• NUCLEAR TECHNIQUES
  • Vol. 47, Issue 7, 070202 (2024)
Qian YANG, Jie FAN*, and Shimeng XU
Author Affiliations
  • National Institute of Measurement and Testing Technology, Chengdu 610021, China
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    DOI: 10.11889/j.0253-3219.2024.hjs.47.070202 Cite this Article
    Qian YANG, Jie FAN, Shimeng XU. Absolute measurement of absorbed dose to water for γ-ray of 60Co by water calorimetry[J]. NUCLEAR TECHNIQUES, 2024, 47(7): 070202 Copy Citation Text show less
    Schematic diagram of the water calorimeter circuit
    Fig. 1. Schematic diagram of the water calorimeter circuit
    Side view of the sealed water calorimeter
    Fig. 2. Side view of the sealed water calorimeter
    Physical photo of absorbed dose to water absolute measurement device
    Fig. 3. Physical photo of absorbed dose to water absolute measurement device
    A sealed view of glass detection vessel with two thermistor probes aligned in the center
    Fig. 4. A sealed view of glass detection vessel with two thermistor probes aligned in the center
    不确定度来源Source of uncertainty相应值Value相对标准不确定度 Relative standard uncertainty
    si100uj100
    量热计重复性Reproducibility of calorimeter response0.18
    热敏电阻校准Thermistor calibration0.19
    热敏电阻位置Thermistor position0.06
    热损kHD Chemical heat defect1.000 00.30
    水比热容Cw Specific heat of water / (Jg∙K)-14.204 80.01
    热对流kv Heat flow by convection1.000 00.01
    热传导kc Heat flow by conduction0.996 30.15
    不同温度下水的密度不同kρ Water density1.000 60.01
    辐射场扰动kp Field perturbation1.002 10.05
    辐射场不均匀性kdd Lateral dose profile1.002 00.10
    探测器位置kprobe Probes and vessel positioning1.002 30.08
    辐照时间ktime R adiation time0.01
    二次求和 Quadratic summation0.280.35
    合成相对标准不确定度 Combined relative standard uncetainty in Dw,NIMTT0.45
    Table 1. NIMTT measurement uncertainty of absorbed dose to water for gamma ray of 60Co
    物理参数 CharacteristicsPTW 30013-9915PTW 30013-9916
    尺寸Dimensions壁厚度 Wall thickness / mm0.4250.425
    内径 Internal diameter / mm6.16.1
    腔体长度 Cavity length / mm2323
    尖点到有效测量点 Tip to reference point / mm1313
    电极Electrode长度 Length / mm21.221.2
    直径 Diameter / mm1.151.15
    体积Volume空气腔 Air cavity / mm3600600
    壁Wall材料 MaterialPMMA, GraphitePMMA, Graphite
    密度 Mensity / kg∙m-31 190, 1 8501 190, 1 850
    高压Voltage正电荷 Positive charge collected / V300300
    Table 2. Physical parameters of the transfer ionization chamber

    相对标准不确定度

    Relative standard uncertainty

    NIMTTNRC
    si100ui100si100ui100

    ND,w,lab相对标准不确定度

    Relative standard uncertainty of ND,w,lab

    0.550.45
    水吸收剂量Absorbed dose to water0.280.35
    电离室电离电流 Ionization current of each transfer chamber0.040.30
    水深度Depth in water0.05
    T, P修正Correction T, P0.050.10
    合并Quadratic summation0.290.47
    Table 3. Calibration factors ND,w,lab relative standard uncertainty of NIMTT and NRC

    实验室

    Laboratory

    电离室型号

    Ionization chamber type

    编号

    Number

    ND,w / mGy∙(nC)-1

    相对不确定度k=2

    Relative uncertainty k=2

    EnRD,wuc
    NRCPTW30013991553.670.9%
    PTW30013991653.700.9%
    NIMTTPTW30013991553.401.1%-0.360.995 00.007 1
    PTW30013991653.361.1%-0.450.993 70.007 1
    Table 4. Calibration factors and En values for NIMTT and NRC ionization chambers
    Qian YANG, Jie FAN, Shimeng XU. Absolute measurement of absorbed dose to water for γ-ray of 60Co by water calorimetry[J]. NUCLEAR TECHNIQUES, 2024, 47(7): 070202
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