Uranium Series Disequilibrium and Precision Measurement of Radionuclides Activity in Sediment Sample Using Low Background Gamma Spectrometry  

作　　者：Abdul J. Khan Umme-Farzana Syed Amy L. Roselan Cynthia A. Costello Abdul J. Khan;Umme-Farzana Syed;Amy L. Roselan;Cynthia A. Costello(Laboratory of Inorganic and Nuclear Chemistry, Division of Environmental Health Sciences, Wadsworth Center, New York State Department of Health, Empire State Plaza, Albany, NY, USA;Bureau of Environmental Radiation Protection, New York State Department of Health, Empire State Plaza, Albany, NY, USA)

机构地区：[1]Laboratory of Inorganic and Nuclear Chemistry, Division of Environmental Health Sciences, Wadsworth Center, New York State Department of Health, Empire State Plaza, Albany, NY, USA [2]Bureau of Environmental Radiation Protection, New York State Department of Health, Empire State Plaza, Albany, NY, USA

出　　处：《Journal of Geoscience and Environment Protection》2023年第10期119-140,共22页地球科学和环境保护期刊（英文）

摘　　要：Low background gamma spectrometry was used to measure the radionuclides activity of ²³⁸U, ²³²Th, and ²³⁵U series as well as ⁴⁰K and ¹³⁷Cs in a sediment sample. The goal of the study was to measure the ²³⁸U (63.3 keV peak of ²³⁴Th;1001 keV peak of ^234mPa) and ²³⁵U (143.76 keV, 163.33 keV, and 205.31 keV peaks) activity by low background gamma spectrometry in sediment sample. ²³⁵U activity in environmental samples is difficult to accurately measure by gamma spectrometry due to its low abundance in nature and low gamma line intensities at 143.76 keV, 163.33 keV, and 205.31 keV. We have shown that by using low background gamma spectrometry, it is possible to accurately measure the ²³⁵U activity in sediment samples. The ²³⁵U activity was measured without using the major peak of 185.7 keV (I_γ = 57.2%) which requires interference correction from 186.21 keV of ²²⁶Ra. ²²⁶Ra activity was determined by measuring ²²²Rn daughters (²¹⁴Pb and ²¹⁴Bi). The precision and accuracy of the gamma activity measurement in the sediment sample were verified by using the HPGe detectors with Certified Reference Material (CRM) Irish Sea Sediment (IAEA-385). The results obtained for the 63.33 keV energy line of ²³⁴Th are compared with the 1001 keV energy line of ^234mPa. The values of ²³⁸U and ²³⁵U activities, as well as ⁴⁰K, ¹³⁷Cs, and ²²⁶Ra, agreed with the certificate values of CRM. The results show that the ²³⁸U is in equilibrium with its daughters (²³⁴Th, ^234mPa, and ²¹⁰Pb). ²³²Th is also in equilibrium with its daughters (²²⁸Ra, ²¹²Pb, ²¹²Bi and ²⁰⁸Tl). ²³⁵U/²³⁸U activity ratio of 0.046 ± 0.007 in the sediment is constant in nature but fluctuates Low background gamma spectrometry was used to measure the radionuclides activity of ²³⁸U, ²³²Th, and ²³⁵U series as well as ⁴⁰K and ¹³⁷Cs in a sediment sample. The goal of the study was to measure the ²³⁸U (63.3 keV peak of ²³⁴Th;1001 keV peak of ^234mPa) and ²³⁵U (143.76 keV, 163.33 keV, and 205.31 keV peaks) activity by low background gamma spectrometry in sediment sample. ²³⁵U activity in environmental samples is difficult to accurately measure by gamma spectrometry due to its low abundance in nature and low gamma line intensities at 143.76 keV, 163.33 keV, and 205.31 keV. We have shown that by using low background gamma spectrometry, it is possible to accurately measure the ²³⁵U activity in sediment samples. The ²³⁵U activity was measured without using the major peak of 185.7 keV (I_γ = 57.2%) which requires interference correction from 186.21 keV of ²²⁶Ra. ²²⁶Ra activity was determined by measuring ²²²Rn daughters (²¹⁴Pb and ²¹⁴Bi). The precision and accuracy of the gamma activity measurement in the sediment sample were verified by using the HPGe detectors with Certified Reference Material (CRM) Irish Sea Sediment (IAEA-385). The results obtained for the 63.33 keV energy line of ²³⁴Th are compared with the 1001 keV energy line of ^234mPa. The values of ²³⁸U and ²³⁵U activities, as well as ⁴⁰K, ¹³⁷Cs, and ²²⁶Ra, agreed with the certificate values of CRM. The results show that the ²³⁸U is in equilibrium with its daughters (²³⁴Th, ^234mPa, and ²¹⁰Pb). ²³²Th is also in equilibrium with its daughters (²²⁸Ra, ²¹²Pb, ²¹²Bi and ²⁰⁸Tl). ²³⁵U/²³⁸U activity ratio of 0.046 ± 0.007 in the sediment is constant in nature but fluctuates

关 键 词：Low Background Gamma Spectrometry HPGe Detector SEDIMENT ²³⁸U ²³⁵U Secular Equilibrium 

分 类 号：O57[理学—粒子物理与原子核物理]