Study of ¹³⁸La radioactive decays using LaBr₃ scintillators

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• 作者：F.G.A. Quarati^a ; ^b ; ^{F.G.A.Quarati@tudelft.nl} ; I.V. Khodyuk^a ; C.W.E. van Eijk^a ; P. Quarati^c ; ^d ; P. Dorenbos^a
• 关键词：Beta decay ; Lanthanum-138 ; Unique forbidden decay ; Lanthanum halides ; Scintillation counters ; Intrinsic activity
• 刊名：Nuclear Instruments and Methods in Physics Research Section A ; Accelerators ; Spectrometers ; Detectors and Associated Equipment
• 出版年：2012
• 期刊代码：41_01689002
• 类别：ph
• 出版时间：11 August, 2012
• 卷：683
• 期：Complete
• 页码：46-52
• 文件大小：1016 K

摘要

We present a detailed investigation of the intrinsic activity of LaBr₃ scintillators from the natural abundance of radioactive isotope ¹³⁸La. Compared to earlier studies of lanthanum halides intrinsic activity, we gained a sharper insight by using samples of different sizes, ranging from 0.16 cm³ to 347 cm³, and by applying in our recent analysis results on the non-proportionality of scintillation response. In addition, we took advantage of the fact that LaBr₃ spectrometers offer a unique opportunity, never available before, to study the characteristics of the ¹³⁸La electron capture and 尾 radioactive decays that are 2nd order unique forbidden transitions. The observed shape of the 尾 continuum, measured down to the energy of 2 keV, is found to be different than expected from standard nuclear theory, indicating a possible underestimation of the screening effect for 尾 energies below 75 keV.