• NUCLEAR TECHNIQUES
  • Vol. 46, Issue 1, 010501 (2023)
Haoran LIU1,2, Qianqian ZHOU2, Juncheng LIANG2, and Daqing YUAN1,*
Author Affiliations
  • 1China Institute of Atomic Energy, Beijing 102413, China
  • 2National Institute of Metrology, Beijing 100029, China
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    DOI: 10.11889/j.0253-3219.2023.hjs.46.010501 Cite this Article
    Haoran LIU, Qianqian ZHOU, Juncheng LIANG, Daqing YUAN. Activity measurement of 55Fe using the liquid scintillation TDCR method[J]. NUCLEAR TECHNIQUES, 2023, 46(1): 010501 Copy Citation Text show less
    Diagram of liquid scintillation TDCR counter
    Fig. 1. Diagram of liquid scintillation TDCR counter
    Decay scheme of 55Fe
    Fig. 2. Decay scheme of 55Fe
    Venn diagrams of coincidence events(a) Triple coincidence events T, (b) Logical sums of the double coincidence events D
    Fig. 3. Venn diagrams of coincidence events(a) Triple coincidence events T, (b) Logical sums of the double coincidence events D
    Schematic of 55Fe sample preparation
    Fig. 4. Schematic of 55Fe sample preparation
    Efficiency curve of 55Fe in an Ultima Gold™ AB scintillation liquid
    Fig. 5. Efficiency curve of 55Fe in an Ultima Gold™ AB scintillation liquid
    参数类别Parameter category参数符号Parameter symbol参数值Parameter value
    K壳层俘获概率Capture probability of K shellPK0.880 44 (34)
    L1子壳层俘获概率Capture probability of L1 subshellPL10.101 88 (23)
    L2子壳层俘获概率Capture probability of L2 subshellPL25.012×10-4 (26)
    M1子壳层俘获概率Capture probability of M1 subshellPM10.015 99 (10)
    M2子壳层俘获概率Capture probability of M2 subshellPM27.43×10-5 (7)
    N1子壳层俘获概率Capture probability of N1 subshellPN10.001 120 (8)
    Table 1. EC probabilities for 55Fe

    样品编号

    Sample No.

    计数率RAB

    Count rate

    RAB / s-1

    计数率RBC

    Count rate

    RBC / s-1

    计数率RAC

    Count rate

    RAC / s-1

    计数率RD

    Count rate

    RD / s-1

    计数率RT

    Count rate

    RT / s-1

    修正因子kasym

    Correction factorkasym

    55Fe_11 999.21 922.51 995.53 350.61 283.31.001
    55Fe_21 042.91 087.91 001.61 765.9683.21.002
    55Fe_3990.81 011.41 119.11 761.5679.91.004
    55Fe_41 007.71 151.11 027.01 781.4702.21.005
    55Fe_51 023.91 058.31 079.01 769.3696.01.001
    Table 2. Net counting rates of 55Fe samples and asymmetry correction factors of PMT quantum efficiency

    样品编号

    Sample No.

    TDCR值

    TDCR value

    效率εDλ

    Efficiency εDλ

    质量

    Mass / g

    比活度Ao

    Specific activity

    Ao / kBq∙g-1

    比活度Ac

    Specific activity

    Ac / kBq∙g-1

    55Fe_10.383 00.622 70.057 1194.2194.16
    55Fe_20.386 90.627 20.029 8794.2694.10
    55Fe_30.386 00.626 10.029 8194.3793.96
    55Fe_40.394 20.635 30.029 5394.9594.45
    55Fe_50.393 40.634 40.029 6294.1594.09
    平均值Mean94.3994.15
    相对标准偏差Relative standard deviation0.34%0.19%
    Table 3. The measurement result of specific activity of the 55Fe solution

    不确定度分量

    Uncertainty component

    相对值Relative value / %

    注解

    Comments

    测量变异性Measurement variability0.18

    5个样品的相对标准偏差

    Relative standard deviation of five samples

    本底Background0.04

    本底扣除引起的不确定度

    Uncertainty due to background subtraction

    称重Weighing0.09

    天平校准引起的不确定度

    Uncertainty due to balance calibration

    死时间Dead time0.05

    灵敏度分析,改变死时间(10~500 μs),记录活度的变化,按均匀分布估计不确定度

    Sensitivity test, by adjusting the dead-time from 10 μs to 500 μs, recording the change of activity and estimating the uncertainty according to the uniform distribution

    符合分辨时间Resolving-time0.19灵敏度分析,改变分辨时间从50~200 ns, 记录活度的变化,按均匀分布估计不确定度Sensitivity test, by adjusting the resolving-time from 50 ns to 200 ns, recording the change of activity and estimating the uncertainty according to the uniform distribution
    衰变修正Decay correction<0.01

    55Fe半衰期((2.787±0.008)a)修正引起的不确定度

    Uncertainty due to55Fe half-life of (2.787±0.008) a

    计数时间Counting time<0.01

    由2 ns定时精度引起的不确定度

    Uncertainty due to timing accuracy of 2 ns

    电离猝灭参数kB

    Ionization quenching parameter kB

    0.14灵敏度分析,改变kB值(0.007~0.015 cm∙MeV-1),记录活度值的变化,按均匀分布估计不确定度Sensitivity test, by adjusting the kB value from 0.007 cm∙MeV-1 to 0.015 cm∙MeV-1, recording the change of activity and estimating the uncertainty according to the uniform distribution
    衰变数据及模型Decay data and model0.32灵敏度分析,改变EC概率和荧光产额,记录活度值的变化,按均匀分布估计Sensitivity tests, by adjusting EC probabilities and the fluorescence yield, recording the change of activity and estimating the uncertainty according to the uniform distribution

    合成相对标准不确定度

    The combined relative

    standard uncertainty ur

    0.45
    Table 4. The uncertainty components for specific activity of the 55Fe solution measured by liquid scintillation TDCR method
    Haoran LIU, Qianqian ZHOU, Juncheng LIANG, Daqing YUAN. Activity measurement of 55Fe using the liquid scintillation TDCR method[J]. NUCLEAR TECHNIQUES, 2023, 46(1): 010501
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