A Novel Cost Effective Method for Growing High Performance Radiation Sensors

Certain lanthanide halides have significantly higher light output than NaI:Tl, the comparison standard for scintillators, plus other important properties, including fast decay times and excellent proportionality. Unfortunately, lanthanide halides grown by traditional melt processes have high production costs and limited availability. Crystals are usually limited to about 5 cm x 5 cm, right cylinder, and current growth techniques produce non-uniform dopant distributions (causing light output variation within the crystal, degrading energy resolution) and tend to produce asymmetric crystal structures (which tend to induce cracking). Even if these problems could be overcome for current fabrication methods, resulting material costs would be extraordinarily high. We therefore propose a rapid, alternate method to fabricate very thick, large area lanthanide halide slabs, in volume, at an order of magnitude reduced cost. This technique also allows formation of unconventional compositions that may further enhance scintillation properties—impossible using existing technologies. The Phase I research successfully demonstrated the feasibility of our novel growth technique, and our results exceeded expectations in many respects. The goal of Phase II is to extend the Phase I research to produce the large volume material, while achieving bright emission and excellent energy resolution, and commence efforts necessary for technology commercialization.