of tubes can be used but the voltage should be adjusted to the tube’s characteristic.

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