Mastodawn

My #Radiascan701A #GeigerCounter died a while back. It acts normally, except it is insensitive to known-spicy objects. I finally got around to breaking the warranty sticker to peek inside. I measure around 230VDC across the GM tube, and it emitted a click when I touched the DMM leads to the contacts. Maybe the electronics are still working, but the tube lost vacuum?

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Mark J. Blair 5d ago

I don't suppose any of you hoopy froods know anything about debugging Geiger counters?

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Mark J. Blair 5d ago

I'm also tempted to use my counter's failure as an excuse to get one of those newfangled lowish-cost scintillation detectors which can do gamma ray spectroscopy, like one of the RadiaCode units or the new RadView AlphaHound AB+G. So tempting...

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Mark J. Blair 5d ago

I don't have the gumption to debug the Geiger counter more this weekend (I'm in the middle of a cold), but I think the most reasonable next step would be to remove the GM tube and see if it shows any sensitivity in a kludgy bench setup with my old HP 711A 0-500VDC power supply.

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Mark J. Blair 5d ago

I see some similar looking GM tubes on eBay from assorted eastern European countries, but priced around 1/3 the cost of a new mid-range RadiaCode scintillation detector.

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Mark J. Blair 5d ago

Oh, neat. After leaving the unit turned on for a while, it began emitting bursts of clicks with increasing frequency. There's a faint orange glow inside the tube. It still doesn't respond to known-spicy items which it previously had strong opinions about.

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Mark J. Blair

Indecision collapses
Pre-ordered the AlphaHound AB+G
Now the wait begins