If you want to determine radioactivity, nothing truly beats a Geiger counter: compact, rugged, as well as fairly simple to use, they’re by far the most commonly utilized tool to find ionizing radiation. However, a number of other techniques have been utilized in the past, as well as while they may not be extremely practical today, recreating them can produce an fascinating experiment.

[Mirko Pavleski] utilized quickly obtainable elements to develop one such gadget understood as an alpha radiation stimulate detector. invented in 1945, a stimulate detector contains a strong electric field into which discharges are triggered by ionizing radiation. Unlike a Geiger-Müller tube, it utilizes routine air, which makes it sensitive only to alpha radiation; beta as well as gamma rays don’t cause sufficient ionization at ambient pressure. Fortunately, alpha radiation is the primary type emitted by the americium tablets discovered in old smoke detectors, so a usable source shouldn’t be as well difficult to find.

The building of this gadget is extremely simple: a few thin copper wires are suspended above a round metal can, while a affordable high-voltage source provides a strong electric field between them. Sparks fly from the wires to the can when an alpha source is brought nearby; a series resistor limits the present to ensure the wires don’t overheat as well as melt.

Although not truly practical as a measurement device, the stimulate detector can nonetheless be utilized to perform simple experiments with radioactivity. As an example, [Mirko] demonstrates in the video embedded below that alpha bits are stopped by a piece of paper as well as therefore present no instant risk to humans. The high voltage present in the gadget does however, so care must be taken with the detector more than with the radiation source.

We’ve seen a number of homebrew Geiger counters, some developed with lots of duct tape or with the great old 555 timer. however you can likewise utilize photodiodes or even specific kinds of plastic to visualize ionizing radiation.