CsI(Tl) Specially selected scintillation detector with SiPM readout. Crystal size 6*6*6 mm, Very nice resolution of 5.6%@662 keV measured using Atom Nano Pro electronics ans Cs137 point source installed in opposite to the SiPM side of crystal.
For best results use with 29.0 - 29.8 Volts bias at room temperature. Excellent gain - at least 1 nC of charge per MeV of dissipated energy with 29.5 V bias voltage. Actual item may slightly differ from photo.

General scintillator properties:
ParameterUnitValue
Max. Emission Wavelengthnm550
Average Light Decay Timens900
Average Light Yieldphotons/MeV60000
Densityg/cm34.51
Effective atomic numberZ54
Crystal sizemm / cm310*10*30 / 3
Energy rangekeV10-3000 min.

Want to build a portable and very sensitive and high resolution gamma spectrometer - it's your chance!
Check out my other lots, I hope you will find something interesting!
Any questions or requirements for detectors and/or electronics? Feel free to contact me.