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Building a Phosphorescence Detector
There's very little written about natural phosphorescence. Let's design a device that can spot it in the wild.
In theory, the idea was simple: place samples in a lightproof container, shine a UV light on them for a while, and then measure any residual glow with a photodiode circuit — as discussed in one of the recent posts. The plot is quite similar to the earlier one, but the effect is about two orders of magnitude weaker; the glow is actually visible with a naked eye, but only in total darkness and only for about a second after hitting the material with a UV beam. Elsewhere in the home, in my kids’ mineral collection, an unassuming chip of natural ruby exhibited surprisingly strong phosphorescence — yielding an ADC reading of about 2,000 at the 100 µs mark, then decaying to almost nothing at 20 ms.
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