Growth and characterization study of K2PtCl6 type scintillators

Transparent, crack-free single crystal boules of 1-inch diameter Cs2HfCl6 (CHC) and Cs2HfCl4Br2 (CHCB) have been successfully grown using the vertical Bridgman method. Samples sized dia. 23mm×30mm and dia. 23mm×26mm, respectively, are characterized for their optical and scintillation properties. Energy resolutions of 3.5% and 3.7% (FWHM) at 662 keV as well as light yields of 23,000 ph/MeV and 20,000 ph/MeV have been calculated for CHC and CHCB, respectively. Results comparable to previously reported smaller crystals have been obtained. Studies on decay times, non-proportionality, and detector characterization are also reported. (This work was supported in part by U.S. Department of Energy under Grant #DE-SC0015733, U.S. National Science Foundation under Grant #HRD-1547757, and by U.S. National Aeronautics and Space Administration under Grant #NNX16AK42G).