HPGe detector
A high-purity germanium semiconductor crystal cooled with liquid nitrogen to about 77 kelvin. Resolution at the 1,332 keV gamma line of cobalt-60 is around 1.8 keV, an order of magnitude better than a NaI(Tl) scintillator. The reference detector for neutron activation analysis and for any case where multiple gamma emitters have to be unscrambled in one spectrum.