Not something you see everyday..

[sgt_bear]

I thought i had to share this one, you don't see such a monstrous detector everyday!
If only i had (alot of) spare money...

4x4" NaI(Ti) Detector on ebay:
https://www.ebay.com/itm/Bicron-Gamma-S ... 3990438352

[Sesselmann]

Yes, nice big crystal, but the resolution doesn't look great. If that's Co60 in the photo the separation between the peaks is very ordinary.

Steven

[iRad]

Steven is correct, resolution at 661 is only about 14%. These detectors were not built for spectroscopy use even when new, but were part of a portal monitoring system. Bigger is not always (not even usually) better for spectroscopy use, however if you want gross counts for survey use, it could be the trick... Cheers, Tom