Improvement of Energy Resolution and Neutron-Gamma Discrimination of NaI:Tl,6Li Single Crystal Scintillators by Ca2+ and Sr2+ Co-Doping

• Published in: IEEE transactions on nuclear science 2023-05, Vol.70 (5), p.840-846
• Main Authors: Wang, Jingkang, Wang, Chenger, Li, Huanyin, Shi, Jian, Wen, Xuemin, Shan, Chenyu, Ren, Guohao, Sun, Xilei, Wu, Yuntao
• Format: Article
• Language: English
• Subjects: 6Li; Bridgman method; Ca2+ and Sr2+ co-doping; Calcium ions; Crystal growth; Crystals; Doping; Energy resolution; energy resolution n/γ discrimination; Gamma rays; inorganic scintillator; Ions; NaI:Tl; Neutrons; Optical variables measurement; Photonics; Pulse shape; pulse shape discrimination (PSD); Scintillation counters; Scintillators; Single crystals; Strontium
• ISSN: 0018-9499; 1558-1578
• DOI: 10.1109/TNS.2023.3263522

NaI:Tl,6Li single crystals, due to low use cost and an efficient gamma ray ( \gamma ) and neutron ( n ) detection capability, have been regarded as promising n/\gamma scintillators. In this work, NaI:Tl,6Li single crystals co-doped with different Ca ^{2+} and Sr ^{2+} concentrations were grown by the multiampoule Bridgman method. Their \gamma -ray energy resolution and n/\gamma discrimination were improved. The \gamma -ray energy resolution at 662 keV was improved from 7.0% to 6.0% by Ca ^{2+} or Sr ^{2+} co-doping, despite at the expense of scintillation yield by around 20%. The pulse shape discrimination (PSD), expressed as figure-of-merits (FoMs) for neutron and \gamma -ray, was enhanced from 4.65 for NaI:Tl,6Li to 5.85 for Ca ^{2+} co-doping and 5.72 for Sr ^{2+} co-doping. This work not only highlights the effectiveness of the co-doping strategy on the improvement of NaI:Tl,6Li single crystal scintillator but also makes the crystal more competitive toward neutron and \gamma -ray detection applications.