Inorganic Halides for Scintillation
By: Luke Grocholl, Chemfiles Volume 5 Article 13
Luke Grocholl, Ph.D.
Materials Science Team
Sigma-Aldrich Corporation
The 1948 discovery by Hofstadter that sodium iodide doped with thallium exhibits extremely high light-yield and conversion efficiency launched the era of modern radiation spectrometry.1 More than half a century later, inorganic halide salts, particularly when doped, possess some of the best characteristics of all scintillation materials.2 In fact, thallium-doped sodium iodide still exhibits the highest conversion efficiency of any known scintillation material.
Rare-Earth Halides
Doped lanthanide halides are a promising new class of scintillation crystals. Recent papers3–5 show that these materials possess not only high light output, but also the proportionality necessary for high-energy resolution. In addition, doped lanthanide halides exhibit fast response times and good g-ray stopping efficiency. High-purity, anhydrous lanthanide halide source materials are expensive and difficult to obtain in the quantities necessary for bulk crystal growth. Sigma-Aldrich holds a unique position as a supplier of ultra-dry rareearth salts in bulk quantities.
Inorganic halide crystals represent the benchmark in scintillator materials. They continue to meet material challenges through active research and development. Essential to the growth of these crystals are ultra-high purity, anhydrous source materials. Proprietary Sigma- Aldrich technology is used to produce beaded materials whose reduced surface area minimizes moisture absorption and allows increased crucible loading, boosting crystal yield. Scrap shards cut from desired crystals can be reprocessed by Sigma-Aldrich to provide pristine materials, thus increasing the economic efficiency of scintillation crystal growth. Precursor materials must also be free of significant amounts of trace radioactive impurities. Sigma‑Aldrich has a center of excellence for high quality source materials, as well as technical knowledge and commitment, necessary to advance your high technology applications.
Halides
| Name | Formula | MW | CAS | MP | BP | Density at 25 °C | Cat. No. |
| Barium fluoride, anhydrous, powder, 99.999% | BaF2 | 175.34 | [7787-32-8] | 354 °C | 2260 °C | 4.89 g/mL | 449660-10G 449660-50G |
| Bismuth(III) fluoride, 99.99+% | BiF3 | 265.98 | [7787-61-3] | 649 °C | 900 °C | 8.3 g/mL | 401528-5G 401528-25G |
| Calcium fluoride, anhydrous, powder, 99.99% | CaF2 | 78.08 | [7789-75-5] | 1418 °C | 2260 °C | 3.18 g/mL | 449717-5G 449717-25G |
| Cerium(III) fluoride, anhydrous, powder, 99.99% | CeF3 | 197.12 | [7758-88-5] | 1430 °C | 2327 °C | 6.16 g/mL | 229555-2G 229555-10G 229555-50G |
| Cerium(III) chloride, anhydrous beads, –10 mesh, 99.99+% | CeCl3 | 246.48 | [7790-86-5] | 848 °C | 1730 °C | 4.00 g/mL | 429406-5G 429406-25G |
| Cerium(III) bromide, anhydrous, beads, particle size –10 mesh, 99.99% | CeBr3 | 379.85 | [14457-87-5] | 730–732 °C | 1705 °C | 5.18 g/mL | 563226-5G 563226-25G |
| Cesium fluoride, 99.99% | CsF | 151.90 | [13400-13-0] | 682 °C | 1231 °C | 4.115 g/mL | 255718-10G 255718-50G |
| Cesium iodide, anhydrous, beads, particle size –10 mesh, 99.999% | CsI | 259.81 | [7789-17-5] | 626 °C | 1280 °C | 4.51 g/mL | 429384-1G 429384-10G |
| Europium(III) fluoride, anhydrous, powder, 99.99% | EuF3 | 208.96 | [13765-25-8] | 1276 °C | 2500 °C | 449806-1G 449806-5G |
|
| Gadolinium(III) bromide, anhydrous, powder, 99.99% | GdBr3 | 396.98 | [13818-75-2] | 770 °C | 4.6 g/mL | 485020-2G 485020-10G |
|
| Lanthanum(III) fluoride, anhydrous, powder, 99.99% | LaF3 | 195.91 | [13709-38-1] | 1493 °C | 2327 °C | 5.936 g/mL | 449857-5G 449857-25G 449857-100G |
| Lanthanum(III) chloride, anhydrous, beads, particle size –10 mesh, 99.99+% | LaCl3 | 245.27 | [10099-58-8] | 860 °C | 1812 °C | 3.84 g/mL | 449830-5G 449830-25G |
| Lanthanum(III) bromide, anhydrous, beads, particle size –10 mesh, 99.99+% | LaBr3 | 378.64 | [13536-79-3] | 783 °C | 2280 °C | 5.06 g/mL | 449822-2G 449822-10G |
| Lanthanum(III) iodide, anhydrous, beads, particle size –10 mesh, 99.9% | LaI3 | 519.62 | [13813-22-4] | 772 °C | 5.63 g/mL | 413674-1G 413674-5G |
|
| Lead(II) iodide, beads, particle size –10 mesh, 99.999% | PbI2 | 461.01 | [10101-63-0] | 402 °C | 2672 °C | 6.16 g/mL | 554359-5G 554359-25G |
| Lutetium(III) chloride, anhydrous, powder, 99.99% | LuCl3 | 281.33 | [10099-66-8] | 279 °C | 905 °C | 3.98 g/mL | 450960-1G 450960-5G |
| Lutetium(III) bromide, anhydrous, powder, 99.99% | LuBr3 | 414.68 | [14456-53-2] | 1025 °C | 1440 °C | 587133-1G 587133-5G |
|
| Lutetium(III) iodide, anhydrous, powder, 99.9% | LuI3 | 555.68 | [13813-45-1] | 1050 °C | 1200 °C | 5.6 g/mL | 460575-1G 460575-5G |
| Mercury(II) bromide, anhydrous, beads, particle size –10 mesh, 99.999% | HgBr2 | 360.41 | [7789-47-1] | 236 °C | 318 °C | 6.05 g/mL | 449121-5G 449121-25G |
| Mercury(II) iodide, anhydrous, beads, particle size –10 mesh, 99.999% | HgI2 | 454.40 | [7774-29-0] | 259 °C | 322 °C | 6.21 g/mL | 449180-5G 449180-25G |
| Praseodymium(III) chloride, anhydrous, beads, particle size –10 mesh, 99.99% | PrCl3 | 247.27 | [10361-79-2] | 786 °C | 1710 °C | 4.00 g/mL | 451215-1G 451215-5G 451215-25G |
| Praseodymium(III) bromide, anhydrous, powder, 99.99% | PrBr3 | 380.63 | [13536-53-3] | 693 °C | 1547 °C | 5.30 g/mL | 439703-2G 439703-10G |
| Sodium iodide, anhydrous, beads, particle size –10 mesh, 99.999% | NaI | 149.89 | [7681-82-5] | 661 °C | 1304 ºC | 3.67 g/mL | 439681-5G 439681-25G |
| Thallium(I) bromide, anhydrous, beads, particle size –10 mesh, 99.999% | TlBr | 284.28 | [7789-40-4] | >300 °C | 815 °C | 7.5 g/mL | 336270-10G 336270-50G |
| Thallium(I) iodide, anhydrous, beads, particle size –10 mesh, 99.999% | TlI | 331.27 | [7790-30-9] | 440 °C | 824 °C | 7.29 g/mL | 458813-10G 458813-50G |
