  Scintillators cover an important wide range of applications in detection and
imaging. In this paper we are presenting growth and performance results of
several advanced large diameter thallium-based ternary halide crystals are
presented. Intrinsic crystals of TlMgCl3, TlCaCl3, TlCaBr3, and TlCa(Cl,Br)3,
as well as europium-doped TlCa2Br5 and TlCa(Cl,Br)3 are melt-grown by the
Bridgman method. These compounds have high Zeff due to thallium and expected to
have high physical densities. The best crystal quality and energy resolution
(FWHM) at 662 keV are observed for intrinsic TlMgCl3. The primary decay
constants for these compounds are in the range of 0.45 to 0.55 microseconds.
All of these compounds have proportional or linear response to gamma-ray above
100 keV.
