Radiation hard gallium oxide scintillators for high count rate radiation detection

Abstract

Despite decades of materials research, the availability of appropriate crystalline radiation-hard scintillators with ultrafast decay times (∼10ns) and high light yields (>2000 ph/MeV) are still limited. In this study, we demonstrate the potential of gallium oxide (β-Ga2O3) based scintillators for high count rate applications. The low-cost rugged β-Ga2O3 scintillators were grown using the optical float zone (FZ) technique. Several dopants and growth atmospheres were used to demonstrate the balance between ultrafast primary decay time and the light yield of the scintillators. Light yields as high as 6446 ± 716 ph/MeV were obtained with 18.3 ns decay time for 662 keV gamma rays. Decay times as fast as 12ns were obtained with a 3212 ± 357 ph/MeV light yield. An excellent 662 keV gamma energy resolution of 7% was obtained using the β-Ga2O3:Ce crystals. Even with these excellent scintillation properties, the gamma radiation hardness of β-Ga2O3 crystals was better than the leading radiation-hard lead tungstate (PbWO4) crystals. Twenty-six scintillators fabricated from the grown β-Ga2O3 crystals were tested for radiation hardness with a 60Co gamma irradiation rate of 14 krad/h with a total radiation dose of 2 Mrad. The scintillation properties of these crystals remained unaffected. To date, no other scintillator has demonstrated such high radiation resistance. These FZ-grown low-cost, non-hygroscopic, and high-density β-Ga2O3 scintillators can replace the existing scintillators in many applications ranging from nuclear and high energy physics experiments to nuclear security.