کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1789542 | 1524380 | 2016 | 14 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Effects of increasing size and changing europium activator concentration in KCaI3 scintillator crystals
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
فیزیک و نجوم
فیزیک ماده چگال
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
KCaI3:Eu crystals have been identified as very promising for use in spectroscopic detector applications related to nuclear nonproliferation and domestic security efforts. Initial studies have shown for small crystals a few mm3 in size with 3% europium dopant concentration, a high light yield of >70,000Â ph/MeV and energy resolution of â3% at 662Â keV is attainable which is comparable with the highest performance scintillators discovered. In this work, single crystals of KCaI3 with a range of Eu2+ doping between 0 and 5Â at% substituting for Ca2+ were grown at 22Â mm diameter and their performance for gamma-ray spectroscopy studied. Comparisons among crystals approximately Ã22Â mmÃ22Â mm (8.4Â cm3 or â0.5Â in3) provide a more accurate understanding of how scintillation performance changes with Eu doping and increased crystal size. KCaI3 in the undoped form is shown to be a highly efficient intrinsic scintillator with a defect-related emission at 404Â nm which coexists with the Eu2+ 5d-4f emission in low dopant concentrations and is completely re-absorbed in more heavily doped crystals. For larger crystals, effects from self-absorption due to Eu activation become more evident by a near doubling of decay time for 0.5Â in3 crystals as the activator is increased from 0.5 to 5.0Â at% Eu. Comparisons of pulse-height spectra obtained for Ã22Â mmÃ22Â mm cylinders with varying Eu concentration suggests best performance is achieved using lower Eu additions closer to 0.5-1.0Â at%. Using a modified crystal packaging featuring an offset reflector geometry, 0.5Â in3 crystals of KCaI3:Eu can attain under 4% energy resolution at 662Â keV.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Crystal Growth - Volume 449, 1 September 2016, Pages 96-103
Journal: Journal of Crystal Growth - Volume 449, 1 September 2016, Pages 96-103
نویسندگان
Adam C. Lindsey, Mariya Zhuravleva, Yuntao Wu, Luis Stand, Matthew Loyd, Sasmit Gokhale, Merry Koschan, Charles L. Melcher,