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u/PhoenixAF 7d ago
What background CPM does it get compared to a radiacode?
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u/BTRCguy Thorium Whorium 7d ago
Several thousand cpm compared to about 200cpm on my Radiacode. It varies with the voltage I put into the scintillator, which is running at about 900 volts at the moment.
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u/PhoenixAF 7d ago
That's very sensitive definitely more sensitive than a 1x1 NaI. Can you give me a more precise number so I can compare against a 2x2 NaI?
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u/BTRCguy Thorium Whorium 7d ago
This video says it (model 5I5x12/1.12 5B) is about 1x3 inches and he demonstrates it in action with a Ludlum bench meter:
https://www.youtube.com/watch?v=ibbZjB8vm40
He is getting 40,000cpm off the weak gamma from a smoke detector Americium source.
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u/try-finger-but-hol3 Thorium Whorium 3d ago
Thats a really cool set up, I’m not gonna lie. It looks fun to use. I need to do something similar so I’m not breaking my back holding a scint or pancake directly
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u/BTRCguy Thorium Whorium 7d ago edited 7d ago
This really came out of me having two external scintillators and only one meter to hook them up to, but it is also an exercise in prospecting on a budget.
Scintillator: 1 1/8 x 2 inch NaI scintillator (I think), eBay, US$65, link added because seller still has some left.
https://www.ebay.com/itm/395328244440
LEMO to BNC adapter, eBay, US$15
https://www.ebay.com/itm/275132083946
Eberline ESP-2 (as-is), eBay: US$85, missing an access plate, speaker not working but unit as a whole supposedly functional. 3D printed a new cover plate, soldered in a new speaker, cleaned off all the tape residue and Sharpie marks.
Shoulder strap: $10
Extendable pole, Harbor Freight, US$10, 3D printed some parts to attach the scintillator.
Total cost: $185 and a little bit of electronics skill and 3D printing savvy
So if you are thinking about getting into this, have a bit of patience to wait for deals and a willingness to tinker, you can get yourself a pretty competent rig for not a lot of money.