[summa_tech]

A few years ago, CZT detectors made by eV Products showed up in quantity on eBay. Pretty much everyone interested in radioactivity seemed to snap one up back then. It took a fairly long time for folks to figure out how to use them well! But they're really not bad, especially for the size.

Here's some spectra with 3% FWHM @ 662 keV:

https://maximus.energy/index.php/2020/05/01/gamma-spectrosco...

[ziofill]

You mean they’re good because the measurements are precise?

[summa_tech]

3% FWHM for something you could, at one time, buy for under $100 on eBay is very good. A typical scintillator + photomultiplier detector will get you about 6-7% (NaI:Tl scintillator). The Radiacode, which is super cute and all, gets about 7-9% depending on model.

Narrower FWHM means you will miss fewer energy peaks from isotopes.