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I have to detect a small radiation from this tags and I´m looking for some ideas how I can do this with some kind of small electronic circuit (or lecture to read how to do it) - not with a Geiger-Müller counter!

My current idea is to use an array of PIN diodes (see here) to detect the tags. But I don´t know if this solution works for my problem or if I can use some better solution (maybe an IC?).

So I´m looking for some other ideas of how I can do this.

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  • \$\begingroup\$ Oh thats an interesting idea. Does the camera sensor need special requirements to do this or can I use some cheap and low resolution sensor to do it? \$\endgroup\$
    – Kampi
    Aug 14, 2019 at 5:28
  • \$\begingroup\$ Great, that sounds like an good idea. I will look for more information about it. Thank you for the hint :) \$\endgroup\$
    – Kampi
    Aug 14, 2019 at 5:34
  • \$\begingroup\$ Thank you again Marcus :) \$\endgroup\$
    – Kampi
    Aug 14, 2019 at 5:35
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    \$\begingroup\$ What's wrong with the PIN diode solution? \$\endgroup\$
    – JRE
    Aug 14, 2019 at 5:48
  • \$\begingroup\$ @JRE nothing. I´m just looking for additional ideas and collect information. So I´m already open for additional ideas. \$\endgroup\$
    – Kampi
    Aug 14, 2019 at 5:55

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Digital camera sensors would be a promising lead.

From that same publication, a picture that shows shot noise induced by ionizing radiation hitting the sensor.

Radiation-induced noise

Note that of course larger sensors simply have a higher chance of getting hit; and better sensors lower-noise amplification and digitization, but for a start: A not-too-cheap webcam would probably do.

Note that webcams, especially the really cheap ones, often connect the sensor to an all-included digital IC that does an overboarding lot of noise reduction (exactly the opposite of what you want) and JPEG compression and whatnot, just to compensate using the cheapest image sensor available.

So, spending 50€ on a HD cam does sound like a good idea. The publication uses a small NTSC/PAL camera module, but honestly, I'd probably try to avoid the additional Digital-to-analog conversion to get an analog TV signal.

Here's a Finnish Guy doing a test with a rather large-sensor'ed DSLR, and he concludes it works well. Note that he says "Camera took no damage" – don't know how he can assess that at the point, seeing that flash memory is pretty much an excellent radiation sensor, too (ask the folks who need to build satellite electronics), and firmware memory corruption might not be the first thing to notice. I wouldn't try to use consumer flash memory as sensor, though, as it has copious amounts of self-repair / error correction mechanisms that will hide radiation from you.

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  • \$\begingroup\$ hey, you don't have to accept this quickly. Others might have good ideas, too! \$\endgroup\$ Aug 14, 2019 at 5:43
  • \$\begingroup\$ Yeah, this was too hasty :) \$\endgroup\$
    – Kampi
    Aug 14, 2019 at 5:53
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    \$\begingroup\$ Radiation doesn't see a pixel (whatever it's fabrication design) as a uniform sphere. It sees it as an oddball shape. For example, if the radiation path takes it face-to-back, the response is quite different than if the radiation path is left-across-pixel-to-right side. In a Hamamatsu detector I was using, I'd easily see a factor of ten difference based upon angle of incidence in the number of electrons swept up by the photodiode. If sensitivity is fair (say a few tens of femptoamp detection level), sea level cosmic rays are easily detected every few seconds with 1cm x 1cm detector. Just FYI. \$\endgroup\$
    – jonk
    Aug 14, 2019 at 6:51

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