Abstract
A combinatorial approach where doped bulk scintillator materials can be rapidly optimized for their properties through concurrent extrinsic doping/co-doping strategies is presented. The concept that makes use of design of experiment, rapid growth, and evaluation techniques, and multivariable regression analysis, has been successfully applied to the engineering of NaI performance, a historical but mediocre performer in scintillation detection. Using this approach, we identified a three-element doping/co-doping strategy that significantly improves the material performance. The composition was uncovered by simultaneously screening for a beneficial co-dopant ion among the alkaline earth metal family and by optimizing its concentration and that of Tl+ and Eu2+ ions. The composition with the best performance was identified as 0.1% mol Tl+, 0.1% mol Eu2+, and 0.2% mol Ca2+. This formulation shows enhancement of energy resolution and light output at 662 keV, from 6.3 to 4.9%, and from 44 000 to 52 000 ph/MeV, respectively. The method, in addition to improving NaI performance, provides a versatile framework for rapidly unveiling complex and concealed correlations between material composition and performance, and should be broadly applicable to optimization of other material properties.
Highlights
The discovery and optimization of multi-element compounds out of a large combinatorial space is a daunting task
The maps allow for an estimation of which explanatory factors have an impact on the light output and energy resolution as well as a determination of which compositional set gives the optimal response within the combinatorial space explored
We present a combinatorial approach allowing to rapidly exploring the relationships between material composition and material properties
Summary
The discovery and optimization of multi-element compounds out of a large combinatorial space is a daunting task It has been especially challenging for doped bulk gamma detector materials, where one has to account for concentrations ranging over several orders of magnitude from elemental composition (lattice) to ppm levels (dopants). The arrangement of the experimental set, an orthogonal array, is designed to explore and optimize the material performance in a multi-dimensional space using the least possible number of experiments This framework was coupled to the LBNL high-throughput synthesis and characterization facility to rapidly produce and evaluate single crystalline samples based on a non-directional solidification technique.. LaBr3:Ce3þ with 200 ppm of Sr considerably improves the material energy resolution, from 2.7% to 2.0% at 662 keV.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
