why do Geiger counters make that strange noise and why is it so different to other sensors that just beep?
In: Technology
The operating instrument in a Geiger counter is a Geiger-Muller tube, which is basically an electrified enclosure where the can is the negative electrode, and a rod down the middle is the positive electrode. The can is filled with gas at low pressure, and the electrodes are excited to a high voltage, but not quite high enough for a spontaneous arc of electricity between the core and the can. The gas ordinarily does not conduct electricity, but when a high energy particle or photon (ionizing radiation) passes into the assembly and collides with a gas molecule, it temporarily ionizes the gas, making it conductive. This provides a sufficiently conductive path for electricity to briefly arc between electrodes via the ion. Each such event represents a count, and often Geiger counters will have audible feedback of these electric arc events, which is the sound you are referring to.
In the detector, the tube, there is a metal rod and an inert gas like neon. When ionizing radiation enters the tube those particles push the particles around in the tube and when there is enough it creates electricity in the tube which the rod absorbs and the current it sent to the speaker. The current causes the speaker components to jerk and that causes the popping noise we here.
Because geiger counters are *old school*.
Geiger counters have a tube of inert gas. When an ionising particle passes through this tube there’s a chance it will ionise an atom. This effect is amplified and turned into a little surge of current. That current can move a pointer on a dial or be fed into a speaker, where it sounds like a click.
Now of course you *could* build something more complex that makes a speaker beep rather than click. But why complicate something that works?
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