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Scintillators play an important role in radiation detection and imaging. Thallium-doped cesium iodide (CsI:Tl) and sodium iodide (NaI:Tl) are two of the major scintillators that have been used for many applications for many decades. In this paper we will present an improved scintillation performance of Bridgman method grown CsI(Tl) and NaI(Tl) crystals developed by Xtallized Intelligence, Inc. (XI, Inc.) and we will compare the performance with commercially available CsI:Tl and NaI:Tl. In a preliminary testing using MicroFJ-60035-TSV silicon photomultipliers (ON Semiconductor), the newly developed and improved 12.5x12.5x6 mm3 CsI:Tl crystal has shown an energy resolution of 4.8% (FWHM) at 662 keV, compared to 7.2% obtained by a commercially available CsI:Tl with a size of 12.5x12.5x25 mm3. Energy resolution of 5.4% (FWHM) at 662 keV is obtained for the newly improved NaI:Tl crystal, compared to 7% obtained by a commercially available 1 in. dia. x 1 in. NaI(Tl). Comparison of the photo peak channel locations shows that the improved CsI:Tl and NaI:Tl developed by XI, Inc. have produced much larger signal amplitudes when compared to the commercially available CsI(Tl) and NaI:Tl. Improved decay time constants are presented as well.

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.

Research in ceramic scintillators has steadily progressed alongside the research in bulk single crystal scintillator growth. As interest in faster scintillation material production with lower cost increases, more research on scintillating ceramics is needed. Research targeting optimization of optically transparent ceramics that can rival bulk-grown crystals grown may lower cost, increase yield, increase volume, and improve energy resolution in applications and systems currently using sodium iodide and alike. Ceramic scintillators that are dense (>5 g/cm3), have high effective Z (>60), are bright (>40,000 photons/MeV), and are not sensitive to moisture as well as those that can be handled without protection are desired. Ultra-fast ceramic materials are also of interest. This paper presents an equipment design and technique to produce inorganic halide ceramic scintillators Cs2HfCl6 (CHC) and Tl2HfCl6 (THC). Improvements and optimization of CHC and THC ceramic scintillator fabrication are gauged by monitoring the energy resolution and peak position of 137Cs full energy peak at 662 keV. With a 1-inch diameter CHC ceramic scintillator, energy resolution of 5.4% (FWHM) and light yield of 20,700 ph/MeV are achieved, while with a 16-mm diameter THC ceramic scintillator, energy resolution of 5.1% (FWHM) and light yield of 27,800 ph/MeV are achieved. Decay times of 0.6 microseconds (21%) and 3.0 microseconds (79%) are measured for CHC and 0.3 microseconds (13%) and 1.0 microseconds (87%) for THC. Both ceramic CHC and THC scintillators have similarly good proportionality data when compared to their single crystal counterparts.

In this paper the growth of a 16mm diameter Ce-doped Tl$_2$NaYCl$_6$ and its characterization as a gamma-ray detector are reported. With a 16 mm dia. x 8 mm cylindrical sample, energy resolution of 4.1% (FWHM) at 662 keV and light yield of 27,800ph/MeV are measured. Decay times of 91 ns (34%), 462 ns (52%), and 2.1 microseconds (15%) are calculated. The x-ray excited emission spectrum exhibits bands that are similar to other Tl-based elpasolite scintillators like Tl$_2$NaYCl$_6$:Ce., Comment: arXiv admin note: text overlap with arXiv:1911.03611

Cesium cerium bromide (Cs2CeBr5) and potassium cerium bromide (K2CeBr5) are new scintillator materials for X-ray and gamma ray detector applications. Recently halide scintillator materials, such as Ce doped lanthanum bromide has been proved to be very important material for the same purpose. These materials are highly hygroscopic; a search for high light yield non-hygroscopic materials was highly desirable to advance the scintillator technology. In this paper, we are reporting the crystal growth of novel scintillator materials, cesium cerium bromide (Cs2CeBr5) and potassium cerium bromide (K2CeBr5). Crystals were successfully grown from the melt using the vertical Bridgman-Stockbarger technique, in a comparison with the high performance LaBr3 or LaCl3 crystals, cerium based alkali halides crystals, (Cs2CeBr5) and (K2CeBr5) have similar scintillation properties, while being much less hygroscopic. Furthermore, cesium based compounds will not suffer from the self-activity present in potassium and lanthanum compounds. However the Cs2CeBr5 crystals did not grow properly probably due to non-congruent melting or to some phase transition during cooling. Keywords." Scintillator materials; Ce3+; Energy resolution; Light yield; K2CeBr5