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Comment by metadat | Hacker News Reader

The truly burning question I'm left with after reading TFA is:

How much extra radiation does the RPi-eiger counter introduce to the scene?

What do you mean? That the external equipment itself is somehow radioactive, or what?

If OP is worried about the equipment being radioactive, I'd like to reassure that Geiger counter electronics and RPi are not particularly more radioactive than any other household or natural object. A Geiger–Müller tube is just a canister of low pressure Penning mixture, mostly noble gasses like argon or neon, and some other gasses added for quenching. A voltage is applied across leads of the tube, and a count is detected whenever the tube conducts due to being excited by passing ionizing radiation. There's nothing in this setup that creates ionizing radiation.

Interesting to note that, semiconductor encapsulating epoxies are often manufactured to be extra non-radioactive, as presence of even small amounts of naturally occurring trace radioactivity, when directly against the semiconductor die without any distance to attenuate alpha particles, can cause circuits to experience much more errors like bit flips or latch up.

I'm curious why there is no solid state detector? We've had tons of advancements in solid state optical devices like emitters. But have there been no advancements to radiation detection in 100 years since the G-M tube was invented?

There absolutely are solid state detectors and major innovations! People nowadays use scintillator detectors with photomultipliers, for things like research and more precise counters.

Scintillation counters use some material, often a plastic, that "scintillate," meaning it can absorb high energy particles and re-emit them as lower energy photons. The low energy photons are then amplified though various means, from photoelectric tubes similar to earlier night vision technology, to all integrated silicon chips [0]

In general, scintillation counters have the benefit of more precision and better ability to detect alpha particles (like GM tubes with quartz windows) and also don't require high voltages to drive. I think they're a cool example of technology modernization, where we go from the somewhat janky, almost steampunk aesthetic of soviet geiger tubes driven by crude looking flyback transformers, to low voltage, highly precise, extremely integrated and miniaturized modern detectors powered by semiconductors.

[0] https://www.onsemi.com/products/sensors/photodetectors-sipm-...

Interesting! Thanks for the good information.

Maybe you're thinking about electromagnetic radiation. I highly doubt the RPI would produce gamma rays, but I can assure you that it produces radio waves. I guess it depends what kind of radiation you're measuring.

In terms of radio waves, besides intended emissions like WiFi, well designed modern circuits release little spurious electromagnetic radiation. There's a whole field of engineering that goes into this, called electromagnetic compatibility. Basically the layout of the board feature ground planes and return vias that improve signal integrity while reducing any unwanted emissions.

Avoiding interference is not just altruistic due to the reciprocal property of electromagnetism: a design that does not accidentally create antennas and emit junk, is less susceptible to receiving interference from external sources

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