  Nuclear and high energy physics research has a need for new, high performance
scintillators with high light yields; high densities, fast decay times, and are
radiation hard. In this paper we present crystal growth and results from 16-mm
diameter cerium (Ce)-doped Tl2LaCl5 (TLC) and europium (Eu)-doped TlCa2Br5(TCB)
as well as one-inch diameter cerium-doped Tl2GdBr5 (TGB) and
europium-dopedTlSr2I5 (TSI), each grown in a two-zone vertical furnace by the
modified Bridgman method. Samples extracted and processed from the grown boule
are characterized for their scintillation properties like energy resolution,
light yield, decay time and non-proportionality.Energy resolution (FWHM) at 662
keV of 5.1%, 3.4%, 4.0%, and 3.3% are obtained for samples of TGB, TLC, TCB,
and TSI, respectively. Ce-doped TGB and TLC have single decay time components
of 26 ns and 48 ns, respectively, while Eu-doped TCB and TSI have long decay
times with primary decay constants of 571 ns and 630 ns. These compounds
exhibit good proportionality behavior when compared toNaI:Tl and BGO.
